ORCID Profile
0000-0003-4165-6922
Current Organisation
Deakin University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Analytical Chemistry | Electroanalytical Chemistry | Analytical Spectrometry | Sensor Technology (Chemical aspects) | Separation Science | Analytical Chemistry not elsewhere classified | Quality Assurance, Chemometrics, Traceability and Metrological Chemistry | Physical Chemistry not elsewhere classified | Transition Metal Chemistry | Inorganic Chemistry | Nanochemistry and Supramolecular Chemistry | Flow Analysis | Electrochemistry | Analytical Biochemistry |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Scientific Instruments | Plant Production and Plant Primary Products not elsewhere classified | Human Pharmaceutical Treatments (e.g. Antibiotics) | Expanding Knowledge in Technology
Related Links
Publications
Chemiluminescence detection flow cells for flow injection analysis and high-performance liquid chromatography
Publisher: Springer Science and Business Media LLC
Date: 28-03-2012
DOI: 10.1007/S00216-012-5902-1
Abstract: We have examined a range of new and previously described flow cells for chemiluminescence detection. The reactions of acidic potassium permanganate with morphine and amoxicillin were used as model systems representing the many fast chemiluminescence reactions between oxidising agents and organic analytes, and the preliminary partial reduction of the reagent was exploited to further increase the rates of reaction. The comparison was then extended to high-performance liquid chromatography separations of α- and β-adrenergic agonists, with permanganate chemiluminescence detection. Flow cells constructed by machining novel channel designs into white polymer materials (sealed with transparent films or plates) have enabled improvements in mixing efficiency and overall transmission of light to the photodetector.
Emission from the working and counter electrodes under co-reactant electrochemiluminescence conditions
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1SC01236C
Abstract: Exploration of potential-dependent, multi-colour co-reactant electrochemiluminescence from multiple luminophores at the working and counter electrodes reveals new pathways to emission.
The determination of urea in soil extracts and related samples - A review
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/SR04028
Abstract: Although the dominant methods for the determination of urea in clinical applications incorporate selective enzymatic hydrolysis of urea, the determination of urea in soil extracts is complicated by the presence of urease inhibitors. The spectrophotometric determination of urea with an acidic solution diacetyl monoxime and semicarbazide is a viable option but traditional manual procedures are time-consuming. New variations on these procedures, based on microplates or flow-injection analysis methodologies, allow a far greater number of s les to be analysed with high precision and sensitivity.
Electrochemiluminescent Ruthenium(II) N-Heterocyclic Carbene Complexes: a Combined Experimental and Theoretical Study
Publisher: American Chemical Society (ACS)
Date: 18-06-2013
DOI: 10.1021/IC400263R
Abstract: A series of four Ru(II) complexes of the form [Ru(bpy)2(C(^)N)](2+) (where C(^)N is a bidentate pyridine-functionalized imidazolylidene- or benzimidazolylidene-based N-heterocyclic carbene (NHC) ligand and bpy is 2,2'-bipyridine) have been synthesized using a Ag(I) transmetalation protocol from the Ru(II) precursor compound, Ru(bpy)2Cl2. The synthesized azolium salts and Ru(II) complexes were characterized by elemental analysis, (1)H and (13)C NMR spectroscopy, cyclic voltammetry, and electronic absorption and emission spectroscopy. The molecular structures for two benzimidazolium salts and three Ru(II) complexes were determined by single crystal X-ray diffraction. The complexes display photoluminescence within the range 611-629 nm, with the emission wavelength of the benzimidazolylidene containing structures, slightly blue-shifted relative to the imidazolylidene containing complexes. All complexes exhibited a reversible, one-electron oxidation, which is assigned to the Ru(2+/3+) redox couple. When compared to [Ru(bpy)3](2+), complexes of imidazolylidene containing ligands were oxidized at more negative potentials, while those of the benzimidazolylidene containing ligands were oxidized at more positive potentials. All four complexes exhibited moderately intense electrochemiluminescence (ECL) with the obtained ECL spectra closely resembling the photoluminescence spectra. The ability to predictably fine-tune the highest occupied molecular orbital (HOMO) level of the Ru(II) complexes via the flexible synthetic strategy offered by NHCs is valuable for the design of ECL-based multiplexed detection strategies.
Correlation between acidic potassium permanganate chemiluminescence and in vitro cell culture assay: Physiologically meaningful antioxidant activity
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B9AY00242A
Hypohalites and related oxidants as chemiluminescence reagents: a review
Publisher: Wiley
Date: 03-2004
DOI: 10.1002/BIO.756
Abstract: This review concerns the use of hypochlorite, hypobromite and related oxidants (such as N-bromosuccinimide and 1,3-dibromo-5,5-dimethylhydantoin) as chemiluminescence reagents and includes references to 249 papers that were published prior to mid-2003. Particular emphasis has been placed on proposed emitting species and the mechanisms of the light-producing pathways. The analytical applications of this chemistry have been summarized in three tables: (1) quantification of hypohalites and related compounds (including halides, which are initially oxidized) (2) enhancement or inhibition of luminol chemiluminescence and (3) direct chemiluminescence reactions with hypohalite reagents.
Development of an automated DNA purification module using a micro-fabricated pillar chip
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B713332D
Abstract: We present a fully automated DNA purification module comprised of a micro-fabricated chip and sequential injection analysis system that is designed for use within autonomous instruments that continuously monitor the environment for the presence of biological threat agents. The chip has an elliptical flow channel containing a bed (3.5 x 3.5 mm) of silica-coated pillars with height, width and center-to-center spacing of 200, 15, and 30 microm, respectively, which provides a relatively large surface area (ca. 3 cm(2)) for DNA capture in the presence of chaotropic agents. We have characterized the effect of various fluidic parameters on extraction performance, including s le input volume, capture flow rate, and elution volume. The flow-through design made the pillar chip completely reusable carryover was eliminated by flushing lines with sodium hypochlorite and deionized water between assays. A mass balance was conducted to determine the fate of input DNA not recovered in the eluent. The device was capable of purifying and recovering Bacillus anthracis genomic DNA (input masses from 0.32 to 320 pg) from spiked environmental aerosol s les, for subsequent analysis using polymerase chain reaction-based assays.
Protocols for finding the most orthogonal dimensions for two-dimensional high performance liquid chromatography
Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.TALANTA.2014.11.037
Abstract: The selection of two high performance liquid chromatography (HPLC) columns with vastly different retention mechanisms is vital for performing effective two-dimensional (2D-) HPLC. This paper reports on a systematic method to select a pair of HPLC columns that provide the most different separations for a given s le. This was completed with the aid of a HPLC simulator that predicted retention profiles on the basis of real experimental data, which is difficult when the contents of s le matrices are largely-or completely-unknown. Peaks from the same compounds must first be matched between chromatograms to compare the retention profiles and optimised 2D-HPLC column selection. In this work, two methods of matching peaks between chromatograms were explored and an optimal pair of chromatography columns was selected for 2D-HPLC. First, a series of 17 antioxidants were selected as an analogue for a coffee extract. The predicted orthogonality of the standards was 39%, according to the fractional surface coverage 'bins' method, which was close to the actual space utilisation of the standard mixture, 44%. Moreover, the orthogonality for the 2D-HPLC of coffee matched the predicted value of 38%. The second method employed a complex s le matrix of urine to optimise the column selections. Seven peaks were confidently matched between chromatograms by comparing relative peak areas of two detection strategies: UV absorbance and potassium permanganate chemiluminescence. It was found that the optimal combinations had an orthogonality of 35% while the actual value was closer to 30%.
Annihilation electrogenerated chemiluminescence of mixed metal chelates in solution: modulating emission colour by manipulating the energetics
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4SC02697G
Abstract: The emissions of the mixed annihilation ECL of metal complexes can be effectively predicted by estimations of reaction exergonicity.
Chemiluminescence from reactions with bis-cyclometalated iridium complexes in acidic aqueous solution
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B905024H
Abstract: Chemical reactions between certain bis-cyclometalated iridium complexes, cerium(IV) and organic reducing agents in aqueous solution produce an emission of light which in some cases is more intense than that from analogous reactions with conventional ruthenium-based reagents, thus providing a new avenue for chemically-initiated luminescence detection.
Chemiluminescence from osmium(ii) complexes with phenanthroline, diphosphine and diarsine ligands
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2AN35446B
Abstract: The reaction of various [Os(L)(2)(L')](2+) complexes (where L and L' are phenanthroline, diphosphine or diarsine ligands) and organic reducing agents after chemical or electrochemical oxidation of the reactants produces an emission of light corresponding to MLCT transitions. In certain instances, the emission was greater than that of [Ru(bipy)(3)](2+), but the relative signals were dependent on many factors, including reagent concentration, mode of oxidation, reducing agent and the sensitivity of the photodetector over the wavelength range.
Chemiluminescence detection of heroin in illicit drug samples
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.TALANTA.2013.07.051
Abstract: Heroin (3,6-diacetylmorphine) and several important extraction and synthesis impurities (morphine, 6-monoacetylmorphine, codeine and 6-acetylcodeine) were determined in illicit drug s les, using high performance liquid chromatography with 'parallel segmented flow', which enabled the simultaneous use of three complementary modes of detection (UV-absorbance, tris(2,2'-bipyridine)ruthenium(III) chemiluminescence and permanganate chemiluminescence). This rapid and sensitive approach for the analysis of street heroin was used to explore the chemistry of a proposed heroin screening test that is based on the relative response with these two chemiluminescence reagents using flow injection analysis. Although heroin was the major constituent of the six drug s les (between 16% and 67% by mass), the synthetic by-product 6-acetylcodeine (2.5-8.3%) made a greater contribution to the total [Ru(bipy)3](3+) chemiluminescence response of the screening test. The signal with permanganate was primarily due to the presence of 6-monoacetylmorphine (0.9-29%), and was therefore indicative of the degree of s le degradation during clandestine manufacture or poor storage conditions prior to the drug seizure. In the second part of the screening test, the s le is treated with sodium hydroxide, which results in a large increase in the signal with permanganate, due to the rapid hydrolysis of heroin to 6-monoacetylmorphine. As the emission of these two reagents with morphinan-alkaloids and their derivatives largely depends on the substituent at the O(3) position, the slower hydrolysis of 6-monoacetylmorphine to morphine, and 6-acetylcodeine to codeine, did not have a major impact on the characteristic pattern of responses in the screening test.
Co-reactant Electrogenerated Chemiluminescence of Iridium(III) Complexes Containing an Acetylacetonate Ligand
Publisher: Wiley
Date: 03-05-2017
A rapid antioxidant assay based on acidic potassium permanganate chemiluminescence
Publisher: Elsevier BV
Date: 10-2010
Deficiency of selenoprotein S, an endoplasmic reticulum resident oxidoreductase, impairs the contractile function of fast-twitch hindlimb muscles
Publisher: American Physiological Society
Date: 08-2018
DOI: 10.1152/AJPREGU.00244.2017
Abstract: Selenoprotein S (Seps1) is an endoplasmic reticulum (ER) resident antioxidant implicated in ER stress and inflammation. In human vastus lateralis and mouse hindlimb muscles, Seps1 localization and expression were fiber-type specific. In male Seps1 +/− heterozygous mice, spontaneous physical activity was reduced compared with wild-type littermates ( d = 1.10, P = 0.029). A similar trend was also observed in Seps1 −/− knockout mice ( d = 1.12, P = 0.051). Whole body metabolism, body composition, extensor digitorum longus (EDL), and soleus mass and myofiber diameter were unaffected by genotype. However, in isolated fast EDL muscles from Seps1 −/− knockout mice, the force frequency curve (FFC 1–120 Hz) was shifted downward versus EDL muscles from wild-type littermates ( d = 0.55, P = 0.002), suggestive of reduced strength. During 4 min of intermittent, submaximal (60 Hz) stimulation, the genetic deletion or reduction of Seps1 decreased EDL force production ( d = 0.52, P 0.001). Furthermore, at the start of the intermittent stimulation protocol, when compared with the 60-Hz stimulation of the FFC, EDL muscles from Seps1 −/− knockout or Seps1 +/− heterozygous mice produced 10% less force than those from wild-type littermates ( d = 0.31, P 0.001 and d = 0.39, P = 0.015). This functional impairment was associated with reduced mRNA transcript abundance of thioredoxin-1 ( Trx1), thioredoxin interacting protein ( Txnip), and the ER stress markers Chop and Grp94, whereas, in slow soleus muscles, Seps1 deletion did not compromise contractile function and Trx1 ( d = 1.38, P = 0.012) and Txnip ( d = 1.27, P = 0.025) gene expression was increased. Seps1 is a novel regulator of contractile function and cellular stress responses in fast-twitch muscles.
Recent advances in mechanistic understanding and analytical methodologies of the electrochemiluminescence of tris(2,2′-bipyridine)ruthenium(II) and tri-n-propylamine
Publisher: Elsevier BV
Date: 10-2022
Determination of Citrus aurantium protoalkaloids using HPLC with acidic potassium permanganate chemiluminescence detection
Publisher: Elsevier BV
Date: 15-03-2010
DOI: 10.1016/J.TALANTA.2009.10.052
Abstract: Acidic potassium permanganate chemiluminescence was explored as a sensitive and selective mode of detection for phenolic phenethylamines (adrenergic amines) in consumer products containing Citrus aurantium extracts. Nine commercially available weight-loss products were analysed using rapid reversed-phase chromatography with a monolithic column (separation time of 4 min). The results were in good agreement with package labelling, with some notable exceptions. The products contained a wide concentration range of synephrine and total adrenergic amines, and the difference in consumer intake was even greater when the manufacturers' recommended daily consumption was considered. The quantity of the extract, often specified on the packaging as equivalent grams of dry C. aurantium fruit, was a poor indicator of the concentration of the active ingredients. Methionine, a thioether amino acid contained in some weight-loss products, was identified as a potential interferent for this mode of detection.
N-Acetylcysteine improves mitochondrial function and ameliorates behavioral deficits in the R6/1 mouse model of Huntington's disease
Publisher: Springer Science and Business Media LLC
Date: 06-01-2015
DOI: 10.1038/TP.2014.131
Monitoring urea levels during haemodialysis with a pulsed-flow chemiluminescence analyser
Publisher: Elsevier BV
Date: 06-2002
Determination of selected neurotransmitter metabolites using monolithic column chromatography coupled with chemiluminescence detection
Publisher: Elsevier BV
Date: 15-09-2005
DOI: 10.1016/J.TALANTA.2005.03.007
Abstract: The oxidation of selected clinically important neurotransmitter metabolites with acidic potassium permanganate in the presence of polyphosphates evokes chemiluminescence of sufficient intensity to enable the sensitive determination of these species. Limits of detection for 5-hydroxyindole-3-acetic acid (5-HIAA), vanilmandelic acid (VMA alpha,4-dihydroxy-3-methoxybenzeneacetic acid), 4-hydroxy-3-methoxyphenylglycol (MHPG), homovanillic acid (HVA, 4-hydroxy-3-methoxyphenylacetic acid) and 3,4-dihydroxyphenylacetic acid (DOPAC) were between 5x10(-9) and 4x10(-8)M, using flow-injection analysis methodology. In addition, we demonstrate the rapid determination of homovanillic acid and 5-hydroxyindole-3-acetic acid in human urine - without the need for extraction procedures - using monolithic column chromatography with chemiluminescence detection.
Boron Radicals Identified as the Source of the Unexpected Catalysis by Boron Nitride Nanosheets
Publisher: American Chemical Society (ACS)
Date: 23-01-2019
Abstract: Atomically thin boron nitride (BN) nanosheets were generally considered to be chemically inert until the recent discovery of the surprising catalysis. However, the origin of this unusual catalytic activity remains unclear. We have observed the free boron radicals at the edges and defective sites of BN nanosheets and demonstrated with both experimental and theoretical approaches that the boron radicals in the nanosheets can catalyze the chromogenic reaction of 3,5,3',5'-tetramethylbenzidine and serve as a source of reactive radicals for the co-reactant electrogenerated chemiluminescence of tris(2,2'-bipyridine)ruthenium(2+). These findings suggest BN nanosheets as a type of nonmetal catalyst.
Parallel segmented outlet flow high performance liquid chromatography with multiplexed detection
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.ACA.2013.04.014
Abstract: We describe a new approach to multiplex detection for HPLC, exploiting parallel segmented outlet flow - a new column technology that provides pressure-regulated control of eluate flow through multiple outlet channels, which minimises the additional dead volume associated with conventional post-column flow splitting. Using three detectors: one UV-absorbance and two chemiluminescence systems (tris(2,2'-bipyridine)ruthenium(III) and permanganate), we examine the relative responses for six opium poppy (Papaver somniferum) alkaloids under conventional and multiplexed conditions, where approximately 30% of the eluate was distributed to each detector and the remaining solution directed to a collection vessel. The parallel segmented outlet flow mode of operation offers advantages in terms of solvent consumption, waste generation, total analysis time and solute band volume when applying multiple detectors to HPLC, but the manner in which each detection system is influenced by changes in solute concentration and solution flow rates must be carefully considered.
Determination of arginine in dietary supplements
Publisher: Wiley
Date: 02-2005
DOI: 10.1002/JSFA.2084
Noble-metal-free Ni3N/g-C3N4 photocatalysts with enhanced hydrogen production under visible light irradiation
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8DT02456A
Abstract: Noble-metal-free Ni 3 N/g-C 3 N 4 heterojunctions that show high photocatalytic hydrogen evolution activity comparable to platinized g-C 3 N 4 were successfully synthesized.
Determination of neurotransmitters and their metabolites using one- and two-dimensional liquid chromatography with acidic potassium permanganate chemiluminescence detection
Publisher: Springer Science and Business Media LLC
Date: 07-12-2013
DOI: 10.1007/S00216-013-7514-9
Abstract: High-performance liquid chromatography with chemiluminescence detection based on the reaction with acidic potassium permanganate and formaldehyde was explored for the determination of neurotransmitters and their metabolites. The neurotransmitters norepinephrine and dopamine were quantified in the left and right hemispheres of rat hippoc us, nucleus accumbens and prefrontal cortex, and the metabolites vanillylmandelic acid, 3,4-dihydrophenylacetic acid, 5-hydroxyindole-3-acetic acid and homovanillic acid were identified in human urine. Under optimised chemiluminescence reagent conditions, the limits of detection for these analytes ranged from 2.5 × 10(-8) to 2.5 × 10(-7) M. For the determination of neurotransmitter metabolites in urine, a two-dimensional high-performance liquid chromatography (2D-HPLC) separation operated in heart-cutting mode was developed to overcome the peak capacity limitations of the one-dimensional separation. This approach provided the greater separation power of 2D-HPLC with analysis times comparable to conventional one-dimensional separations.
Chemiluminescence reactions with cationic, neutral, and anionic ruthenium(II) complexes containing 2,2′-bipyridine and bathophenanthroline disulfonate ligands
Publisher: Elsevier BV
Date: 15-07-2010
DOI: 10.1016/J.TALANTA.2010.05.047
Abstract: Ruthenium complexes containing 4,7-diphenyl-1,10-phenanthroline disulfonate (bathophenanthroline disulfonate BPS) ligands, Ru(BPS)(3)(4-), Ru(BPS)(2)(bipy)(2-) and Ru(BPS)(bipy)(2), were compared to tris(2,2'-bipyridine)ruthenium(II) (Ru(bipy)(3)(2+)), including examination of the wavelengths of maximum absorption and corrected emission intensity, photoluminescence quantum yield, stability of their oxidised ruthenium(III) form, and relative chemiluminescence intensities and signal-to-blank ratios with cerium(IV) sulfate and six analytes (codeine, morphine cocaine, potassium oxalate, furosemide and hydrochlorothiazide) in acidic aqueous solution. The presence of BPS ligands in the complex increased the photoluminescence quantum yield, but decreased the stability of the oxidised form of the reagent. In contrast to previous evidence showing much greater electrochemiluminescence intensities using Ru(BPS)(2)(bipy)(2-) and Ru(BPS)(bipy)(2), these complexes did not provide superior chemiluminescence signals than their homoleptic analogues.
Co‐Reactant and Annihilation Electrogenerated Chemiluminescence of [Ir(df‐ppy) 2 (ptb)] + Derivatives
Publisher: Wiley
Date: 03-03-2020
Pulsed flow chemistry: A new approach to solution handling for flow analysis coupled with chemiluminescence detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/B005118G
Selective Excitation of Concomitant Electrochemiluminophores: Tuning Emission Color by Electrode Potential
Publisher: Wiley
Date: 21-03-2012
Catalyst Luminescence Exploited as an Inherent In Situ Probe of Photoredox Catalysis
Publisher: Wiley
Date: 22-10-2020
The characteristic red chemiluminescence from reactions with acidic potassium permanganate: further spectroscopic evidence for a manganese(ii ) emitter
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B714147E
Abstract: A direct comparison of the laser-induced photoluminescence of manganese(ii) with the chemiluminescence from the reaction between acidic potassium permanganate and sodium borohydride was used to confirm that the characteristic red emission from this widely used chemiluminescence reagent emanates from an electronically excited manganese(ii) species.
High performance liquid chromatography with two simultaneous on-line antioxidant assays: Evaluation and comparison of espresso coffees
Publisher: Elsevier BV
Date: 15-05-2010
DOI: 10.1016/J.TALANTA.2010.01.024
Abstract: The antioxidant profiles of various espresso coffees were established using HPLC with UV-absorbance detection and two rapid, simultaneous, on-line chemical assays that enabled the relative reactivity of s le components to be screened. The assays were based on (i) the colour change associated with reduction of the 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH*) and (ii) the emission of light (chemiluminescence) upon reaction with acidic potassium permanganate. Results from the two approaches were similar and reflected the complex array of antioxidant species present in the s les. However, some differences in selectivity were observed. Chromatograms generated with the chemiluminescence assay contained more peaks, which was ascribed to the greater sensitivity of the reagent towards minor, readily oxidisable s le components. The three coffee s les produced closely related profiles, signifying their fundamentally similar chemical compositions and origin. Nevertheless, the overall intensity and complexity of the s les in both UV absorption and antioxidant assay chromatograms were aligned with the manufacturers description of flavour intensity and character.
Psychoactive Substances and How to Find Them: Electrochemiluminescence As a Strategy for Identification and Differentiation of Drug Species
Publisher: The Electrochemical Society
Date: 23-11-2020
DOI: 10.1149/MA2020-02582881MTGABS
Abstract: Rapid and continuous appearance of novel psychoactive substances (NPS) onto the global drug market has highlighted the significant requirement for new and alternative screening methodologies. Current screening protocols, primarily consisting of the colorimetric NIK® tests, are not only inadequate for NPS but they are not compatible with any matrix other than the pure drug product. Here we discuss the potential power of electrochemiluminescence (ECL) as a simple tool for drug screening. The intrinsic advantages of ECL make it an ideal candidate as an alternative analytical technique for the rapid identification of drug species, within a range of complex matrices. NPS, often contain a mixture of substances, while analysis of complex matrices can be challenging due to a number of potential interfering species present. Traditional ECL systems typically employ a single ruthenium based luminophore. This single complex approach often prevents the successful differentiation of structurally similar compounds, which typically interact with the complex via analogous mechanisms producing emission within the same potential regions. Multiplexed sensors utilising several different metal luminophores as well as pH controlled emission offer viable mechanisms to tackle the limited specificity associated with ECL techniques. Utilising tropane alkaloids, atropine and scopolamine as model compounds, a straightforward ECL sensor based upon a portable screen printed electrode set up, offering rapid results at minimal cost in a variety of complex matrices has been developed. The sensors portability matches that of current screening protocols but utilises less hazardous materials and removed subjectivity. Two alternative methodologies to improve the specificity offered by ECL were investigated within this study. By exploiting the relationship between pH and ECL emission the ability to differentiate between the two structurally similar species, upon a simple ruthenium based sensor, such as shown in Figure 1, is possible. The use of pH controlled ECL, allows for emission from one species to be “switched off” within a mixed s le. With knowledge of the target species pKa this methodology can be used to tailor the sensor toward a variety of species, offering improved specificity without having to alter sensor fabrication. The employment of different metal luminophores, such as iridium and osmium, can offer the possibility to increase specificity, with different selectivity offered by each luminophore. By using a combination of different metal luminophores the ability to differentiate between structurally similar species becomes possible, something currently not attainable when utilising a single luminophore system. Furthermore, the opportunity to negate previously encountered interference effects due to matrix composition becomes viable. By utilising a combination of different metal complexes we have successfully demonstrated the ability to effectively negate the interference effect from naturally occurring amino acids present in biological matrices such as human serum, a previously noted limitation for the use of ECL within biological matrices. Here we provide a strong proof-of-concept for the development of multiplexed ECL sensors, utilising several luminophores to tackle the limited specificity currently offered by ECL. By tackling this limitation, the potential applications of current ECL based sensors could be expanded significantly. Whats more our sensor design offers the ability to analyse a variety of complex biological matrices without the requirement of s le preparation. The potential to utilise one portable technique for drug screening across a variety of matrices, with the ability to tailor emission toward a specific drug species, without the requirement of a full lab facility will not only benefit the wider sensing community but such sensors offer the potential to reduce cost, increase throughput and simplify drug screening procedures in a variety of fields. Finally, a key challenge of electroanalytical sensors is multiplexed detection and this study will facilitate understanding of ECL based sensors to overcome this hurdle. Figure 1
Overcoming solvent mismatch limitations in 2D-HPLC with temperature programming of isocratic mobile phases
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5AY02528A
Abstract: Solvent incompatibility is a limiting factor when implementing 2D-HPLC. A programmed temperature gradient in the first dimension was developed to overcome this limitation by allowing an isocratic separation while maintaining selectivity.
Blind column selection protocol for two-dimensional high performance liquid chromatography
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.TALANTA.2016.03.056
Abstract: The selection of two orthogonal columns for two-dimensional high performance liquid chromatography (LC×LC) separation of natural product extracts can be a labour intensive and time consuming process and in many cases is an entirely trial-and-error approach. This paper introduces a blind optimisation method for column selection of a black box of constituent components. A data processing pipeline, created in the open source application OpenMS®, was developed to map the components within the mixture of equal mass across a library of HPLC columns LC×LC separation space utilisation was compared by measuring the fractional surface coverage, fcoverage. It was found that for a test mixture from an opium poppy (Papaver somniferum) extract, the combination of diphenyl and C18 stationary phases provided a predicted fcoverage of 0.48 and was matched with an actual usage of 0.43. OpenMS®, in conjunction with algorithms designed in house, have allowed for a significantly quicker selection of two orthogonal columns, which have been optimised for a LC×LC separation of crude extractions of plant material.
A hybrid FIA/HPLC system incorporating monolithic column chromatography
Publisher: Elsevier BV
Date: 09-2007
DOI: 10.1016/J.ACA.2007.03.048
Abstract: We have combined the generation of solvent gradients using milliGAT pumps, chromatographic separations with monolithic columns and chemiluminescence detection in an instrument manifold that approaches the automation and separation efficiency of HPLC, whilst maintaining the positive attributes of flow injection analysis (FIA), such as manifold versatility, speed of analysis and portability. As preliminary demonstrations of this hybrid FIA/HPLC system, we have determined six opiate alkaloids (morphine, pseudomorphine, codeine, oripavine, ethylmorphine and thebaine) and four biogenic amines (vanilmandelic acid, serotonin, 5-hydroxyindole-3-acetic acid and homovanillic acid) in human urine, using tris(2,2'-bipyridyl)ruthenium(III) and acidic potassium permanganate chemiluminescence detection.
Determination of intracellular glutathione and cysteine using HPLC with a monolithic column after derivatization with monobromobimane
Publisher: Wiley
Date: 2010
DOI: 10.1002/BMC.1327
Abstract: An optimized high-performance liquid chromatography (HPLC) method is used to show that, as myoblasts differentiate into multinucleated muscle fibers, there is a shift to a more oxidized cell redox state. The HPLC method incorporated derivatization with monobromobimane for the determination of the reduced (GSH) and oxidized (GSSG) forms of glutathione and the reduced (Cys) and oxidized (CysSS) forms of cysteine. The derivatization was optimized to improve the sensitivity of the approach the limits of detection for glutathione and cysteine were 3 x 10(-8) and 5 x 10(-8) M, respectively.
Near-ultraviolet chemiluminescence from the reaction of ammonia with hypobromite in aqueous solution
Publisher: Elsevier BV
Date: 11-2006
DOI: 10.1016/J.SAA.2005.12.033
Abstract: The chemiluminescence arising from the oxidation of ammonium chloride by sodium hypobromite in aqueous alkaline solution includes a series of peaks in the near-ultraviolet, which is not commonly observed in liquid-phase chemiluminescence. The dominant peak in that region has an intensity maximum at 292 nm and smaller peaks are observed at 313, 334 and 356 nm. The emitted photons are of similar energy to the Vergard-Kaplan transition of molecular nitrogen, a major product of this reaction. However, the spectral distribution is different to that of previously reported gas-phase chemiluminescence attributed to the Vergard-Kaplan transition.
'Cathodic' electrochemiluminescence of [Ru(bpy)3 ]2+ and tri-: N -propylamine confirmed as emission at the counter electrode
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CC03201K
Abstract: Monitoring emission and potentials at both the working and counter electrodes provides new insight into a proposed cathodic electrochemiluminescence system.
Determination of opiate alkaloids in process liquors using capillary electrophoresis
Publisher: Elsevier BV
Date: 02-2007
DOI: 10.1016/J.JPBA.2006.09.040
Abstract: This paper describes the determination of opiate alkaloids (morphine, codeine, oripavine and thebaine) in industrial process liquors using capillary zone electrophoresis with UV-absorption detection at 214 nm. A study of cyclodextrin type and concentration revealed that the addition of 30 mM hydroxypropyl-beta-cyclodextrin to the electrolyte solution (100mM Tris adjusted to pH 2.8) was suitable to resolve the four analytes of interest. Typical analysis time was 12 min and the limit of detection for each alkaloid was 2.5 x 10(-6) M. The results for the proposed methodology were in good agreement with those of a conventional HPLC procedure. Under the same conditions, short-end injection was used to reduce the effective separation length from 41.5 to 8.5 cm, which allowed the determination of morphine and thebaine in process liquors within 2.5 min.
Emitting Species in Chemiluminescence Reactions with Acidic Potassium Permanganate: A Re-Evaluation Based on New Spectroscopic Evidence
Publisher: Springer Science and Business Media LLC
Date: 08-04-2009
DOI: 10.1007/S10895-009-0485-8
Abstract: The reaction of acidic potassium permanganate with a wide range of compounds is known to produce a broad red emission, and there is strong evidence for an excited manganese(II) emitting species. Nevertheless, numerous researchers have proposed other emitters for reactions with acidic potassium permanganate, particularly for systems where fluorescent compounds were present, either as enhancers or reaction products. We have examined many reactions of this type and found that, in most cases, the same red emission was produced. There were, however, some exceptions, including the oxidation of dihydralazine, certain thiols and sulphite (each in the presence of an enhancer).
Electrochemiluminescent Monomers for Solid Support Syntheses of Ru(II)-PNA Bioconjugates: Multimodal Biosensing Tools with Enhanced Duplex Stability
Publisher: American Chemical Society (ACS)
Date: 16-02-2012
DOI: 10.1021/IC202761W
Abstract: The feasibility of devising a solid support mediated approach to multimodal Ru(II)-peptide nucleic acid (PNA) oligomers is explored. Three Ru(II)-PNA-like monomers, [Ru(bpy)(2)(Cpp-L-PNA-OH)](2+) (M1), [Ru(phen)(2)(Cpp-L-PNA-OH)](2+) (M2), and [Ru(dppz)(2)(Cpp-L-PNA-OH)](2+) (M3) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, dppz = dipyrido[3,2-a:2',3'-c]phenazine, Cpp-L-PNA-OH = [2-(N-9-fluorenylmethoxycarbonyl)aminoethyl]-N-[6-(2-(pyridin-2yl)pyrimidine-4-carboxamido)hexanoyl]-glycine), have been synthesized as building blocks for Ru(II)-PNA oligomers and characterized by IR and (1)H NMR spectroscopy, mass spectrometry, electrochemistry and elemental analysis. As a proof of principle, M1 was incorporated on the solid phase within the PNA sequences H-g-c-a-a-t-a-a-a-a-Lys-NH(2) (PNA1) and H-P-K-K-K-R-K-V-g-c-a-a-t-a-a-a-a-lys-NH(2) (PNA4) to give PNA2 (H-g-c-a-a-t-a-a-a-a-M1-lys-NH(2)) and PNA3 (H-P-K-K-K-R-K-V-g-c-a-a-t-a-a-a-a-M1-lys-NH(2)), respectively. The two Ru(II)-PNA oligomers, PNA2 and PNA3, displayed a metal to ligand charge transfer (MLCT) transition band centered around 445 nm and an emission maximum at about 680 nm following 450 nm excitation in aqueous solutions (10 mM PBS, pH 7.4). The absorption and emission response of the duplexes formed with the cDNA strand (DNA: 5'-T-T-T-T-T-T-T-A-T-T-G-C-T-T-T-3') showed no major variations, suggesting that the electronic properties of the Ru(II) complexes are largely unaffected by hybridization. The thermal stability of the PNA·DNA duplexes, as evaluated from UV melting experiments, is enhanced compared to the corresponding nonmetalated duplexes. The melting temperature (T(m)) was almost 8 °C higher for PNA2·DNA duplex, and 4 °C for PNA3·DNA duplex, with the stabilization attributed to the electrostatic interaction between the cationic residues (Ru(II) unit and positively charged lysine/arginine) and the polyanionic DNA backbone. In presence of tripropylamine (TPA) as co-reactant, PNA2, PNA3, PNA2·DNA and PNA3·DNA displayed strong electrochemiluminescence (ECL) signals even at submicromolar concentrations. Importantly, the combination of spectrochemical, thermal and ECL properties possessed by the Ru(II)-PNA sequences offer an elegant approach for the design of highly sensitive multimodal biosensing tools.
Chemiluminescence evidence supporting the selective role of ligands in the permanganate oxidation of micropollutants
Publisher: American Chemical Society (ACS)
Date: 20-09-2013
DOI: 10.1021/JP405985Y
Abstract: The selective increase in the oxidation rate of certain organic compounds with permanganate in the presence of environmental "ligands" and reduced species has been ascribed to the different reactivity of the target compounds toward Mn(III), which bears striking similarities to recent independent investigations into the use of permanganate as a chemiluminescence reagent. In spite of the importance of Mn(III) in the light-producing pathway, the dependence of the oxidation mechanism for any given compound on this intermediate could not be determined solely through the emission intensity. However, target compounds susceptible to single-electron oxidation by Mn(III) (such as bisphenol A and triclosan) can be easily distinguished by the dramatic increase in chemiluminescence intensity when a permanganate reagent containing high, stable concentrations of Mn(III) is used. The differences are accentuated under the low pH conditions that favor the chemiluminescence emission due to the greater reactivity of Mn(III) and the greater influence of complexing agents. This study supports the previously postulated selective role of ligands and reducing agents in permanganate oxidations and demonstrates a new approach to explore the chemistry of environmental manganese redox processes.
Switching off the interactions between graphene oxide and doxorubicin using vitamin C: combining simplicity and efficiency in drug delivery
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7TB03063K
Abstract: Delivery of doxorubicin using graphene oxide is remarkably improved by adding a little amount of vitamin C.
Electrochemiluminescence
Publisher: Springer International Publishing
Date: 2022
The Tandem Photoredox Catalysis Mechanism of [Ir(ppy)2(dtb-bpy)]+ Enabling Access to Energy Demanding Organic Substrates
Publisher: American Chemical Society (ACS)
Date: 23-09-2019
DOI: 10.1021/JACS.9B07370
Abstract: We report the discovery of a tandem catalytic process to reduce energy demanding substrates, using the [Ir(ppy)
A conceptual framework for the development of iridium(iii ) complex-based electrogenerated chemiluminescence labels
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SC01391A
Abstract: A new strategy to create iridium( iii )-based ECL labels reveals limitations of conventional approaches.
Stable tris(2,2′-bipyridine)ruthenium(III) for chemiluminescence detection
Publisher: American Chemical Society (ACS)
Date: 08-06-2011
DOI: 10.1021/AC200913W
Abstract: Two exceedingly stable [Ru(bipy)(3)](3+) reagents were prepared by dissolving either [Ru(bipy)(3)](ClO(4))(2) in acetonitrile (containing 0.05 M HClO(4)) or [Ru(bipy)(3)]Cl(2)·6H(2)O in 95:5 glacial acetic acid-acetic anhydride (containing 0.05 M H(2)SO(4)) followed by oxidation with PbO(2). These conveniently prepared solutions provide highly reproducible chemiluminescence detection over long periods of analysis, avoiding the need for recalibration or preparation of fresh reagent solutions and without the complications associated with online chemical or electrochemical oxidations. The reagent prepared in acetonitrile produced much greater signal intensities with a range of analytes and was deemed most suitable for high-performance liquid chromatography (HPLC) with postcolumn chemiluminescence detection.
Green chemiluminescence from a bis-cyclometalated iridium(III) complex with an ancillary bathophenanthroline disulfonate ligand
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1AN15315C
Abstract: The reaction of a fluorinated iridium complex with cerium(IV) and organic reducing agents generates an intense emission with a significant hypsochromic shift compared to contemporary chemically-initiated luminescence from metal complexes.
Enhanced permanganate chemiluminescence
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0AN00588F
Abstract: The significant enhancement of acidic potassium permanganate chemiluminescence by Mn(II) results from the concomitant presence of permanganate and Mn(III) in the reagent solution, which enables rapid production of the excited Mn(II) emitter with a wide range of analytes. Furthermore, the key Mn(III) co-reactant can be quickly generated by reducing permanganate with sodium thiosulfate, instead of the slow (~24 h) equilibration required when Mn(ii) is used. The emission from reactions with analytes such as tyrosine and fenoterol was over two orders of magnitude more intense than with the traditional permanganate reagent.
Improvement of cognitive function in schizophrenia with N-acetylcysteine: A theoretical review
Publisher: Informa UK Limited
Date: 30-05-2020
Advances in the use of acidic potassium permanganate as a chemiluminescence reagent: A review
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.ACA.2013.11.016
Abstract: We review the analytical applications of acidic potassium permanganate chemiluminescence published since our previous comprehensive review in mid-2007 to early 2013. This includes a critical evaluation of evidence for the emitting species, the influence of additives such as polyphosphates, formaldehyde, sulfite, thiosulfate, lanthanide complexes and nanoparticles, the development of a generalized reaction mechanism, and the use of this chemistry in pharmaceutical, clinical, forensic, food science, agricultural and environmental applications.
A redox-mediator pathway for enhanced multi-colour electrochemiluminescence in aqueous solution
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1SC05609C
Abstract: A water-soluble Ir( iii ) complex is shown to enhance the ‘remote’ mechanism of the most widely used co-reactant ECL reaction of tris(2,2′-bipyridine)ruthenium( ii ) with tripropylamine.
Mobile phone-based electrochemiluminescence sensing exploiting the ‘USB On-The-Go’ protocol
Publisher: Elsevier BV
Date: 09-2015
Determination of urea using high-performance liquid chromatography with fluorescence detection after automated derivatisation with xanthydrol
Publisher: Elsevier BV
Date: 08-2007
DOI: 10.1016/J.CHROMA.2007.05.085
Abstract: A high-performance liquid chromatography (HPLC) method for the determination of urea that incorporates automated derivatisation with xanthydrol (9H-xanthen-9-ol) is described. Unlike the classic xanthydrol approach for the determination of urea, which involves the precipitation of dixanthylurea (N,N'-di-9H-xanthen-9-ylurea), the derivatisation procedure employed in this method produces N-9H-xanthen-9-ylurea, which remains in solution and can be quantified using fluorescence detection (lambda(ex)=213 nm lambda(em)=308 nm) after chromatographic separation from interferences. The limit of detection for urea was 5 x 10(-8) M (0.003 mg L(-1)). This method was applied to the determination of urea in human and animal urine and in wine.
A review of recent advances in chemiluminescence detection using nano-colloidal manganese(IV)
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.ACA.2014.06.008
Abstract: The application of 'soluble' (colloidal) manganese(IV) for chemiluminescence detection is reviewed, focussing on papers published since the last comprehensive review of the subject in 2008. Advances in this reagent system include: the on-line formation of manganese(IV) new insight into the light-producing pathway and selectivity of the reagent its application to assess total antioxidants in plant derived s les and oxidative stress in biological fluids and tissues and the replacement of the formaldehyde enhancer with ethanol.
Blue Electrogenerated Chemiluminescence from Water-Soluble Iridium Complexes Containing Sulfonated Phenylpyridine or Tetraethylene Glycol Derivatized Triazolylpyridine Ligands
Publisher: Wiley
Date: 03-09-2015
Abstract: Incorporating phenylpyridine- and triazolylpyridine-based ligands decorated with methylsulfonate or tetraethylene glycol (TEG) groups, a series of iridium(III) complexes has been created for green and blue electrogenerated chemiluminescence under analytically useful aqueous conditions, with tri-n-propylamine as a coreactant. The relative electrochemiluminescence (ECL) intensities of the complexes were dependent on the sensitivity of the photodetector over the wavelength range and the pulse time of the applied electrochemical potential. In terms of the integrated area of corrected ECL spectra, with a pulse time of 0.5 s, the intensities of the Ir(III) complexes were between 18 and 102 % that of [Ru(bpy)3 ](2+) (bpy=2,2'-bipyridine). However, when the intensities were measured with a typical bialkali photomultiplier tube, the signal of the most effective blue emitter, [Ir(df-ppy)2 (pt-TEG)](+) (df-ppy=2-(2,4-difluorophenyl)pyridine anion, pt-TEG=1-(2-(2-(2-(2-hydroxyethoxy)ethoxy)ethoxy)ethyl)-4-(2-pyridyl)-1,2,3-triazole), was over 1200 % that of the orange-red emitter [Ru(bpy)3 ](2+) . A combined experimental and theoretical investigation of the electrochemical and spectroscopic properties of the Ir(III) complexes indicated that the greater intensity from [Ir(df-ppy)2 (pt-TEG)](+) relative to those of the other Ir(III) complexes resulted from a combination of many factors, rather than being significantly favored in one area.
N-Acetylcysteine (NAC) in Schizophrenia Resistant to Clozapine: A Double-Blind, Randomized, Placebo-Controlled Trial Targeting Negative Symptoms
Publisher: Oxford University Press (OUP)
Date: 20-07-2022
Abstract: Clozapine is the most effective antipsychotic for treatment-resistant schizophrenia, yet a significant proportion of in iduals on clozapine continue to experience disabling symptoms, despite being treated with an adequate dose. There is a need for adjunct treatments to augment clozapine, notably for negative and cognitive symptoms. One such potential agent is the glutathione precursor N-acetylcysteine (NAC). A randomized double-blind, multi-center, placebo-controlled trial for clozapine patients with enduring psychotic symptoms (n = 84) was undertaken to investigate the efficacy of adjunctive NAC (2 g daily) for negative symptoms, cognition and quality of life (QoL). Efficacy was assessed at 8, 24, and 52 weeks. NAC did not significantly improve negative symptoms (P = .62), overall cognition (P = .71) or quality of life (Manchester quality of life: P = .11 Assessment of quality of life: P = .57) at any time point over a 1-year period of treatment. There were no differences in reported side effects between the groups (P = .26). NAC did not significantly improve schizophrenia symptoms, cognition, or quality of life in treatment-resistant patients taking clozapine. This trial was registered with “Australian and New Zealand Clinical Trials” on the 30 May, 2016 (Registration Number: ACTRN12615001273572).
A Rapid Test for Heroin (3,6‐Diacetylmorphine) Based on Two Chemiluminescence Reactions
Publisher: Wiley
Date: 31-08-2006
DOI: 10.1111/J.1556-4029.2006.00215.X
Abstract: A rapid method for screening drug seizure s les for 3,6-diacetylmorphine (heroin), which consists of a simple hydrolysis procedure and flow-injection analysis with two chemiluminescence reagents, is described. Before hydrolysis, 3,6-diacetylmorphine evokes an intense response with a tris(2,2'-bipyridyl)ruthenium(III) reagent (prepared by dissolving the perchlorate salt in acetonitrile), and a relatively weak chemiluminescence response with a second reagent: potassium permanganate in an aqueous acidic polyphosphate solution. However, the permanganate reagent is extremely sensitive toward the hydrolysis products of 3,6-diacetylmorphine (i.e., 6-monoacetylmorphine and morphine). Some compounds commonly found in drug laboratories may cause false positives with tris(2,2'-bipyridyl)ruthenium(III), but do not produce the markedly increased response with the permanganate reagent after the hydrolysis procedure. The combination of these two tests therefore provides an effective presumptive test for the presence of 3,6-diacetylmorphine, which we have verified with 14 s les obtained from a forensic science laboratory.
Autocatalytic nature of permanganate oxidations exploited for highly sensitive chemiluminescence detection
Publisher: American Chemical Society (ACS)
Date: 17-02-2010
DOI: 10.1021/AC9028399
Abstract: Manganese(II) salts catalyze the chemiluminescent oxidation of organic compounds with acidic potassium permanganate. The formation of insoluble manganese(IV) species from the reaction between manganese(II) and permanganate can be prevented with sodium polyphosphate, and therefore, relatively high concentrations of the catalyst can be added to the reagent before the light-producing reaction is initiated. The rapid and intense emissions from these manganese(II) catalyzed chemiluminescence reactions provide highly sensitive detection and greater compatibility with liquid chromatography.
Chemiluminescence from the reaction of tin(ii) with tris(2,2′- bipyridyl)ruthenium(iii)
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B918641G
Abstract: Unlike many other metal and metalloid ions, tin(II) elicits intense, analytically useful chemiluminescence upon reaction with tris(2,2'-bipyridyl)ruthenium(III) in acidic aqueous solution. This finding provides new insight into the nature of this widely used reagent and has enabled the first direct, selective determination of a metal ion with tris(2,2'-bipyridyl)ruthenium(III).
Analytical methodology for the determination of urea: current practice and future trends
Publisher: Elsevier BV
Date: 05-2002
Potential‐Resolved Electrogenerated Chemiluminescence for the Selective Detection of Multiple Luminophores
Publisher: Wiley
Date: 02-02-2015
Abstract: Electrogenerated chemiluminescence (ECL) is fundamentally dependent on the applied electrode potential, and measuring ECL intensity over a range of different potentials is commonly used to examine the underlying chemical reaction pathways responsible for the emission of light. Several research groups have now demonstrated that the applied potential can be exploited to selectively elicit ECL from: 1) multiple excited states within a single chemical species 2) multiple emitters sharing a common co-reactant or 3) distinct ECL systems. This new generation of multiplexed ECL processes has been facilitated by the extensive development of novel electrochemiluminophores and instrumental approaches such as the near-continuous collection of ECL spectra with CCD detectors during voltammetry or chrono erometry experiments.
Determination of intracellular glutathione and glutathione disulfide using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1AN00004G
Abstract: Measurement of glutathione (GSH) and glutathione disulfide (GSSG) is a crucial tool to assess cellular redox state. Herein we report a direct approach to determine intracellular GSH based on a rapid chromatographic separation coupled with acidic potassium permanganate chemiluminescence detection, which was extended to GSSG by incorporating thiol blocking and disulfide bond reduction. Importantly, this simple procedure avoids derivatisation of GSH (thus minimising auto-oxidation) and overcomes problems encountered when deriving the concentration of GSSG from 'total GSH'. The linear range and limit of detection for both analytes were 7.5 × 10(-7) to 1 × 10(-5) M, and 5 × 10(-7) M, respectively. GSH and GSSG were determined in cultured muscle cells treated for 24 h with glucose oxidase (0, 15, 30, 100, 250 and 500 mU mL(-1)), which exposed them to a continuous source of reactive oxygen species (ROS). Both analyte concentrations were greater in myotubes treated with 100 or 250 mU mL(-1) glucose oxidase (compared to untreated controls), but were significantly lower in myotubes treated with 500 mU mL(-1) (p < 0.05), which was rationalised by considering measurements of H(2)O(2) and cell viability. However, the GSH/GSSG ratio in myotubes treated with 100, 250 and 500 mU mL(-1) glucose oxidase exhibited a dose-dependent decrease that reflected the increase in intracellular ROS.
Solution mixing and the emission of light in flow-cells for chemiluminescence detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0AN00591F
Abstract: Constructing flow-through reactors for chemiluminescence detection by machining channels into polymer disks has enabled the exploration of new configurations and materials that can improve signal intensity beyond that attainable with the traditional coiled-tubing design. Several approaches to merge reactant solutions were examined: an intersection, chamber or deeper well in the centre of a serpentine configuration flow-cell (directly in front of a photomultiplier tube), or a confluence point outside the detection zone. For several analytically useful, rapid chemiluminescence reactions, the single-inlet flow-cell with external Y-piece was most suitable, but for others (such as KMnO(4)/Mn(II) with morphine, and [Ir(f-ppy)(2)BPS](-) with fluoroquinolones) the dual-inlet configuration provided greater signals. The introduction of central mixing zones with larger widths than the channel reduced the chemiluminescence response. The reversing turns of a serpentine channel promote efficient mixing and greater chemiluminescence intensities than a spiral channel, but increasing the sharpness of the turns created areas of poor solution flow and decreased the chemiluminescence response. Teflon disks impregnated with glass microspheres increased the chemiluminescence signals by 13%-17%, due to the greater reflection of stray light towards the photodetector.
Bimodal Electrochemiluminescence Microscopy of Single Cells
Publisher: American Chemical Society (ACS)
Date: 25-04-2023
Tris(2,2′-bipyridyl)ruthenium(ii ) chemiluminescence enhanced by silver nanoparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B612244B
Abstract: Mixtures of silver(I) and citrate that are used to produce silver nanoparticles evoke intense chemiluminescence with tris(2,2'-bipyridyl)ruthenium(II) and cerium(IV), which can be exploited for the determination of citrate ions and other analytes over a wide concentration range.
Autocatalytic Chemiluminescence Sheds New Light on the Classic Permanganate-Oxalate Reaction
Publisher: American Chemical Society (ACS)
Date: 03-05-2013
DOI: 10.1021/JP312603M
Abstract: The emission of light from the permanganate-oxalate reaction enables monitoring of intermediates not accessible through traditional spectrophotometric interrogation. Despite the inherent complexity of the underlying chemical reactions and equilibria, the emission intensity-time profile was characterized by a simple model combining previously independent minimalistic descriptions of chemiluminescence and autocatalysis. The generation of the electronically excited [Mn(II)]* emitter and the acceleration of the reaction even in the presence of high initial concentrations of Mn(II) (under conditions that preclude accumulation of colloidal Mn(IV)) provide new evidence for the reduction of manganese species by a reactive radical intermediate as a supplementary positive feedback loop to the formation of Mn(II).
Soluble manganese(IV) as a chemiluminescence reagent for the determination of opiate alkaloids, indoles and analytes of forensic interest
Publisher: Elsevier BV
Date: 30-03-2007
DOI: 10.1016/J.TALANTA.2006.08.037
Abstract: We present the results of our investigations into the use of soluble manganese(IV) as a chemiluminescence reagent, which include a significantly faster method of preparation and a study on the effect of formaldehyde and orthophosphoric acid concentration on signal intensity. Chemiluminescence detection was applied to the determination of 16 analytes, including opiate alkaloids, indoles and analytes of forensic interest, using flow injection analysis methodology. The soluble manganese(IV) reagent was less selective than either acidic potassium permanganate or tris(2,2'-bipyridyl)ruthenium(III) and therefore provided a more universal chemiluminescence detection system for HPLC. A broad spectral distribution with a maximum at 730+/-5nm was observed for the reaction between the soluble manganese(IV) and a range of analytes, as well as the background emission from the reaction with the formaldehyde enhancer. This spectral distribution matches that reported for chemiluminescence reactions with acidic potassium permanganate, where a manganese(II) emitting species was elucidated. This provides further evidence that the emission evoked in reactions with soluble manganese(IV) also emanates from a manganese(II) species, and not bimolecular singlet oxygen as suggested by previous authors.
Evaluation of coloured materials in microfluidic flow-cells for chemiluminescence detection
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.ACA.2017.03.001
Abstract: Recent advances in the construction of chemiluminescence flow-cells has included high precision milling of channels into a range of different polymer materials, in efforts to maximise the transfer of light from the chemical reaction to the photodetector. However, little is known of the extent that the colour of polymer materials will influence this transfer. This may become increasingly important as chemiluminescence detection zones are integrated with other operations within microfluidic devices or micro total analysis systems (μTAS). Herein, we compare microfluidic flow-cells fabricated from five polymer sheets (clear, white, black, red, blue), using two flow-cell designs (spiral and serpentine), two modes of photodetection, and four chemiluminescence reactions that provide a range of different emission colours. The direct transfer of light from the reaction within the white flow-cell channel to the photodetector made only minor contributions (10%-20%) to the measured intensity, with the majority of the measured light first interacting with the polymer material into which the channels were machined. The extent that the emitted light was absorbed or reflected by the coloured polymer materials was dependent on not only the properties of the polymer, but also the spectral distribution of the chemiluminescence. The changes in chemiluminescence intensities from absorption of light by the flow-cell materials can be accompanied by distortion of the spectral distribution.
Control of Excitation and Quenching in Multi‐colour Electrogenerated Chemiluminescence Systems through Choice of Co‐reactant
Publisher: Wiley
Date: 09-09-2014
Abstract: We demonstrate a new approach to manipulate the selective emission in mixed electrogenerated chemiluminescence (ECL) systems, where subtle changes in co-reactant properties are exploited to control the relative electron-transfer processes of excitation and quenching. Two closely related tertiary-amine co-reactants, tri-n-propylamine and N,N-diisopropylethylamine, generate remarkably different emission profiles: one provides distinct green and red ECL from [Ir(ppy)3] (ppy=2-phenylpyridinato-C2,N) and a [Ru(bpy)3](2+) (bpy=2,2'-bipyridine) derivative at different applied potentials, whereas the other generates both emissions simultaneously across a wide potential range. These phenomena can be rationalized through the relative exergonicities of electron-transfer quenching of the excited states, in conjunction with the change in concentration of the quenchers over the applied potential range.
Near-infrared chemiluminescence from the oxidation of ammonia in aqueous alkaline solution
Publisher: Wiley
Date: 05-01-2005
DOI: 10.1002/JNR.20399
Abstract: Neurofilament (NF) polymers are conveyed from cell body to axon tip by slow axonal transport, and disruption of this process is implicated in several neuronal pathologies. This movement occurs in both anterograde and retrograde directions and is characterized by relatively rapid but brief movements of neurofilaments, interrupted by prolonged pauses. The present studies combine pharmacologic treatments that target actin filaments or microtubules with imaging of NF polymer transport in living axons to examine the dependence of neurofilament transport on these cytoskeletal systems. The heavy NF subunit tagged with green fluorescent protein was expressed in cultured sympathetic neurons to visualize NF transport. Depletion of axonal actin filaments by treatment with 5 microM latrunculin for 6 hr had no detectable effect on directionality or transport rate of NFs, but frequency of movement events was reduced from 1/3.1 min of imaging time to 1/4.9 min. Depolymerization of axonal microtubules using either 5 microM vinblastine for 3 hr or 5 microg/ml nocodazole for 4-6 hr profoundly suppressed neurofilament transport. In 92% of treated neurons, NF transport was undetected. These observations indicate that actin filaments are not required for neurofilament transport, although they may have subtle effects on neurofilament movements. In contrast, axonal transport of NFs requires microtubules, suggesting that anterograde and retrograde NF transport is powered by microtubule-based motors.
Any Old Radical Won’t Do: An EPR Study of the Selective Excitation and Quenching Mechanisms of [Ru(bipy)3]2+ Chemiluminescence and Electrochemiluminescence
Publisher: Wiley
Date: 07-06-2011
Evaluation of tris(4,7-diphenyl-1,10-phenanthrolinedisulfonate)ruthenium(II) as a chemiluminescence reagent
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.ACA.2008.12.030
Abstract: Previous studies have suggested that tris(4,7-diphenyl-1,10-phenanthrolinedisulfonate)ruthenium(II) (Ru(BPS)(3)(4-)) has great potential as a chemiluminescence reagent in acidic aqueous solution. We have evaluated four different s les of this reagent (two commercially available and two synthesised in our laboratory) in comparison with tris(2,2'-bipyridine)ruthenium(II) (Ru(bipy)(3)(2+)) and tris(1,10-phenanthroline)ruthenium(II) (Ru(phen)(3)(2+)), using a range of structurally erse analytes. In general, Ru(BPS)(3)(4-) produced more intense chemiluminescence, but the oxidised Ru(BPS)(3)(3-) species is less stable in aqueous solution than Ru(bipy)(3)(3+) and produced a greater blank signal than Ru(bipy)(3)(3+) or Ru(phen)(3)(3+), which had a detrimental effect on sensitivity. Although the complex is often depicted with the sulfonate groups of the BPS ligand in the para position on the phenyl rings, NMR characterisation revealed that the commercially available BPS material used in this study was predominantly the meta isomer.
The importance of chain length for the polyphosphate enhancement of acidic potassium permanganate chemiluminescence
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.ACA.2014.07.012
Abstract: Sodium polyphosphate is commonly used to enhance chemiluminescence reactions with acidic potassium permanganate through a dual enhancement mechanism, but commercially available polyphosphates vary greatly in composition. We have examined the influence of polyphosphate composition and concentration on both the dual enhancement mechanism of chemiluminescence intensity and the stability of the reagent under analytically useful conditions. The average chain length (n) provides a convenient characterisation, but materials with similar values can exhibit markedly different distributions of phosphate oligomers. There is a minimum polyphosphate chain length (∼6) required for a large enhancement of the emission intensity, but no further advantage was obtained using polyphosphate materials with much longer average chain lengths. Providing there is a sufficient average chain length, the optimum concentration of polyphosphate is dependent on the analyte and in some cases, may be lower than the quantities previously used in routine detection. However, the concentration of polyphosphate should not be lowered in permanganate reagents that have been partially reduced to form high concentrations of the key manganese(III) co-reactant, as this intermediate needs to be stabilised to prevent formation of insoluble manganese(IV).
Electrochemically, Spectrally, and Spatially Resolved Annihilation‐Electrogenerated Chemiluminescence of Mixed‐Metal Complexes at Working and Counter Electrodes
Publisher: Wiley
Date: 08-05-2018
Chemiluminescence Detector with a Serpentine Flow Cell
Publisher: American Chemical Society (ACS)
Date: 17-11-2008
DOI: 10.1021/AC801842Q
Abstract: We present a new chemiluminescence detector, with solution channels that have been machined into a Teflon disk and sealed with a sapphire window. The configuration of the flow cell can be conveniently modified by replacing the Teflon disk. A comparison of some existing and novel designs, using the chemiluminescence reaction of morphine with acidic potassium permanganate and the bioluminescence reaction of ATP with the commercially available "BacTiter-Glo" reagent, has revealed that a serpentine channel allows greater quantities of light to be captured than a spiral channel, due to more efficient mixing of the analyte and reagent solutions within the cell.
Manganese(III) and manganese(IV) as chemiluminescence reagents: A review
Publisher: Elsevier BV
Date: 08-2008
DOI: 10.1016/J.ACA.2008.06.041
Abstract: Although potassium permanganate [Mn(VII)] has been used extensively as a chemiluminescence reagent for many decades, other manganese-based oxidants have only recently been explored for this purpose. There is strong evidence to suggest that, like permanganate, manganese(III) and manganese(IV) oxidants react with many molecules to produce an excited manganese(II) species that emits light. However, these reagents differ markedly in terms of selectivity, and possess characteristics that provide new avenues for detection, such as the immobilisation of solid manganese dioxide, the production of 'soluble' manganese(IV) nanoparticles, and the electrochemical generation of manganese(III). In this review we examine the emergence of these alternative manganese oxidants as chemiluminescence reagents.
Red–Green–Blue Electrogenerated Chemiluminescence Utilizing a Digital Camera as Detector
Publisher: American Chemical Society (ACS)
Date: 20-02-2014
DOI: 10.1021/AC404135F
Abstract: Exploiting the distinct excitation and emission properties of concomitant electrochemiluminophores in conjunction with the inherent color selectivity of a conventional digital camera, we create a new strategy for multiplexed electrogenerated chemiluminescence detection, suitable for the development of low-cost, portable clinical diagnostic devices. Red, green and blue emitters can be efficiently resolved over the three-dimensional space of ECL intensity versus applied potential and emission wavelength. As the relative contribution ratio of each emitter to the photographic RGB channels is constant, the RGB ECL intensity versus applied-potential curves could be effectively isolated to a single emitter at each potential.
Ethanol as an alternative to formaldehyde for the enhancement of manganese(IV) chemiluminescence detection
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.TALANTA.2014.07.002
Abstract: Previous applications of manganese(IV) as a chemiluminescence reagent have required the use of formaldehyde to enhance the emission intensity to analytically useful levels. However, this known human carcinogen (by inhalation) is not ideal for routine application. A wide range of alternative enhancers have been examined but to date none have been found to provide the dramatic increase in chemiluminescence intensities obtained using formaldehyde. Herein, we demonstrate that ethanol offers a simple, safe and inexpensive alternative to the use of formaldehyde for manganese(IV) chemiluminescence detection, without compromising signal intensity or sensitivity. For ex le, chemiluminescence signals for opiate alkaloids using 50-100% ethanol were 0.8-1.6-fold those using 2M formaldehyde. This innocuous alternative enhancer is shown to be a particularly effective for the direct detection of thiols and disulfides by manganese(IV) chemiluminescence, which we have applied to a simple HPLC procedure to determine a series of biomarkers of oxidative stress.
Cathodic electrogenerated chemiluminescence of tris(2,2′-bipyridine)ruthenium(ii) and peroxydisulfate at pure Ti3C2Tx MXene electrodes
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0CC02993A
Abstract: Two-dimensional transition metal carbide (Ti 3 C 2 T x MXene) film as a novel electrode material for electrogenerated chemiluminescence of tris(2,2′-bipyridine)ruthenium( ii ) and peroxydisulfate.
Chemiluminescence detection of cannabinoids and related compounds with acidic potassium permanganate
Publisher: Wiley
Date: 29-03-2012
DOI: 10.1002/DTA.1328
Abstract: This is the first report of chemiluminescence from the reaction of cannabinoids with acidic potassium permanganate, which we have applied to the high performance liquid chromatography (HPLC) determination of cannabidiol (CBD) in industrial-grade hemp. The intensities of the light-producing reactions with two commercially available cannabinoid standards were compared to that of seven model phenolic analytes. Resorcinol, representing the parent phenolic moiety of the cannabinoid class, was shown to react with the permanganate reagents in a manner more similar to phenol than to its hydroxyphenol positional isomers, pyrocatechol and hydroquinone. Alkyl substituents on the phenolic ring, however, have a considerable impact on emission intensity that is dependent upon the position of the groups and the composition of the permanganate reagent. This analytical approach has potential for the determination of other cannabinoids including Δ(9) -tetrahydrocannabinol in drug-grade cannabis.
Kinetics and selectivity of permanganate chemiluminescence: A study of hydroxyl and amino disubstituted benzene positional isomers
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.ACA.2011.09.024
Abstract: Examination of the chemiluminescence reactions of dihydroxybenzenes, aminophenols and phenylenediamines with acidic potassium permanganate has provided a new understanding of the relationships between analyte structure, reaction conditions, kinetics of the light-producing pathway and emission intensity, with broad implications for this widely utilised chemiluminescence detection system. Using a permanganate reagent prepared in a polyphosphate solution and adjusted to pH 2.5, large differences in the rate of reaction with different positional isomers were observed, with the meta-substituted forms reacting far slower and therefore exhibiting much lower chemiluminescence intensities in flow analysis systems. The preliminary partial reduction of permanganate to form significant concentrations of Mn(III) increased the rate of reaction with all analytes tested, resulting in comparable or (in the case of aminophenol and phenylenediamine) even greater emission intensities for the meta-isomers, demonstrating the opportunity to tune the selectivity of the reagent towards certain classes of compound or even specific positional isomers of the same compound. Using more acidic permanganate reagents, in which polyphosphates are not required, the discrepancy between the chemiluminescence intensities was still observed, but was less prominent due to the generally faster rates of reaction. The enhancement of these chemiluminescence reactions by on-line addition of formic acid or formaldehyde can in part also be attributed to the generation of significant pools of the key Mn(III) precursor to the emitting species.
Probing the tunable surface chemistry of graphene oxide
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CC02518D
Abstract: Detailed understanding of surface chemistry of graphene oxide (GO) has been explored by probing the interactions transitions on GO/[Ru(bpy) 3 ] 2+ surface.
Flow analysis based on a pulsed flow of solution: theory, instrumentation and applications
Publisher: Elsevier BV
Date: 06-12-2002
DOI: 10.1016/S0039-9140(02)00426-5
Abstract: The increased demands placed on solution propulsion by programmed flow systems, such as sequential injection analysis, lab-on-value technology, bead injection and multi-commutation, has highlighted the inability of many conventional pumps to generate a smooth, consistent flow. A number of researchers have examined ways to overcome the inadvertent, uncontrolled pulsation caused by the mechanical aciton of peristaltic pumps. In contrast, we have developed instruments that exploit the characteristics of a reproducible pulsed flow of solution. In this paper, we discuss our instrumental approaches and some applications that have benefited from the use of a reproducible pulsed flow rather than the traditional linear flow approach. To place our approach in the context of the continuously developing field of flow analysis, an overview of other programmed flow systems is also presented.
Tris(2,2′-bipyridyl)ruthenium(II) chemiluminescence
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B518454A
Abstract: This paper critically reviews analytical applications of the chemiluminescence from tris(2,2'-bipyridyl)ruthenium(II) and related compounds published in the open literature between mid-1998 and October 2005. Following the introduction, which summarises the reaction chemistry and reagent generation, the review ides into three major sections that focus on: (i) the techniques that utilise this type of detection chemistry, (ii) the range of analytes that can be determined, and (iii) analogues and derivatives of tris(2,2'-bipyridyl)ruthenium(II).
Determination of synephrine in weight-loss products using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection
Publisher: Elsevier BV
Date: 06-2007
DOI: 10.1016/J.ACA.2007.04.038
Abstract: Adrenergic amines found in extracts of Citrus aurantium (bitter orange) evoke analytically useful chemiluminescence with acidic potassium permanganate in the presence of polyphosphates. From corrected chemiluminescence spectra, the wavelength of maximum intensity for these reactions was 680+/-5 nm and, using flow injection analysis methodology, limits of detection for synephrine, octopamine, tyramine and hordenine were found to be between 1x10(-9) and 1x10(-8) M. We have applied this method of detection to the rapid determination of synephrine in dietary supplements using monolithic column chromatography.
Designing Carbon Fiber Composite Interfaces: Reactive Sizing Derived from Terpenes
Publisher: American Chemical Society (ACS)
Date: 07-02-2023
Direct Detection of Biologically Significant Thiols and Disulfides with Manganese(IV) Chemiluminescence
Publisher: American Chemical Society (ACS)
Date: 06-07-2011
DOI: 10.1021/AC2010668
Abstract: The quantification of low-molecular mass thiols and disulfides involved in cellular redox processes is hindered by oxidation or degradation of analytes during conventional s le preparation steps (including deproteinization and derivatization). Researchers therefore seek techniques that minimize s le handling and permit direct detection of thiols and disulfides within a single chromatographic separation. We demonstrate a new HPLC procedure for these biologically important analytes that incorporates direct chemiluminescence detection with a manganese(IV) reagent. A mixture of seven thiols and disulfides (cysteine, N-acetylcysteine, homocysteine, glutathione (GSH), glutathione disulfide (GSSG), cystine, and homocystine) in their native forms were separated using a C18 column within 20 min. Detection limits for these analytes ranged from 5 × 10(-8) to 1 × 10(-7) M, and the precision for retention times and peak areas was excellent, with relative standard deviations of less than 0.3% and 2%, respectively. This approach was employed to determine two key biomarkers of oxidative stress, GSH and GSSG, in whole blood taken from 12 healthy volunteers. S les were deproteinized, centrifuged, and diluted prior to analysis using a simple procedure that was shown to avoid significant artificial oxidation of GSH.
Comparison of homoleptic and heteroleptic 2,2′-bipyridine and 1,10-phenanthroline ruthenium complexes as chemiluminescence and electrochemiluminescence reagents in aqueous solution
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.ACA.2008.12.042
Abstract: We have conducted a comprehensive comparative study of Ru(bipy)(3)(2+), Ru(bipy)(2)(phen)(2+), Ru(bipy)(phen)(2)(2+), and Ru(phen)(3)(2+) as chemiluminescence and electrochemiluminescence (ECL) reagents, to address several previous conflicting observations and gain a greater insight into their potential for chemical analysis. Clear trends were observed in many of their spectroscopic and electrochemical properties, but the relative chemiluminescence or ECL intensity with a range of analytes/co-reactants is complicated by the contribution of numerous (sometimes opposing) factors. Significantly, the reversibility of cyclic voltammetric responses for the complexes decreased as the number of phenanthroline ligands was increased, due to the lower stability of their ruthenium(III) form in the aqueous solvent. This trend was also evident over a longer timescale when the ruthenium(III) form was spectrophotometrically monitored after chemical oxidation of the ruthenium(II) complexes. In general, the greater stability of Ru(bipy)(3)(3+) resulted in lower blank signals, although this effect was less pronounced with ECL, where the reagent is oxidised in the presence of the co-reactants. Nevertheless, this shows the need to compare signal-to-blank ratios or detection limits, rather than the more common comparisons of overall signal intensity for different ruthenium complexes. Furthermore, our results support previous observations that, compared to Ru(bipy)(3)(2+), Ru(phen)(3)(2+) provides greater ECL and chemiluminescence intensities with oxalate, which in some circumstances translates to superior detection limits, but they do not support the subsequent generalised notion that Ru(phen)(3)(2+) is a more sensitive reagent than Ru(bipy)(3)(2+) for all analytes.
A potential-controlled switch on/off mechanism for selective excitation in mixed electrochemiluminescent systems
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2SC21707D
Extending Photocatalyst Activity through Choice of Electron Donor
Publisher: American Chemical Society (ACS)
Date: 11-01-2022
Accumulation and excretion of morphine by Calliphora stygia, an Australian blow fly species of forensic importance
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.JINSPHYS.2010.09.005
Abstract: This study examined the ability of the forensically important blow fly, Calliphora stygia to actively excrete morphine, thereby maintaining a low morphine level within its body when fed on a diet containing morphine at low (7pmolg(-1)) and high (17.5pmolg(-1)) concentrations. Morphine was accumulated within the bodies of maggots (≈70% within the tissues) at concentrations which were lower than that of the meat (3-24%). The morphine content of the initial developing stages (second and third instar maggots) maintained on the high morphine diet was higher than those on the low morphine diet. Morphine was cleared from the body with negatively exponential kinetics (High morphine group: Morphine (pmolg(-1) wet weight)=8425e(-0.014t). Low morphine group: Morphine (pmolg(-1) wet weight)=2180e(-0.010t)). Clearance constants for morphine by animals in both groups were similar and thus both groups had a similar ability to excrete morphine. The Malpighian tubules of maggots were able to actively secrete morphine using a transport mechanism that transports small type II organic cations, such as morphine and quinine. The rate of morphine secretion by the Malpighian tubules could explain the clearance of the drug by the maggots. As the morphine was transported across the Malpighian tubules cells, a significant proportion was metabolised into a compound that is yet to be fully characterised.
Colour tuning and enhancement of gel-based electrochemiluminescence devices utilising Ru(ii ) and Ir(iii ) complexes
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CC05031K
Abstract: Combining luminophores in ratios that compensate for energy transfer provides a range of new emission colours for gel-based electrochemiluminescence devices.
Carbon reinforced carbon fibers: Using surface modification as a route to enhanced physical performance
Publisher: Elsevier BV
Date: 02-2022
Plasmonic nanopapers: flexible, stable and sensitive multiplex PUF tags for unclonable anti-counterfeiting applications
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR01223H
Abstract: Highly flexible and stable plasmonic nanopaper comprised of silver nanocubes and cellulose nanofibres was fabricated through a self-assembly-assisted vacuum filtration method.
Chemiluminescence and electrochemiluminescence detection of controlled drugs
Publisher: Wiley
Date: 10-12-2010
DOI: 10.1002/DTA.236
Abstract: We review the determination of various controlled drugs (opioids, tranquilizers, stimulants, and hallucinogens) using flow-analysis methodologies (flow injection analysis, high performance liquid chromatography, capillary electrophoresis, and microfluidic devices) with chemiluminescence and electrochemiluminescence reagents such as luminol, diaryloxalates, tris(2,2'-bipyridine)ruthenium(II), permanganate, manganese(IV), and sulfite, for industrial, clinical, pharmaceutical, and forensic science applications.
The assessment of π–π selective stationary phases for two-dimensional HPLC analysis of foods: Application to the analysis of coffee
Publisher: Elsevier BV
Date: 15-09-2010
DOI: 10.1016/J.TALANTA.2010.06.065
Abstract: Differences between alkyl, dipole-dipole, hydrogen bonding, and pi-pi selective surfaces represented by non-resonance and resonance pi-stationary phases have been assessed for the separation of 'Ristretto' café espresso by employing 2DHPLC techniques with C18 phase selectivity detection. Geometric approach to factor analysis (GAFA) was used to measure the detected peaks (N), spreading angle (beta), correlation, practical peak capacity (n(p)) and percentage usage of the separations space, as an assessment of selectivity differences between regional quadrants of the two-dimensional separation plane. Although all tested systems were correlated to some degree to the C18 dimension, regional measurement of separation ergence revealed that performance of specific systems was better for certain s le components. The results illustrate that because of the complexity of the 'real' s le obtaining a truly orthogonal two-dimensional system for complex s les of natural origin may be practically impossible.
The analysis of café espresso using two-dimensional reversed phase–reversed phase high performance liquid chromatography with UV-absorbance and chemiluminescence detection
Publisher: Elsevier BV
Date: 15-09-2010
DOI: 10.1016/J.TALANTA.2010.06.066
Abstract: In this study, an activity based screening technique combining two-dimensional liquid chromatography (2DHPLC) with UV-absorbance and chemiluminescence detection was applied to study "Ristretto", "Decaffeinatto" and "Volluto" espresso coffees. This technique, which coupled the separation power of 2DHPLC with the sensitivity and selectivity of the chemiluminescence detection, offers great potential for screening complex s les for antioxidant compounds. Detailed information regarding the complexity of the s le, and the variation between these three coffees could be obtained using this multidimensional-hyphenated method of analysis.
Chemiluminescence detection of amino acids and related compounds using acidic potassium permanganate, manganese(IV) or tris(2,2′-bipyridine) ruthenium(III)
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.TALANTA.2012.06.022
Abstract: We have explored the chemiluminescence response of amino acids and related compounds (including the tripeptide glutathione, and disulfides: cystine, homocystine and glutathione disulfide) with several new adaptations of the permanganate and tris(2,2'-bipyridine)ruthenium(III) ([Ru(bipy)(3)](3+)) reagents and a recently developed colloidal manganese(IV) system. The selectivity of the permanganate reagent can be directed towards tyrosine or thiol compounds like cysteine, homocysteine and glutathione by manipulating reaction conditions (providing limits of detection of 4 nM tyrosine and 5 nM glutathione). Colloidal Mn(IV) produced measureable responses with all analytes, but was most suitable for tryptophan, tyrosine, thiols and disulfides, including α-lipoic acid and dihydrolipoic acid, for which the limits of detection were 30 nM and 20 nM, respectively. A stabilised form of [Ru(bipy)(3)](3+), prepared by oxidising [Ru(bipy)(3)](ClO(4))(2) in acetonitrile, exhibited similar selectivity to that of the conventional aqueous reagent. The [Ru(bipy)(3)](3+) reagent was effective for the detection of secondary amino acids such as proline and hydroxyproline, as well as the disulfide, homocystine.
Tailoring the fibre-to-matrix interface using click chemistry on carbon fibre surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TA00922D
Abstract: A convenient and effective strategy to control the surface chemistry of carbon fibres is presented, comprising electro-chemical reduction of aryl diazonium salts onto the surface, followed by ‘click chemistry’ to tether the desired surface characteristic of choice.
Precision milled flow-cells for chemiluminescence detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B914595H
Abstract: Novel flow-cells with integrated confluence points and reaction channels designed for efficient mixing of fast chemiluminescence systems were constructed by machining opposing sides of a polymer chip and sealing the channels with transparent epoxy-acetate films. A hole drilled through the chip provided the conduit from the confluence point on one side to the centre of the reaction zone on the other side, allowing rapid presentation of the reacting mixture to the photodetector. The effectiveness of each flow-cell was evaluated by comparing the chemiluminescence intensity using flow injection analysis methodology, and examining the distribution of light emanating from the reaction zone (captured by photography in a dark room) when the reactants were continuously merged. Although previously reported chemiluminescence detectors constructed by machining channels into polymers have almost exclusively been prepared using transparent materials, we obtained far greater emission intensities using an opaque white chip with a thin transparent seal, which minimised the loss of light through surfaces not exposed to the photomultiplier tube. Furthermore, this approach enabled the exploration of reactor designs that could not be incorporated in traditional coiled-tubing flow-cells.
Electrochemiluminescent Peptide Nucleic Acid-Like Monomers Containing Ru(II)–Dipyridoquinoxaline and Ru(II)–Dipyridophenazine Complexes
Publisher: American Chemical Society (ACS)
Date: 31-10-2011
DOI: 10.1021/IC201911F
Abstract: A series of Ru(II)-peptide nucleic acid (PNA)-like monomers, [Ru(bpy)(2)(dpq-L-PNA-OH)](2+) (M1), [Ru(phen)(2)(dpq-L-PNA-OH)](2+) (M2), [Ru(bpy)(2)(dppz-L-PNA-OH)](2+) (M3), and [Ru(phen)(2)(dppz-L-PNA-OH)](2+) (M4) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, dpq-L-PNA-OH = 2-(N-(2-(((9H-fluoren-9-yl)methoxy)carbonylamino)ethyl)-6-(dipyrido[3,2-a:2',3'-c]phenazine-11-carboxamido)hexanamido)acetic acid, dppz-L-PNA-OH = 2-(N-(2-(((9H-fluoren-9-yl) methoxy)carbonylamino)ethyl)-6-(dipyrido[3,2-f:2',3'-h]quinoxaline-2-carboxamido)acetic acid) have been synthesized and characterized by IR and (1)H NMR spectroscopy, mass spectrometry, and elemental analysis. As is typical for Ru(II)-tris(diimine) complexes, acetonitrile solutions of these complexes (M1-M4) show MLCT transitions in the 443-455 nm region and emission maxima at 618, 613, 658, and 660 nm, respectively, upon photoexcitation at 450 nm. Changes in the ligand environment around the Ru(II) center are reflected in the luminescence and electrochemical response obtained from these monomers. The emission intensity and quantum yield for M1 and M2 were found to be higher than for M3 and M4. Electrochemical studies in acetonitrile show the Ru(II)-PNA monomers to undergo a one-electron redox process associated with Ru(II) to Ru(III) oxidation. A positive shift was observed in the reversible redox potentials for M1-M4 (962, 951, 936, and 938 mV, respectively, vs Fc(0/+) (Fc = ferrocene)) in comparison with [Ru(bpy)(3)](2+) (888 mV vs Fc(0/+)). The ability of the Ru(II)-PNA monomers to generate electrochemiluminescence (ECL) was assessed in acetonitrile solutions containing tripropylamine (TPA) as a coreactant. Intense ECL signals were observed with emission maxima for M1-M4 at 622, 616, 673, and 675 nm, respectively. At an applied potential sufficiently positive to oxidize the ruthenium center, the integrated intensity for ECL from the PNA monomers was found to vary in the order M1 (62%) > M3 (60%) > M4 (46%) > M2 (44%) with respect to [Ru(bpy)(3)](2+) (100%). These findings indicate that such Ru(II)-PNA bioconjugates could be investigated as multimodal labels for biosensing applications.
Analytically useful blue chemiluminescence from a water-soluble iridium(iii) complex containing a tetraethylene glycol functionalised triazolylpyridine ligand
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6AN00141F
Abstract: The first highly water soluble, blue-luminescent iridium( iii ) complex for chemiluminescence detection is presented.
Chemiluminescence detection of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and related nitramine explosives
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.TALANTA.2011.11.051
Abstract: A simple controlled chemical reduction of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and related nitramine compounds with zinc amalgam generates species that elicit intense chemiluminescence with tris(2,2'-bipyridine)ruthenium(III), which extends this widely utilised chemiluminescence reagent to a new class of analyte and presents a sound chemical basis for a screening test for nitramine high explosives. Examination of the chemiluminescence profiles under stopped-flow conditions revealed contributions from multiple transient species formed in the initial reduction step.
New perspectives on the annihilation electrogenerated chemiluminescence of mixed metal complexes in solution
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6SC01570K
Abstract: We examine energy transfer and quenching within annihilation ECL systems comprising mixed metal-complexes in solution, and show the dependence of the emission intensities on luminophore concentration and the applied potentials.
Considering the chemical energy requirements of the tri-n-propylamine co-reactant pathways for the judicious design of new electrogenerated chemiluminescence detection systems
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5AN01462J
Abstract: A simple graphical approach to characterise the energetically feasible electrogenerated chemiluminescence (ECL) reaction pathways with tri- n -propylamine is discussed.
Chemiluminescence spectra for the oxidation of sulphite in the presence of fluorescent and non-fluorescent enhancers
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.ACA.2009.06.013
Abstract: The spectral distribution of chemiluminescence provides key evidence in the elucidation of the reaction mechanism and emitting species. We have collected chemiluminescence spectra for the oxidation of sodium sulphite and captopril in the presence of a range of fluorescent and non-fluorescent enhancers. This evidence was used to evaluate several previously proposed light-producing pathways, and revealed some new approaches to enhance the chemiluminescent oxidation of sulphite and thiol compounds. Chemiluminescence reactions between sulphite and permanganate produce two potential emitters: one derived from the oxidation of sulphite (in some cases via energy transfer to a more efficient luminophore) and another derived from the reduction of permanganate. This second light-producing pathway is rarely considered in discussions on the chemiluminescent oxidation of sulphite, but can make a significant contribution to the overall emission. Non-fluorescent enhancers of sulphite chemiluminescence result in several distinct spectral distributions and, contrary to previous postulation, these reactions are unlikely to lead to the same emitting species. Non-fluorescent enhancers of sulphite chemiluminescence can also significantly increase the weak emission from the oxidation of thiol compounds such as captopril.
Selective determination of amino acids using flow injection analysis coupled with chemiluminescence detection
Publisher: Elsevier BV
Date: 03-2003
Acidic potassium permanganate as a chemiluminescence reagent—A review
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1016/J.ACA.2007.08.027
Abstract: A critical and comprehensive review of acidic potassium permanganate chemiluminescence is presented. This includes discussion on reaction conditions, the influence of enhancers such as polyphosphates, formaldehyde and sulfite, the relationship between analyte structure and chemiluminescence intensity, and the application of this chemistry to determine a wide variety of compounds, such as pharmaceuticals, biomolecules, antioxidants, illicit drugs, pesticides and pollutants. Previous proposals for the nature of the emitting species are re-evaluated in light of recent evidence.
Chemiluminescence from the oxidation of urea and ammonia with hypobromite and N-bromosuccinimide
Publisher: Elsevier BV
Date: 08-10-2004
DOI: 10.1016/J.TALANTA.2004.02.031
Abstract: The spectral distribution for the chemiluminescent oxidation of ammonia with hypobromite is significantly different to that for the oxidation of ammonia with N-bromosuccinimide. Therefore, in contrast to the assumptions of several authors, the action of N-bromosuccinimide is not solely derived from the in situ formation of hypobromite. Neither the oxidation of urea with hypobromite nor the oxidation of urea with N-bromosuccinimide involves an initial hydrolysis of urea to ammonia in the alkaline solution. However, these two reactions lead to a common emitter. The addition of xanthene dyes, such as dichlorofluorescein, enhance the chemiluminescence intensity by energy transfer to the efficient fluorophore, but reaction between the sensitiser and hypobromite can result in a significant increase in the background signal. A list of potential interferences has been compiled particular attention was paid to guanidino compounds, as the chemiluminescence accompanying the oxidation of this functional group has not been previously discussed.
The use of parallel segmented outlet flow columns for enhanced mass spectral sensitivity at high chromatographic flow rates
Publisher: Wiley
Date: 02-03-2012
DOI: 10.1002/RCM.6176
Abstract: Speed of analysis is a significant limitation to current high-performance liquid chromatography/mass spectrometry (HPLC/MS) and ultra-high-pressure liquid chromatography (UHPLC)/MS systems. The flow rate limitations of MS detection require a compromise in the chromatographic flow rate, which in turn reduces throughput, and when using modern columns, a reduction in separation efficiency. Commonly, this restriction is combated through the post-column splitting of flow prior to entry into the mass spectrometer. However, this results in a loss of sensitivity and a loss in efficiency due to the post-extra column dead volume. A new chromatographic column format known as 'parallel segmented flow' involves the splitting of eluent flow within the column outlet end fitting, and in this study we present its application on a HPLC electrospray ionization time-of-flight mass spectrometer. Using parallel segmented flow, column flow rates as high as 2.5 mL/min were employed in the analysis of amino acids without post-column splitting to the mass spectrometer. Furthermore, when parallel segmented flow chromatography columns were employed, the sensitivity was more than twice that of conventional systems with post-column splitting when the same volume of mobile phase was passed through the detector. These finding suggest that this type of column technology will particularly enhance the capabilities of modern LC/MS enabling both high-throughput and sensitive mass spectral detection.
Self-enhanced multicolor electrochemiluminescence by competitive electron-transfer processes
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0SC00853B
Abstract: Controlling electrochemiluminescence (ECL) color(s) is crucial for many applications ranging from multiplexed bioassays to ECL microscopy.
The emitting species formed by the oxidation of hydrazides with hypohalites or N-halosuccinimides
Publisher: Wiley
Date: 07-2004
DOI: 10.1002/BIO.774
Abstract: The chemiluminescence accompanying the oxidation of salicylic hydrazide (2-hydroxybenzoic acid hydrazide) with hypochlorite, hypobromite, N-chlorosuccinimide, N-bromosuccinimide or hydrogen peroxide with cobalt(II) matched the photoluminescence emission of salicylic acid. In a related reaction, the oxidation of a mixture of isoniazid and ammonia, a synergistic effect was observed. The chemiluminescence spectrum for this reaction matches that accompanying the oxidation of the hydrazide, rather than the oxidation of ammonia. These results were used to assess mechanisms proposed by previous authors.
Simultaneous control of spectroscopic and electrochemical properties in functionalised electrochemiluminescent tris(2,2′-bipyridine)ruthenium(ii) complexes
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0AN00952K
Abstract: Using a combination of electrochemical, spectroscopic and computational techniques, we have explored the fundamental properties of a series of ruthenium diimine complexes designed for coupling with other molecules or surfaces for electrochemiluminescence (ECL) sensing applications. With appropriate choice of ligand functionality, it is possible to manipulate emission wavelengths while keeping the redox ability of the complex relatively constant. DFT calculations show that in the case of electron withdrawing substituents such as ester or amide, the excited state is located on the substituted bipyridine ligand whereas in the case of alkyl functionality it is localised on a bipyridine. The factors that dictate annihilation ECL efficiency are interrelated. For ex le, the same factors that determine ΔG for the annihilation reaction (i.e. the relative energies of the HOMO and LUMO) have a corresponding effect on the energy of the excited state product. As a result, most of the complexes populate the excited state with an efficiency (Φ(ex)) of close to 80% despite the relatively wide range of emission maxima. The quantum yield of emission (Φ(p)) and the possibility of competing side reactions are found to be the main determinants of ECL intensity.
Electrogenerated chemiluminescence of tris(2,2′ bipyridine)ruthenium(ii ) using common biological buffers as co-reactant, pH buffer and supporting electrolyte
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5AN01216C
Abstract: A series of aliphatic tertiary amines commonly used to buffer the pH in biological experiments, were examined as alternative, non-toxic co-reactants for electrogenerated chemiluminescence.
Chemiluminescence detection of opium poppy (Papaver somniferum) alkaloids
Publisher: Elsevier BV
Date: 11-2008
DOI: 10.1016/J.JPBA.2008.06.022
Abstract: A review with 98 references. The determination of the opium poppy (Papaver somniferum) alkaloids and their semi-synthetic derivatives has important applications in industrial process monitoring, clinical analysis and forensic science. Liquid-phase chemiluminescence reagents such as tris(2,2'-bipyridyl)ruthenium(II) and acidic potassium permanganate exhibit remarkable sensitivity and complementary selectivity for many P. somniferum alkaloids, which has been exploited in the development of a range of analytical procedures using flow analysis, high-performance liquid chromatography, capillary electrophoresis and microfluidic instrumentation.
Copper as a target for prostate cancer therapeutics: copper-ionophore pharmacology and altering systemic copper distribution.
Publisher: Impact Journals, LLC
Date: 09-05-2016
Electrochemiluminescence Amplification in Bead-Based Assays Induced by a Freely Diffusing Iridium(III) Complex
Publisher: American Chemical Society (ACS)
Date: 26-01-2023
Enhancing permanganate chemiluminescence detection for the determination of glutathione and glutathione disulfide in biological matrices
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4AN00255E
Abstract: Formaldehyde has a dramatic enhancing effect on not only the sensitivity but also the selectivity of permanganate chemiluminescence detection towards thiol compounds, including glutathione – an important biomarker of oxidative stress.
High-performance liquid chromatography with post-column 2,2′-diphenyl-1-picrylhydrazyl radical scavenging assay: Methodological considerations and application to complex samples
Publisher: Elsevier BV
Date: 08-2010
DOI: 10.1016/J.ACA.2010.06.041
Abstract: An improved post-column 2,2'-diphenyl-1-picrylhydrazyl (DPPH*) radical scavenging assay for the screening of antioxidants in complex matrices was developed. Experimental parameters believed to be influential to DPPH* response were studied in a univariate approach. Optimum conditions were found to be: 5 x 10(-5) M DPPH* reagent prepared in a 75% methanol: 25% 40 mM citric acid-sodium citrate buffer (pH 6) solution, degassed with nitrogen reaction coil of 2 m x 0.25 mm i.d. PEEK tubing detection at 521 nm analysis at room temperature. The analytical utility of this protocol was evaluated by screening for antioxidants in thyme and green tea, in comparison with two commonly employed methodologies.
Screening for antioxidants in complex matrices using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.ACA.2010.10.046
Abstract: The use of high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection to screen for antioxidants in complex plant-derived s les was evaluated in comparison with two conventional post-column radical scavenging assays (2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS(+))). In this approach, acidic potassium permanganate can react with readily oxidisable compounds (potential antioxidants), post-column, to produce chemiluminescence. Using flow injection analysis, experimental parameters that afforded the most suitable permanganate chemiluminescence signal for a range of known antioxidants were studied in a univariate approach. Optimum conditions were found to be: 1×10(-3)M potassium permanganate solution containing 1% (w/v) sodium polyphosphates adjusted to pH 2 with sulphuric acid, delivered at a flow rate of 2.5 mL min(-1) per line. Further investigations showed some differences in detection selectivity between HPLC with the optimised post-column permanganate chemiluminescence detection and DPPH and ABTS(+) assays towards antioxidant standards. However, permanganate chemiluminescence detection was more sensitive. Moreover, screening for antioxidants in green tea, cranberry juice and thyme using potassium permanganate chemiluminescence offers several advantages over the traditional DPPH and ABTS(+) assays, such as faster reagent preparation and superior stability simpler post-column reaction manifold and greater compatibility with fast chromatographic separations using monolithic columns.
Selectivity and potential interference from phenolic compounds in chemiluminescence methods for the determination of synephrine
Publisher: Wiley
Date: 11-09-2009
DOI: 10.1002/BIO.1070
Abstract: Three recently reported chemiluminescence methods (based on reactions with alkaline luminol and hexacyanoferrate(III) acidic cerium(IV) and rhodamine B and acidic permanganate with polyphosphates) for the determination of synephrine were re-evaluated in terms of their selectivity towards this analyte in comparison to other phenolic compounds. A fourth reagent system, acidic soluble manganese(IV) and formaldehyde, was also examined. Each set of reagents was sensitive towards synephrine (limits of detection were 3 x 10(-9), 5 x 10(-8), 1 x 10(-8) and 1 x 10(-8) mol/L, respectively) but also responded with numerous other phenolic compounds, including some that are present in citrus fruit extracts, dietary supplements and/or biological fluids. It is therefore recommended that the determination of synephrine in these matrices should incorporate physical separation of s le components (e.g. chromatography or electrophoresis). In more general terms, this study illustrates that accurate percentage recoveries for an analyte in spiked s les (without validation against another analytical method) are insufficient to confirm the analytical utility of new flow-injection analysis (FIA) procedures.
Chemiluminescence detection of MDMA in street drug samples using tris(2,2′-bipyridine)ruthenium(III)
Publisher: Wiley
Date: 09-03-2015
DOI: 10.1002/DTA.1780
Abstract: Tris(2,2'-bipyridine)ruthenium(II) chemiluminescence was investigated for the detection of 3,4-methylenedioxymeth hetamine (MDMA) and several related compounds in street drug s les. Optimization using flow injection analysis showed that the selectivity of the reagent can be targeted towards the detection of secondary amines by altering the pH of the reaction environment. The greater selectivity of this mode of detection, compared to UV-absorbance, reduces the probability of false positive results from interfering compounds. The detection limit for MDMA under these conditions was 0.48 μM. A HPLC method incorporating post-column tris(2,2'-bipyridine)ruthenium(II) chemiluminescence detection was applied to the determination of MDMA in five street drug s les. The results obtained were in good agreement with quantification performed using traditional UV-absorbance detection, which demonstrates the viability of this method for confirmatory analysis of drug s les. This is the first report of tris(2,2'-bipyridine)ruthenium(II) chemiluminescence for the detection of MDMA and related hetamine derivatives.
Photoredox catalysis of intramolecular cyclizations with a reusable silica-bound ruthenium complex
Publisher: Wiley
Date: 07-05-2015
Rapid determination of Papaver somniferum alkaloids in process streams using monolithic column high-performance liquid chromatography with chemiluminescence detection
Publisher: Elsevier BV
Date: 07-2007
DOI: 10.1016/J.ACA.2007.06.044
Abstract: We have combined high-performance liquid chromatography (HPLC) separations using a monolithic column with acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection in a rapid and highly sensitive method to monitor the process of extracting opiate alkaloids from Papaver somniferum. Due to the high flow rates allowed with the monolithic column and the inherent selectivity of the chemiluminescence reactions, the four predominant alkaloids--morphine, codeine, oripavine and thebaine--were determined in less than 2 min. The results obtained with numerous process s les compared favourable with those of the standard HPLC methodology. Limits of detection were 1x10(-10) M, 5x10(-10) M, 5x10(-10) M and 1x10(-9) M, for morphine, codeine, oripavine and thebaine, respectively.
Chemiluminescence methods for the determination of ofloxacin
Publisher: Elsevier BV
Date: 06-2005
Chemiluminescence detection of piperazine designer drugs and related compounds using tris(2,2′-bipyridine)ruthenium(III)
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.TALANTA.2013.08.029
Abstract: We present an exploration of the chemiluminescence from reactions of benzylpiperazines and phenylpiperazines with tris(2,2'-bipyridine)ruthenium(III). The selectivity of the reagent towards these compounds was found to be highly dependent upon the pH of the solution, and the relative emission intensity was strongly influenced by electron donating or withdrawing substituents on the phenyl or benzyl ring. In spite of previous investigations showing poor responses for aromatic-substituted amines (compared to their aliphatic amine counterparts), intense emissions were observed with phenylpiperazines under acidic conditions, particularly those with halogen or trifluoromethyl substituents on the aromatic ring. Buffered alkaline conditions provided much broader selectivity for the detection of both phenylpiperazine and benzylpiperazine compounds, which we have applied to a rapid HPLC procedure for the determination of piperazines of forensic interest in 'party pill' s les.
Comprehensive sample analysis using high performance liquid chromatography with multi-detection
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.ACA.2013.08.013
Abstract: Herein we assess the separation space offered by a liquid chromatography system with an optimised uni-dimensional separation for the determination of the key chemical entities in the highly complex matrix of a tobacco leaf extract. Multiple modes of detection, including UV-visible absorbance, chemiluminescence (acidic potassium permanganate, manganese(IV), and tris(2,2'-bipyridine)ruthenium(III)), mass spectrometry and DPPH radical scavenging were used in an attempt to systematically reduce the data complexity of the s le whilst obtaining a greater degree of molecule-specific information. A large amount of chemical data was obtained, but several limitations in the ability to assign detector responses to particular compounds, even with the aid of complementary detection systems, were observed. Thirty-three compounds were detected via MS on the tobacco extract and 12 out of 32 compounds gave a peak height ratio (PHR) greater than 0.33 on one or more detectors. This paper serves as a case study of these limitations, illustrating why multidimensional chromatography is an important consideration when developing a comprehensive chemical detection system.
Iridium(iii ) N-heterocyclic carbene complexes: an experimental and theoretical study of structural, spectroscopic, electrochemical and electrogenerated chemiluminescence properties
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4DT03378G
Abstract: Theoretical and experimental studies of a series of iridium N-heterocyclic carbene complexes.
Understanding Electrogenerated Chemiluminescence Efficiency in Blue-Shifted Iridium(III)-Complexes: An Experimental and Theoretical Study
Publisher: Wiley
Date: 03-03-2014
Abstract: Compared to tris(2-phenylpyridine)iridium(III) ([Ir(ppy)3 ]), iridium(III) complexes containing difluorophenylpyridine (df-ppy) and/or an ancillary triazolylpyridine ligand [3-phenyl-1,2,4-triazol-5-ylpyridinato (ptp) or 1-benzyl-1,2,3-triazol-4-ylpyridine (ptb)] exhibit considerable hypsochromic shifts (ca. 25-60 nm), due to the significant stabilising effect of these ligands on the HOMO energy, whilst having relatively little effect on the LUMO. Despite their lower photoluminescence quantum yields compared with [Ir(ppy)3 ] and [Ir(df-ppy)3 ], the iridium(III) complexes containing triazolylpyridine ligands gave greater electrogenerated chemiluminescence (ECL) intensities (using tri-n-propylamine (TPA) as a co-reactant), which can in part be ascribed to the more energetically favourable reactions of the oxidised complex (M(+) ) with both TPA and its neutral radical oxidation product. The calculated iridium(III) complex LUMO energies were shown to be a good predictor of the corresponding M(+) LUMO energies, and both HOMO and LUMO levels are related to ECL efficiency. The theoretical and experimental data together show that the best strategy for the design of efficient new blue-shifted electrochemiluminophores is to aim to stabilise the HOMO, while only moderately stabilising the LUMO, thereby increasing the energy gap but ensuring favourable thermodynamics and kinetics for the ECL reaction. Of the iridium(III) complexes examined, [Ir(df-ppy)2 (ptb)](+) was most attractive as a blue-emitter for ECL detection, featuring a large hypsochromic shift (λmax =454 and 484 nm), superior co-reactant ECL intensity than the archetypal homoleptic green and blue emitters: [Ir(ppy)3 ] and [Ir(df-ppy)3 ] (by over 16-fold and threefold, respectively), and greater solubility in polar solvents.
A screening test for heroin based on sequential injection analysis with dual-reagent chemiluminescence detection
Publisher: Elsevier BV
Date: 30-07-2008
DOI: 10.1016/J.TALANTA.2008.04.012
Abstract: A sequential injection analysis procedure with dual-reagent chemiluminescence detection was applied to the screening of street drug seizure s les for the presence of heroin. The chemiluminescence reagents (acidic potassium permanganate and tris(2,2'-bipyridine)ruthenium(III)) were aspirated from either side of a s le aliquot that was sufficiently large to prevent interdispersion of the reagent zones, and therefore two different chemical reactions could be performed simultaneously at either end of the s le zone. The presence of heroin in seizure s les was indicated by a strong response with the tris(2,2'-bipyridine)ruthenium(III) reagent and confirmed by a significant increase in the response with the permanganate reagent when the s le was treated with sodium hydroxide to hydrolyse the heroin to morphine. Nicomorphine (a morphine-derived pharmaceutical) was synthesised and tested under the same conditions. The responses with the permanganate reagent were similar to those for heroin, which supports the proposed chemical basis for the test. However, the responses with tris(2,2'-bipyridine)ruthenium(III) were far lower for nicomorphine than heroin (approximately 5-fold for the s les that had not been hydrolysed).
A comparison of novel organoiridium(III) complexes and their ligands as a potential treatment for prostate cancer
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.EJMECH.2015.12.035
Abstract: A range of 1,4-substituted 2-pyridyl-N-phenyl triazoles were synthesised and evaluated for their antiproliferative properties against lymph node cancer of the prostate (LNCaP) and bone metastasis of prostate cancer (PC-3) cells. Excellent-to-low IC50 values were determined (5.6-250 μM), and a representative group of 4 ligands were then complexed to iridium(III) giving highly luminescent species. Re-evaluation of these compounds against both cell lines was then undertaken and improved potency (up to 72-fold) was observed, giving IC50 values of 0.36-11 μM for LNCaP and 0.85-5.9 μM for PC-3. Preliminary screens for in vivo toxicity were conducted using a zebrafish model showing a wide range of induced toxicity depending of the compound evaluated. Apoptosis and Caspase-3 levels were also determined and showed no statistical difference between some of the treated specimens and the controls. This study may identify novel therapeutic agents for advanced stage of prostate cancer in humans.
Chemiluminescence detectors for liquid chromatography
Publisher: Wiley
Date: 03-2011
DOI: 10.1002/DTA.132
Abstract: In this tutorial we describe the construction of chemiluminescence detectors for high performance liquid chromatography (HPLC), comprising the components required to deliver the chemiluminescence reagent, a coiled-tubing flow cell, photomultiplier tube and detector housing, and various options for data acquisition. We also discuss two state-of-the-art commercially available chemiluminescence detectors for HPLC and other flow analysis methodology.
A simple device for rapid quantification of cell number from equine buccal swab samples
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8AY00338F
Abstract: This device measures absorbance for the quantification of cell number from buccal swabs by exploiting dye transitions of Bradford's reagent.
Mechanism of Permanganate Chemiluminescence
Publisher: American Chemical Society (ACS)
Date: 07-04-2010
DOI: 10.1021/AC100363S
Abstract: Spectroscopic and synthetic methods have been exploited to deduce the mechanism for acidic potassium permanganate chemiluminescence. We have employed electron paramagnetic resonance (EPR) spectroscopy with a continuous flow assembly to monitor the formation of radical intermediates in real time generated from substrate oxidation by manganese(VII). These transient species react with manganese(III) in solution to produce the previously characterized manganese(II)* emission source. Using UV-vis, EPR, attenuated total reflection (ATR)-FT-IR, and chemiluminescence spectroscopies, we have established that there are two distinct enhancement mechanisms that in combination afford a 50-fold increase in emission intensity when the reaction is conducted in the presence of phosphate oligomers. In addition to preventing disproportionation of the manganese(III) precursor, the phosphate oligomers form protective "cagelike" structures around the manganese(II)* emitter, thus preventing nonradiative relaxation pathways.
Confirmation of the classic tris(2,2′-bipyridyl)ruthenium(II) and oxalate electrochemiluminescence mechanism using EPR spectroscopy
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CC11434D
Abstract: A chemically initiated adaptation of the classic [Ru(bipy)(3)](2+)/oxalate electrochemiluminescence coreactant system has revealed the elusive radical intermediates of the light-producing pathway. Oxalyl (HC(2)O(4)˙) and hydroxyformyl (HCO(2)˙) radicals have been captured on a quartz surface and characterised using EPR spectroscopy.
N-acetylcysteine (NAC) in schizophrenia resistant to clozapine: a double blind randomised placebo controlled trial targeting negative symptoms.
Publisher: Springer Science and Business Media LLC
Date: 15-09-2016
Mixed annihilation electrogenerated chemiluminescence of iridium(iii ) complexes
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP01737A
Abstract: The annihilation electrogenerated chemiluminescence of mixtures of Ir( iii ) complexes is eliminated by manipulating reduction potentials through subtle changes in ligand structure.
The determination of urea in wine - A review
Publisher: Hindawi Limited
Date: 07-2006
On-line generation of a colloidal manganese(IV) reagent for chemiluminescence detection
Publisher: Elsevier BV
Date: 07-2013
Chemiluminescence detection of arginine-containing peptides separated with monolithic high-performance liquid chromatography
Publisher: Elsevier BV
Date: 2005
Chemiluminescence from the Sakaguchi reaction
Publisher: Elsevier BV
Date: 06-2004
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