ORCID Profile
0000-0002-6238-3612
Current Organisation
University of Technology Sydney
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
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.
Medical Biotechnology | Biomedical Instrumentation | Medical Biotechnology Diagnostics (incl. Biosensors) | Forensic Chemistry | Other Chemical Sciences | Biological (Physical) Anthropology | Archaeological Science |
Diagnostic Methods | Veterinary Diagnostics | Scientific Instruments | National Security | Law Enforcement | Expanding Knowledge in Technology | Health Protection and/or Disaster Response
Publisher: Wiley
Date: 09-06-2020
DOI: 10.1002/DTA.2861
Abstract: The lucrative market of herbal remedies spurs r ant adulteration, particularly with pharmaceutical drugs and their unapproved analogues. A comprehensive screening strategy is, therefore, warranted to detect these adulterants and, accordingly, to safeguard public health. This study uses the data-dependent acquisition of liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS) to screen phosphodiesterase 5 (PDE5) inhibitors in herbal remedies using suspected-target and non-targeted strategies. For the suspected-target screening, we used a library comprising 95 PDE5 inhibitors. For the non-targeted screening, we adopted top-down and bottom-up approaches to flag novel PDE5 inhibitor analogues based on common fragmentation patterns. LC-QTOF-MS was optimised and validated for capsule and tablet dosage forms using 23 target analytes, selected to represent different groups of PDE5 inhibitors. The method exhibited excellent specificity and linearity with limit of detection and limit of quantification of <40 and 80 ng/mL, respectively. The accuracy ranged from 79.0% to 124.7% with a precision of <14.9% relative standard deviation. The modified, quick, easy, cheap, effective, rugged, and safe extraction provided insignificant matrix effect within -9.1%-8.0% and satisfactory extraction recovery of 71.5%-105.8%. These strategies were used to screen 52 herbal remedy s les that claimed to enhance male sexual performance. The suspected-target screening resulted in 33 positive s les, revealing 10 target analytes and 2 suspected analytes. Systematic MS and tandem MS interrogations using the non-targeted screening returned insignificant signals, indicating the absence of potentially novel analogues. The target analytes were quantified from 0.03 to 121.31 mg per dose of each s le. The proposed strategies ensure that all PDE5 inhibitors are comprehensively screened, providing a useful tool to curb the widespread adulteration of herbal remedies.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Wiley
Date: 10-11-2018
DOI: 10.1002/DTA.2300
Abstract: Chemical 'spot' tests are a presumptive illicit drug identification technique commonly used by law enforcement, border security personnel, and forensic laboratories. The simplicity, low cost, and rapid results afforded by these tests make them particularly attractive for presumptive identification globally. In this paper, we review the development of these long-established methods and discuss color test recommendations and guidelines. A search of the scientific literature revealed the chemical reactions occurring in many color tests are either not actively investigated or reported as unknown. Today, color tests face many challenges, from the appearance of new psychoactive substances to concerns regarding selectivity, sensitivity, and safety. Advances in technology have seen color test reagents used in digital image color analysis, solid sensors, and microfluidic devices for illicit drug detection. This summarizes current research and suggests the future of presumptive color testing.
Publisher: Wiley
Date: 17-12-2020
DOI: 10.1111/DMCN.14774
Abstract: To explore the cerebrospinal fluid (CSF) metabolite features in acute neuroinflammatory diseases and identify potential biomarkers to diagnose and monitor neuroinflammation. A cohort of 14 patients (five females, nine males mean [median] age 7y 9mo [9y], range 6mo–13y) with acute encephalitis (acute disseminated encephalomyelitis n =6, unknown suspected viral encephalitis n =3, enteroviral encephalitis n =2, seronegative autoimmune encephalitis n =2, herpes simplex encephalitis n =1) and age‐matched non‐inflammatory neurological disease controls ( n =14) were investigated using an untargeted metabolomics approach. CSF metabolites were analyzed with liquid chromatography coupled to high resolution mass spectrometry, followed by subsequent multivariate and univariate statistical methods. A total of 35 metabolites could be discriminated statistically between the groups using supervised orthogonal partial least squares discriminant analysis and analysis of variance. The tryptophan‐kynurenine pathway contributed nine key metabolites. There was a statistical increase of kynurenine, quinolinic acid, and anthranilic acid in patients with encephalitis, whereas tryptophan, 3‐hydroxyanthrnailic acid, and kynurenic acid were decreased. The nitric oxide pathway contributed four metabolites, with elevated asymmetric dimethylarginine and argininosuccinic acid, and decreased arginine and citrulline in patients with encephalitis. An increase in the CSF kynurenine/tryptophan ratio ( p 0.001), anthranilic acid/3‐hydroxyanthranilic acid ratio ( p 0.001), asymmetric dimethylarginine/arginine ratio ( p 0.001), and neopterin ( p 0.001) strongly predicted neuroinflammation. The combination of alterations in the tryptophan‐kynurenine pathway, nitric oxide pathway, and neopterin represent a useful potential panel for neuroinflammation and holds potential for clinical translation practice. The kynurenine/tryptophan and anthranilic acid/3‐hydroxyanthranilic acid ratios hold great potential as biomarkers of neuroinflammation. Elevation of the asymmetric dimethylarginine/arginine ratio in acute brain inflammation shows dysregulation of the nitric oxide pathway.
Publisher: Future Medicine Ltd
Date: 08-2017
Abstract: Aim: To assess the feasibility of the use of cannabidiol (CBD) for the management of cannabis withdrawal. Patients & methods: Eight participants were admitted to an in-patient detoxification facility for a 7-day open-label trial of CBD. Five participants received 600 mg of CBD and three participants received 1200 mg of CBD. Participants returned for a 28-day follow-up interview. Results & conclusion: CBD was well tolerated by all participants. Five completed the full treatment period and abstinence was maintained by four participants at day 28 follow-up. All those receiving the higher dose completed treatment and achieved abstinence at follow-up. This pilot study suggests that further exploration of CBD as a pharmacological adjunctive therapy for cannabis withdrawal and dependence is warranted. Registration ACTRN1261400024866.
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.FORSCIINT.2015.12.023
Abstract: Being marketed as "legal" smoking blends or mixtures, synthetic cannabinoids are abused widely owing to its cannabis-like effect. Due to the rapid introduction of new generation analogues of synthetic cannabinoids to escape from legislative/judicial control, the investigation of the metabolic pathways of these substances is of particular importance for drug control, abstinence and forensic toxicology purposes. In this study, the in vitro metabolism of JWH-018, JWH-073 and AM2201 by the fungus Cunninghamella elagans has been investigated with the purpose of validating its potential as a complementary model for investigating synthetic cannabinoid metabolism. JWH-018, JWH-073 and AM2201 were incubated for 72h with C. elegans. Detection of metabolites was based on liquid chromatography-tandem mass spectrometry and high resolution mass spectrometry analysis. C. elegans was found capable of producing the majority of the phase I metabolites observed in earlier in vitro and in vivo mammalian studies as a result of monohydroxylation, dihydroxylation, carboxylation, dehydrogenation, ketone formation, dihydrodiol formation, dihydrodiol formation with N-dealkylation and combinations thereof. C. elegans can thus be a useful and economic model for studying synthetic cannabinoid metabolism.
Publisher: Elsevier
Date: 2019
Publisher: Wiley
Date: 09-11-2017
DOI: 10.1002/DTA.2261
Abstract: Cocaine trafficking in the form of textile impregnation is routinely encountered as a concealment method. Raman spectroscopy has been a popular and successful testing method used for in situ screening of cocaine in textiles and other matrices. Quantitative analysis of cocaine in these matrices using Raman spectroscopy has not been reported to date. This study aimed to develop a simple Raman method for quantifying cocaine using atropine as the model analogue in various types of textiles. Textiles were impregnated with solutions of atropine in methanol. The impregnated atropine was extracted using less hazardous acidified water with the addition of potassium thiocyanate (KSCN) as an internal standard for Raman analysis. Despite the presence of background matrix signals arising from the textiles, the cocaine analogue could easily be identified by its characteristic Raman bands. The successful use of KSCN normalised the analyte signal response due to different textile matrix background interferences and thus removed the need for a matrix-matched calibration. The method was linear over a concentration range of 6.25-37.5 mg/cm
Publisher: Wiley
Date: 13-02-2014
DOI: 10.1002/RCM.6832
Abstract: Although hetamine-type substances (ATS) have been investigated extensively in recent years, scarce data is available on screening tests for piperazine analogues. The need for a universal technique capable of detecting an extensive range of drug compounds becomes increasingly important with the continued emergence of novel drug analogues. Desorption electrospray ionisation mass spectrometry (DESI-MS) is a technique that allows examination of compounds in drug materials directly from ambient surfaces. In this study, DESI-MS was utilised in the analysis of ATS including hetamine (AP), methyl hetamine (MA), 3,4-methylenedioxymethyl hetamine (MDMA), N,N-dimethyl hetamine (DMA), 4-methoxy hetamine (PMA) and 4-methoxymethyl hetamine (PMMA), and piperazine analogues including 1-benzylpiperazine (BZP), 1-[3-(trifluoromethyl)phenyl]piperazine (TFMPP), 1-(3-chlorophenyl)piperazine (mCPP) and 1-(4-methoxyphenyl)piperazine (MeOPP). Semi-porous polytetrafluoroethylene (PTFE or Teflon) sheets welled with a 3 mm hole punch were used to contain the 2 μL liquid s le (spot size 7 mm(2) ). The limits of detection (LODs) of these compounds using DESI-MS were determined to be in the range 0.02-2.80 µg/mm(2) . The intra-day and inter-day precision of the technique were <25% and <33%, respectively. DESI-MS was successful in determining the compound of interest and reaction by-products and impurities in the s les tested (such as 1,4-dibenzylpiperazine in BZP s les) with the exception of those present in trace amounts. The effects of common adulterants on the detectability of MA were evaluated. The addition of magnesium stearate to MA significantly enhanced the signal response. This work has demonstrated the applicability of DESI-MS in the screening and profiling of MDMA, PMMA, BZP, TFMPP, mCPP, MeOPP as well as other complex mixtures.
Publisher: Elsevier BV
Date: 11-1998
Publisher: Wiley
Date: 29-04-2022
DOI: 10.1002/WFS2.1461
Abstract: The analysis of drug material in the field is an important function of law enforcement agencies, forensic drug laboratories, and drug checking services. Portable testing techniques employed by these different groups range from inexpensive screening tools with low discriminating power, such as presumptive chemical color tests, to more sophisticated portable analytical techniques that behave as miniaturized versions of their laboratory counterparts, such as gas chromatography–mass spectrometry (GC–MS). Rapid non‐destructive analysis in the field and non‐laboratory environments is afforded by portable and handheld Fourier transform infrared (FTIR) spectrometers with little to no s le preparation, while handheld Raman analyzers have the added potential for drug material identification through sealed packaging using spatially offset Raman spectroscopy (SORS). Utilization of the most suitable testing technique for the given environment is demonstrated at international borders and airports wherein ion mobility spectroscopy (IMS) is frequently employed for the detection of drug (and explosive) residues owing to its ease of operation and rapid analysis. Advances in technology and materials have provided analysts with new portable testing techniques, including paper spray ionization–MS (PSI‐MS), an ambient MS technique that provides sensitive, rapid, and reliable analysis without the need for s le preparation steps. A growing area of research and interest in the development of sensitive and selective optical and electrochemical portable (bio)sensors for in‐field analysis of drug material indicates that new commercial sensors for drug detection will be available in the foreseeable future. This article is categorized under: Forensic Chemistry and Trace Evidence Controlled and Emerging Drug Compounds Forensic Chemistry and Trace Evidence Emerging Technologies and Methods Toxicology Drug Analysis
Publisher: Informa UK Limited
Date: 05-02-2014
Publisher: MyJove Corporation
Date: 05-02-2018
DOI: 10.3791/57045
Publisher: Springer Science and Business Media LLC
Date: 24-04-2012
DOI: 10.1007/S00216-012-6017-4
Abstract: 6-Monoacetylmorphine (6-MAM), being a unique metabolite of heroin, is routinely tested in urine s les to monitor heroin use. However, detection of 6-MAM-related opiates such as morphine is known to be affected by in vitro urine adulteration using oxidizing adulterants such as potassium nitrite. This study aimed to investigate the fate of 6-MAM after exposure to nitrite and to identify any formed oxidation products that may potentially be used for monitoring heroin abuse despite nitrite adulteration. Potassium nitrite (0.05 M and 0.6 M) was reacted with 6-MAM (5-10,000 ng/mL) in both water and blank urine with pH adjusted to range from 3 to 8. Following reaction at room temperature for varying periods, the reaction mixtures were monitored by both the CEDIA® Heroin Metabolite (6-AM) immunoassay and liquid chromatography-mass spectrometry (LC-MS) methods. Structural elucidation of the isolated oxidation products was based on mass spectrometry and nuclear magnetic resonance spectroscopic evidence. Nitrite, under acidic environment (pH<7), was shown to be effective in masking the detection of 6-MAM by both the CEDIA® immunoassay and the LC-MS methods. 2-Nitro-6-monoacetylmorphine (2-nitro-MAM) was identified as the sole oxidation product, which remained detectable in urine for at least 11 days under the experimental conditions investigated. 2-Nitro-MAM was detectable in a urine s le of a heroin user after nitrite exposure. 2-Nitro-MAM has shown potential to serve as a marker for monitoring heroin abuse when urine is adulterated with nitrite. Certification of 2-nitro-MAM reference standard for further development of its quantitative testing methods is thus warranted.
Publisher: MDPI AG
Date: 26-01-2021
DOI: 10.3390/S21030810
Abstract: Surface-enhanced Raman spectroscopy (SERS) technology is an attractive method for the prompt and accurate on-site screening of illicit drugs. As portable Raman systems are available for on-site screening, the readiness of SERS technology for sensing applications is predominantly dependent on the accuracy, stability and cost-effectiveness of the SERS strip. An atmospheric-pressure plasma-assisted chemical deposition process that can deposit an even distribution of nanogold particles in a one-step process has been developed. The process was used to print a nanogold film on a paper-based substrate using a HAuCl4 solution precursor. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that the gold has been fully reduced and that subsequent plasma post-treatment decreases the carbon content of the film. Results for cocaine detection using this substrate were compared with two commercial SERS substrates, one based on nanogold on paper and the currently available best commercial SERS substrate based on an Ag pillar structure. A larger number of bands associated with cocaine was detected using the plasma-printed substrate than the commercial substrates across a range of cocaine concentrations from 1 to 5000 ng/mL. A detection limit as low as 1 ng/mL cocaine with high spatial uniformity was demonstrated with the plasma-printed substrate. It is shown that the plasma-printed substrate can be produced at a much lower cost than the price of the commercial substrate.
Publisher: Elsevier BV
Date: 08-2017
Publisher: Oxford University Press (OUP)
Date: 11-2012
Abstract: A simple and sensitive GC/MS method was developed for the detection of patulin in apple juice. The method utilized a common laboratory chemical, 3-nitrobenzyl alcohol, as an internal standard. The calibration curve, ranging from 5 to 100 μg/L, showed good linearity with a correlation coefficient of 0.999. The LOD and LOQ were 2 and 5 μg/L, respectively. The significant advantage of the method was removal of the need for in-house synthesis of appropriate internal standards as reported by other researchers. The method also eliminated the need for careful s le preparation procedures, as outlined in some AOAC methods in which no internal standard was utilized. The streamlined extraction process and the improved sensitivity warrant the developed method to be a useful alternative for drug testing laboratories, especially those with large specimen volume and throughput to determine patulin levels in apple juice.
Publisher: Wiley
Date: 09-12-2021
DOI: 10.1002/DTA.2976
Abstract: The constant evolution of the illicit drug market makes the identification of unknown compounds problematic. Obtaining certified reference materials for a broad array of new analogues can be difficult and cost prohibitive. Machine learning provides a promising avenue to putatively identify a compound before confirmation against a standard. In this study, machine learning approaches were used to develop class prediction and retention time prediction models. The developed class prediction model used a naïve Bayes architecture to classify opioids as belonging to either the fentanyl analogues, AH series or U series, with an accuracy of 89.5%. The model was most accurate for the fentanyl analogues, most likely due to their greater number in the training data. This classification model can provide guidance to an analyst when determining a suspected structure. A retention time prediction model was also trained for a wide array of synthetic opioids. This model utilised Gaussian process regression to predict the retention time of analytes based on multiple generated molecular features with 79.7% of the s les predicted within ±0.1 min of their experimental retention time. Once the suspected structure of an unknown compound is determined, molecular features can be generated and input for the prediction model to compare with experimental retention time. The incorporation of machine learning prediction models into a compound identification workflow can assist putative identifications with greater confidence and ultimately save time and money in the purchase and/or production of superfluous certified reference materials.
Publisher: Wiley
Date: 19-07-2021
DOI: 10.1002/DTA.2894
Abstract: The use of illicit drugs across the world causes issues for users, healthcare workers and the public. Therefore, rapid and reliable onsite testing methods to detect these drugs are required. In this study, seven commercial surface-enhanced Raman spectroscopy (SERS) substrates A-G were compared for the analysis of cocaine. These substrates were compared using scanning electron microscopy to study the surface structure and Raman spectroscopy and to determine if there was any enhancement of the cocaine bands. Substrate B provided the best enhancement of known cocaine vibrational bands, allowing the detection down to concentrations of 1 ng/mL in standards and 10 ng/mL extracted from the oral fluid. The results showed that SERS is an ideal method for future rapid onsite analysis of illicit drugs in oral fluid. Commercial SERS substrates were compared for the analysis of cocaine. Substrate B provided the best result and was further tested with lower concentrations and extracts from the oral fluid. The application to oral fluid testing could prove useful for future onsite analysis.
Publisher: Wiley
Date: 17-06-2014
DOI: 10.1002/DTA.1684
Abstract: Desorption electrospray ionization - mass spectrometry (DESI-MS) is a useful technique for the qualitative analysis of compounds found in seized drug material. In this study, DESI-MS was utilized in the screening analysis of illicit cocaine s les. The technique was also applied to the geographical origin determination of these s les. The limit of detection was determined to be 24.3 µg (or 3.47 µg/mm(2) ) and the analysis time was less than 1 minute per s le. The intra-day and inter-day precision for the detection of cocaine was 11 % and 42 %, respectively therefore the quantitative data provided by DESI-MS was limited in its use for accurate determination of cocaine concentration in a s le. Using the quadrupole time-of-flight (QTOF) mass spectrometer, the presence of cocaine and impurities detected were confirmed by accurate tandem MS data. The qualitative chemical profiles obtained using DESI-MS were compared to two popular analysis techniques, GC-MS and LC-MS. The effects of a range of adulterants including caffeine, procaine, levamisole, lignocaine, paracetamol, and atropine on the detectability of cocaine were also investigated. It was found that the addition of these adulterants in a cocaine s le did not prevent the detection of the analyte itself (there was slight enhancement in some s les), which was useful in drug detection. The detection of truxillines in the seized s les by DESI-MS aided in the preliminary determination of geographical origin, i.e., Bolivian, Peruvian or Colombian leaf origin. The application of DESI-MS to the qualitative analysis and screening of seized cocaine s les demonstrates the potential and applicability of the technique to the fast chemical profiling of illicit s les.
Publisher: Wiley
Date: 15-07-2021
DOI: 10.1002/DTA.2893
Abstract: Synthetic opioids are a class of compounds that are of particular concern due to their high potency and potential health impacts. With the relentless emergence of new synthetic opioid derivatives, non-targeted screening strategies are required that do not rely on the use of library spectra or reference materials. In this study, product ion searching, and Kendrick mass defect analysis were investigated for non-targeted screening of synthetic opioids. The estimated screening cut-offs for these techniques ranged between 0.05 and 0.1 ng/mL. These techniques were designed to not be reliant on a particular vendor's software, meaning that they can be applied to existing drug screening protocols, without requiring the development and validation of new analytical procedures. The efficacy of the developed techniques was tested through blind trials, with spiked s les inserted amongst authentic plasma s les, which demonstrated the usefulness of these methods for high-throughput screening. The use of a non-targeted screening workflow that contains complementary techniques can increase the likelihood of detecting compounds of interest within a s le, as well as the confidence in detections that are made.
Publisher: Oxford University Press (OUP)
Date: 09-06-2017
Publisher: Springer Science and Business Media LLC
Date: 20-06-2017
DOI: 10.1007/S00216-017-0441-4
Abstract: The proliferation of new psychoactive substances (NPS) in recent years has resulted in the development of numerous analytical methods for the detection and identification of known and unknown NPS derivatives. High-resolution mass spectrometry (HRMS) has been identified as the method of choice for broad screening of NPS in a wide range of analytical contexts because of its ability to measure accurate masses using data-independent acquisition (DIA) techniques. Additionally, it has shown promise for non-targeted screening strategies that have been developed in order to detect and identify novel analogues without the need for certified reference materials (CRMs) or comprehensive mass spectral libraries. This paper reviews the applications of HRMS for the analysis of NPS in forensic drug chemistry and analytical toxicology. It provides an overview of the s le preparation procedures in addition to data acquisition, instrumental analysis, and data processing techniques. Furthermore, it gives an overview of the current state of non-targeted screening strategies with discussion on future directions and perspectives of this technique. Graphical Abstract Missing the bullseye - a graphical respresentation of non-targeted screening. Image courtesy of Christian Alonzo.
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.FORSCIINT.2011.01.045
Abstract: A fast and sensitive method was developed for detecting delta-9-tetrahydrocannabinol (THC) in oral fluid by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method is suitable for s les of small volume and low concentration. For method development and validation, neat oral fluid (200 μL) spiked with THC and d(3)-THC (internal standard) was extracted via liquid-liquid extraction (LLE). The LLE method had an extraction efficiency of 75% with no significant matrix effects observed in either diluted or neat oral fluid s les. LC was performed on a Zorbax Eclipse XDB-C18 Rapid Resolution HT column (2.1 mm × 50 mm, 1.8 μm particle size) with positive electrospray ionisation and selected reaction monitoring. The total run time was an efficient 3.5 min in isocratic elution mode. The limit of quantification was 1 ng/mL and the analysis was linear over the range of 1-500 ng/mL with a correlation coefficient of 0.9998. The imprecision (RSD) of the method was 13% and inaccuracy (MRE) was 4%. The method was subsequently applied to two neat oral fluid s les taken from a chronic cannabis smoker. It was also applied to buffer diluted residual oral fluid s les (n=48) collected using the Cozart RapiScan(®) system through the Roadside Drug Testing Program (RDTP) in NSW, Australia. A stability study was performed that revealed freezing or refrigerating resulted in comparable decreases in THC recovery from neat oral fluid at the end of two weeks of storage. Storage at room temperature even for one day invoked significant losses and is not recommended.
Publisher: Wiley
Date: 05-04-2022
DOI: 10.1002/DTA.3264
Abstract: Equine urine analysis has evolved over time to detect thousands of urinary compounds for doping control in the horse racing industry. The longitudinal assessment of 3‐methoxytyramine to tyramine ratio (3‐MT/T) values in equine urine by GC–MS profiling was investigated to support the Racing NSW Equine Biological Passport (EBP) for detection of dopaminergic manipulation in racehorses. This involved comparison of routine urine s les to administration studies of Sinemet , a common Parkinson's disease medication containing levodopa. Using an endogenous reference compound (ERC) in a urinary ratio enabled greater confidence to provide intelligence of pharmaceutical manipulation as distinct from physiological variation. Population reference limits (PRLs) of 776 ng/ml for urinary 3‐MT and 5.3 for 3‐MT/T, together with the use of in idual reference limits (IRLs), are proposed.
Publisher: Oxford University Press (OUP)
Date: 11-11-2020
Publisher: Wiley
Date: 03-03-2021
DOI: 10.1002/DTA.3021
Abstract: The emergence of novel doping agents is a continuous issue for analysts who aim to maintain the integrity of horseracing together with the well-being and safety of the animals and riders involved. Untargeted mass spectrometric analysis presents a potential improvement for antidoping as it enables the detection of compounds being indirectly affected by an administered drug. In this study, liquid chromatography-high-resolution mass spectrometry was used to investigate a 12-horse administration study of the synthetic opioid, butorphanol. A mass spectrometric workflow capable of detecting metabolic differences for an extended period of time was successfully developed. This proof-of-concept study demonstrates the potential of untargeted workflows to provide a list of biomarkers of exposure and effect that are indicative of drug administration which may be implemented into routine testing for improved doping control.
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.TALANTA.2019.05.078
Abstract: As a widely consumed beverage, coffee tends to be a target for intentional adulteration. This study describes the application of modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) coupled to liquid chromatography-high-resolution mass spectrometry (LC-HRMS) for simultaneous screening, identification, and quantification of undeclared phosphodiesterase 5 (PDE5) inhibitors in instant coffee premixes (ICPs). The mass spectrometer was operated in auto MS/MS acquisition for simultaneous MS and MS/MS experiments. Qualitative establishments from the suspected-target screening and targeted identification processes led to an unambiguous analyte assignment from the protonated molecule ([M+H]
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4NJ01478B
Abstract: Adulteration of urine with permanganate can lead to depletion of testosterone and formation of new reaction products (4α,5α- and 4β,5β-dihydroxytestosterone).
Publisher: Wiley
Date: 08-03-2017
DOI: 10.1002/DTA.2171
Abstract: Hallucinogenic phenethylamines such as 2,5-dimethoxyphenethylamines (2C-X) and their N-(2-methoxybenzyl) derivatives (25X-NBOMe) have seen an increase in novel analogues in recent years. These rapidly changing analogues make it difficult for laboratories to rely on traditional targeted screening methods to detect unknown new psychoactive substances (NPS). In this study, twelve 2C-X, six 2,5-dimethoxy hetamines (DOX), and fourteen 25X-NBOMe derivatives, including two deuterated derivatives (2C-B-d
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.JCHROMB.2017.04.008
Abstract: A novel microextraction technique based on ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction (UA-LDS-DLLME) had been applied for the determination of 4 designer benzodiazepines (phenazepam, diclazepam, flubromazepam and etizolam) in urine s les by gas chromatography- triple quadrupole mass spectrometry (GC-QQQ-MS). Ethyl acetate (168μL) was added into the urine s les after adjusting pH to 11.3. The s les were sonicated in an ultrasonic bath for 5.5min to form a cloudy suspension. After centrifugation at 10000rpm for 3min, the supernatant extractant was withdrawn and injected into the GC-QQQ-MS for analysis. Parameters affecting the extraction efficiency have been investigated and optimized by means of single factor experiment and response surface methodology (Box-Behnken design). Under the optimum extraction conditions, a recovery of 73.8-85.5% were obtained for all analytes. The analytical method was linear for all analytes in the range from 0.003 to 10μg/mL with the correlation coefficient ranging from 0.9978 to 0.9990. The LODs were estimated to be 1-3ng/mL. The accuracy (expressed as mean relative error MRE) was within ±5.8% and the precision (expressed as relative standard error RSD) was less than 5.9%. UA-LDS-DLLME technique has the advantages of shorter extraction time and is suitable for simultaneous pretreatment of s les in batches. The combination of UA-LDS-DLLME with GC-QQQ-MS offers an alternative analytical approach for the sensitive detection of these designer benzodiazepines in urine matrix for clinical and medico-legal purposes.
Publisher: Mary Ann Liebert Inc
Date: 05-2018
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 05-2014
DOI: 10.1016/J.FREERADBIOMED.2014.02.011
Abstract: The powerful oxidant HOCl (hypochlorous acid and its corresponding anion, (-)OCl) generated by the myeloperoxidase (MPO)-H2O2-Cl(-) system of activated leukocytes is strongly associated with multiple human inflammatory diseases consequently there is considerable interest in inhibition of this enzyme. Nitroxides are established antioxidants of low toxicity that can attenuate oxidation in animal models, with this ascribed to superoxide dismutase or radical-scavenging activities. We have shown (M.D. Rees et al., Biochem. J. 421, 79-86, 2009) that nitroxides, including 4-amino-TEMPO (4-amino-2,2,6,6-tetramethylpiperidin-1-yloxyl radical), are potent inhibitors of HOCl formation by isolated MPO and activated neutrophils, with IC50 values of ~1 and ~6 µM respectively. The utility of tetramethyl-substituted nitroxides is, however, limited by their rapid reduction by biological reductants. The corresponding tetraethyl-substituted nitroxides have, however, been reported to be less susceptible to reduction. In this study we show that the tetraethyl species were reduced less rapidly than the tetramethyl species by both human plasma (89-99% decreased rate of reduction) and activated human neutrophils (62-75% decreased rate). The tetraethyl-substituted nitroxides retained their ability to inhibit HOCl production by MPO and activated neutrophils with IC50 values in the low-micromolar range in some cases inhibition was enhanced compared to tetramethyl substitution. Nitroxides with rigid structures (fused oxaspiro rings) were, however, inactive. Overall, these data indicate that tetraethyl-substituted nitroxides are potent inhibitors of oxidant formation by MPO, with longer plasma and cellular half-lives compared to the tetramethyl species, potentially allowing lower doses to be employed.
Publisher: American Chemical Society (ACS)
Date: 03-10-1998
DOI: 10.1021/TX980118H
Publisher: Elsevier BV
Date: 12-1999
DOI: 10.1016/S0891-5849(99)00206-3
Abstract: The mechanisms of formation and the nature of the altered amino acid side chains formed on proteins subjected to oxidant attack are reviewed. The use of stable products of protein side chain oxidation as potential markers for assessing oxidative damage in vivo in humans is discussed. The methods developed in the authors laboratories are outlined, and the advantages and disadvantages of these techniques compared with other methodologies for assessing oxidative damage to proteins and other macromolecules. Evidence is presented to show that protein oxidation products are sensitive markers of oxidative damage, that the pattern of products detected may yield information as to the nature of the original oxidative insult, and that the levels of oxidized side-chains can, in certain circumstances, be much higher than those of other markers of oxidation such as lipid hydroperoxides.
Publisher: Elsevier BV
Date: 04-2002
DOI: 10.1016/S0891-5849(02)00768-2
Abstract: We demonstrate that oxidized amino acids can be incorporated into proteins by protein synthesis. The level of incorporation into protein was dependent on the concentration of oxidized amino acid supplied to the cells. At low levels of incorporation, the oxidized amino acids examined increased the degradation rate of the cell proteins. Degradation of certain proteins containing high levels of DOPA (but not ortho or meta tyrosine) was decreased to below the basal degradation rates suggesting that DOPA may contribute to proteins becoming resistant to proteolysis. Changes in the degradation rates of the oxidized amino acid-containing proteins was shown to have no impact on the degradation rates of native proteins, indicating that the activity of the degradative machinery was not affected. We demonstrate that oxidized proteins are selectively degraded by the proteasomes and provide evidence to suggest that the proteasomes and the endosomal-lysosomal systems may act in sequence as well as in parallel. The incorporation approach, unlike cell studies in which an exogenous oxidant is used, allows the degradation rates of the oxidatively modified proteins to be selectively measured, offering a greater sensitivity as well as greatly reducing toxicity to the cell and avoiding oxidative modification of other cell components.
Publisher: Wiley
Date: 07-10-2020
DOI: 10.1002/DTA.2926
Abstract: The surge in the consumption of food products containing herbal aphrodisiacs has driven their widespread adulteration. A rapid screening strategy is, therefore, warranted to curb this problem. This study established an enzyme inhibition assay to screen phosphodiesterase 5 (PDE5) inhibitors as adulterants in selected food products. Fluorescein-labelled cyclic-3',5'-guanosine monophosphate was utilised as substrates for the PDE5A1 enzyme, aided by the presence of nanoparticle phosphate-binding beads on their fluorescence polarisation. The s le preparation was optimised to improve the enzyme inhibition efficiency and applied to calculate the threshold values of six blank food matrices. The assay was validated using sildenafil, producing an IC
Publisher: Springer Science and Business Media LLC
Date: 10-07-2023
DOI: 10.1007/S00216-023-04822-4
Abstract: Accurate estimation of the postmortem interval (PMI) is crucial in forensic medico-legal investigations to understand case circumstances (e.g. narrowing down list of missing persons or include/exclude suspects). Due to the complex decomposition chemistry, estimation of PMI remains challenging and currently often relies on the subjective visual assessment of gross morphological/taphonomic changes of a body during decomposition or entomological data. The aim of the current study was to investigate the human decomposition process up to 3 months after death and propose novel time-dependent biomarkers (peptide ratios) for the estimation of decomposition time. An untargeted liquid chromatography tandem mass spectrometry–based bottom-up proteomics workflow (ion mobility separated) was utilized to analyse skeletal muscle, collected repeatedly from nine body donors decomposing in an open eucalypt woodland environment in Australia. Additionally, general analytical considerations for large-scale proteomics studies for PMI determination are raised and discussed. Multiple peptide ratios (human origin) were successfully proposed (subgroups 200 accumulated degree days (ADD), 655 ADD and 1535 ADD) as a first step towards generalised, objective biochemical estimation of decomposition time. Furthermore, peptide ratios for donor-specific intrinsic factors (sex and body mass) were found. Search of peptide data against a bacterial database did not yield any results most likely due to the low abundance of bacterial proteins within the collected human biopsy s les. For comprehensive time-dependent modelling, increased donor number would be necessary along with targeted confirmation of proposed peptides. Overall, the presented results provide valuable information that aid in the understanding and estimation of the human decomposition processes. Graphical Abstract
Publisher: Elsevier BV
Date: 04-2013
DOI: 10.1016/J.FORSCIINT.2012.11.006
Abstract: Oral fluid is currently used by Australian and international law enforcement agencies and employers to detect recent use of cannabis and other drugs of abuse. The main psychoactive constituent of cannabis, Δ(9)-tetrahydrocannabinol (THC), is highly lipophilic and losses occur when in contact with plastic, possibly due to its adsorption onto the plastic surface. This study aims to investigate factors governing the interaction of THC with plastic and search for ways of overcoming such interaction so to improve THC recovery. As polypropylene is one of the most common types of plastic used in collection devices, it was the focus of this study. All experiments were done by preparing neat oral fluid s les spiked with THC in 2-mL polypropylene centrifuge tubes. S les were transferred with or without prior addition of Triton(®) X-100 (0.25%) to glass tubes containing d3-THC as internal standard and 0.1M phosphate buffer was then added. S les were extracted by liquid-liquid extraction using hexane/ethyl acetate (9:1, v/v), dried and analysed by gas chromatography-mass spectrometry (GC-MS) after derivatisation. No significant difference was found in terms of THC loss to plastic when the concentration ranged from 25 to 1000 ng/mL in the same volume of oral fluid. Varying the oral fluid volume (0.5-1.5 mL) while keeping THC at a constant concentration showed an upward trend with more loss associated with lower volumes. The use of Triton(®) X-100 significantly decreased the adherence of THC to the plastic tubes and increased the THC transfer (>96%) at all volumes tested. Degradation of THC during storage was also studied over a 4-week period and it was found that azide did not seem to play a significant role in preserving THC in oral fluid.
Publisher: Future Science Ltd
Date: 09-2015
DOI: 10.4155/BIO.15.131
Abstract: Aim: Currently, procedures that identify the drugs ‘destroyed’ in adulterated urine specimens are very limited. This study aimed to determine the effect of pyridinium chlorochromate (PCC) on routine opiate assays and identify reaction products formed. Results/methodology: Opiate-positive urines adulterated with PCC (20 and 100 mM) were analyzed using CEDIA ® immunoassay and GC–MS. Urine and water s les spiked with 6-monoacetylmorphine, morphine and its glucuronides (10 µg/ml) and PCC (0.02–100 mM) were monitored with LC–MS, and the products characterized. Conclusion: PCC significantly decreased the abundance of morphine, codeine and IS. Adulterated water and urine s les containing 6-monoacetylmorphine, morphine and morphine-3-glucuronide yielded morphinone-3-glucuronide, 7,14-dihydroxy-6-monoacetylmorphine, 7,8-diketo-6-monoacetylmorphine and 7,8-diketo-morphine (tentative assignment). Reaction pathways may be different in the two matrices.
Publisher: Springer Science and Business Media LLC
Date: 13-10-2017
DOI: 10.1007/S00216-017-0681-3
Abstract: Neurotransmitters play crucial roles in physiological functions and their imbalances have demonstrated association in the pathology of several diseases. The measurement of neurotransmitters possesses a great potential as a significant clinical tool. This study presents the development and validation of an LC-MS/MS method for simultaneous quantification of multi-class neurotransmitters associated with dopamine, tryptophan and glutamate-γ-aminobutyric acid pathways. A total of ten neurotransmitters and their metabolites (dopamine, epinephrine, metanephrine, tryptophan, serotonin, kynurenic acid, kynurenine, anthranilic acid, GABA, glutamic acid) were determined based on a simple and rapid 'dilute and shoot' method using minimal urine volume. The chromatographic separation was achieved using a Poroshell 120 Bonus-RP LC Column in combination with a gradient elution within an 8.5-min time frame. The method exhibited good sensitivity as the limits of quantification ranged between 0.025 and 0.075 μg/mL with acceptable matrix effects (< ± 14.5%), no carryover and good linearity (r
Publisher: Wiley
Date: 17-04-2013
DOI: 10.1002/DTA.1476
Abstract: In vitro urine adulteration is a well-documented practice adopted by in iduals aiming to evade detection of drug use, when required to undergo mandatory sports and workplace drug testing. Potassium nitrite is an effective urine adulterant due to its oxidizing potential, and has been shown to mask the presence of many drugs of abuse. However, limited research has been conducted to understand its mechanism of action, and to explore the possibility of the drugs undergoing direct oxidation to form stable reaction products. In this study, opiates including morphine, codeine, morphine-3-glucuronide and morphine-6-glucuronide were exposed to potassium nitrite in water and urine to mimic the process of nitrite adulteration. It was found that two stable reaction products were detected by liquid chromatography-mass spectrometry (LC-MS) when morphine and morphine-6-glucuronide were exposed to nitrite. Isolation and elucidation using spectrometric and spectroscopic techniques revealed that they were 2-nitro-morphine and 2-nitro-morphine-6-glucuronide, respectively. These reaction products were also formed when an authentic morphine-positive urine specimen was fortified with nitrite. 2-Nitro-morphine was found to be stable enough to undergo the enzymatic hydrolysis procedure and also detectable by gas chromatography-mass spectrometry (GC-MS) after forming a trimethylsilyl derivative. On the contrary, morphine-3-glucuronide did not appear to be chemically manipulated when exposed to potassium nitrite in urine. These reaction products are not endogenously produced, are relatively stable and can be monitored with both LC-MS and GC-MS confirmatory techniques. As a result, these findings have revealed the possibility for the use of 2-nitro-morphine and 2-nitro-morphine-6-glucuronide as markers for the indirect monitoring of morphine and morphine-6-glucuronide in urine specimens adulterated with nitrite.
Publisher: Elsevier BV
Date: 07-2015
DOI: 10.1016/J.FREERADBIOMED.2015.03.029
Abstract: Hypochlorous acid (HOCl) and N-chloramines are produced by myeloperoxidase (MPO) as part of the immune response to destroy invading pathogens. However, MPO also plays a detrimental role in inflammatory pathologies, including atherosclerosis, as inappropriate production of oxidants, including HOCl and N-chloramines, causes damage to host tissue. Low molecular mass thiol compounds, including glutathione (GSH) and methionine (Met), have demonstrated efficacy in scavenging MPO-derived oxidants, which prevents oxidative damage in vitro and ex vivo. Selenium species typically have greater reactivity toward oxidants compared to the analogous sulfur compounds, and are known to be efficient scavengers of HOCl and other hypohalous acids produced by MPO. In this study, we examined the efficacy of a number of sulfur and selenium compounds to scavenge a range of biologically relevant N-chloramines and oxidants produced by both isolated MPO and activated neutrophils and characterized the resulting selenium-derived oxidation products in each case. A dose-dependent decrease in the concentration of each N-chloramine was observed on addition of the sulfur compounds (cysteine, methionine) and selenium compounds (selenomethionine, methylselenocysteine, 1,4-anhydro-4-seleno-L-talitol, 1,5-anhydro-5-selenogulitol) studied. In general, selenomethionine was the most reactive with N-chloramines (k2 0.8-3.4×10(3)M(-1) s(-1)) with 1,5-anhydro-5-selenogulitol and 1,4-anhydro-4-seleno-L-talitol (k2 1.1-6.8×10(2)M(-1) s(-1)) showing lower reactivity. This resulted in the formation of the respective selenoxides as the primary oxidation products. The selenium compounds demonstrated greater ability to remove protein N-chloramines compared to the analogous sulfur compounds. These reactions may have implications for preventing cellular damage in vivo, particularly under chronic inflammatory conditions.
Publisher: MDPI AG
Date: 30-12-2022
DOI: 10.3390/MOLECULES28010312
Abstract: The current approach to equine anti-doping is focused on the targeted detection of prohibited substances. However, as new substances are rapidly being developed, the need for complimentary methods for monitoring is crucial to ensure the integrity of the racing industry is upheld. Lipidomics is a growing field involved in the characterisation of lipids, their function and metabolism in a biological system. Different lipids have various biological effects throughout the equine system including platelet aggregation and inflammation. A certain class of lipids that are being reviewed are the eicosanoids (inflammatory markers). The use of eicosanoids as a complementary method for monitoring has become increasingly popular with various studies completed to highlight their potential. Studies including various corticosteroids, non-steroidal anti-inflammatories and cannabidiol have been reviewed to highlight the progress lipidomics has had in contributing to the equine anti-doping industry. This review has explored the techniques used to prepare and analyse s les for lipidomic investigations in addition to the statistical analysis and potential for lipidomics to be used for a longitudinal assessment in the equine anti-doping industry.
Publisher: Elsevier BV
Date: 05-2014
DOI: 10.1016/J.FORSCIINT.2014.03.004
Abstract: Sativex(®) is an oromucosal spray used to treat spasticity in multiple sclerosis sufferers in some European countries, the United Kingdom, Canada and New Zealand. The drug has also recently been registered by the Therapeutic Goods Administration (TGA) in Australia for treatment of multiple sclerosis. Sativex(®) contains high concentrations of Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD), with the former being the subject of random roadside drug tests across Australia to detect cannabis use. This pilot study aims to determine whether or not patients taking Sativex(®) will test positive to THC using these roadside screening tests. Detectable levels of THC, CBD and cannabinol (CBN) in their oral fluid were also confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The study was a double-blind, placebo controlled design. Oral fluid was tested prior to and immediately after dosing with either Sativex(®) or placebo at intervals up to 2h after the dose. Two Sativex(®) doses were studied. The low dose contained 5.4mg THC, the high dose 21.6mg THC. Results indicate that the primary screening test used in Australian roadside drug testing, the DrugWipe(®) II Twin, often gave a false negative response for THC, even with high concentrations present. However, secondary screening test, Cozart(®) DDS (used by police after a DrugWipe test gives a positive result), gave true positive results in all cases where patients were being treated with Sativex(®). Confirmatory testing showed high concentrations of THC and CBD (>5356ng/mL THC and >3826ng/mL CBD) in the oral fluid shortly after dosing and also elevated concentrations of CBN. Levels dropped quickly but remained at detectable concentrations (>67.6ng/mL) two hours after drug administration. The average concentration ratio of THC/CBD across all positive s les was 1.10 (%RSD 19.9) reflecting the composition of the Sativex(®) spray. In conclusion, Sativex(®) users may test positive for THC by roadside drug testing within 2-3h of use. Confirmatory analysis can identify Sativex(®) treatment through use of THC/CBD ratios, however, these ratios would unlikely be sufficient to differentiate non-medicinal cannabis use from Sativex(®) use if both are taken concurrently.
Publisher: Elsevier
Date: 2016
DOI: 10.1016/BS.ACC.2016.05.003
Abstract: Urine drug testing plays an important role in monitoring licit and illicit drug use for both medico-legal and clinical purposes. One of the major challenges of urine drug testing is adulteration, a practice involving manipulation of a urine specimen with chemical adulterants to produce a false negative test result. This problem is compounded by the number of easily obtained chemicals that can effectively adulterate a urine specimen. Common adulterants include some household chemicals such as hypochlorite bleach, laundry detergent, table salt, and toilet bowl cleaner and many commercial products such as UrinAid (glutaraldehyde), Stealth® (containing peroxidase and peroxide), Urine Luck (pyridinium chlorochromate, PCC), and Klear® (potassium nitrite) available through the Internet. These adulterants can invalidate a screening test result, a confirmatory test result, or both. To counteract urine adulteration, drug testing laboratories have developed a number of analytical methods to detect adulterants in a urine specimen. While these methods are useful in detecting urine adulteration when such activities are suspected, they do not reveal what types of drugs are being concealed. This is particularly the case when oxidizing urine adulterants are involved as these oxidants are capable of destroying drugs and their metabolites in urine, rendering the drug analytes undetectable by any testing technology. One promising approach to address this current limitation has been the use of unique oxidation products formed from reaction of drug analytes with oxidizing adulterants as markers for monitoring drug misuse and urine adulteration. This novel approach will ultimately improve the effectiveness of the current urine drug testing programs.
Publisher: Springer Science and Business Media LLC
Date: 02-08-2015
DOI: 10.1007/S00414-015-1241-Z
Abstract: Urinary 11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid (Carboxy-THC) concentrations, normalised to creatinine output, have been demonstrated to be a useful tool in the interpretation of the results of a series of urine tests for cannabis. These tests, often termed historical data, can be used to identify potential chronic cannabis users who may present occupational health and safety risks within the workplace. Conversely, the data can also be used to support employee claims of previous regular, rather than recent, cannabis use. This study aimed at examining the mean elimination of Carboxy-THC in 37 chronic users undergoing voluntary abstinence over a 2-week period. Urine specimens were collected prior to the study and after 1 and 2 weeks of abstinence. Carboxy-THC levels in urine were measured by gas chromatography-mass spectrometry (GC-MS) following alkaline hydrolysis, organic solvent extraction and derivatisation to form its pentafluoropropionic derivative. The creatinine-normalised Carboxy-THC concentrations declined rapidly over the 2 weeks of abstinence period and the majority of chronic cannabis users (73%) reduced their urinary Carboxy-THC levels to below the 15-μg/L confirmatory cutoff within that time. The study further highlights the value of historical urinary Carboxy-THC data as a means of identifying potential occupational health and safety risks among chronic cannabis users.
Publisher: Oxford University Press (OUP)
Date: 27-03-2020
Publisher: Wiley
Date: 03-06-2014
DOI: 10.1002/RCM.6935
Abstract: Pyridinium chlorochromate (PCC) is the active ingredient of 'Urine Luck', a commercially available in vitro adulterating agent used to conceal the presence of drugs in a urine specimen. The exposure of codeine and its major glucuronide metabolite codeine-6-glucuronide (C6G) to PCC was investigated to determine whether PCC is an effective masking agent for these opiate compounds. Following the addition of PCC to both spiked and authentic codeine and C6G-positive urine specimens, the s les were monitored using liquid chromatography/mass spectrometry (LC/MS). Stable reaction products were identified and characterized using high-resolution MS analysis and, where possible, nuclear magnetic resonance (NMR) analysis. It was determined that PCC effectively oxidizes codeine and C6G, thus altering the original codeine-to-C6G ratio in the urine specimen. Four reaction products were identified for codeine: codeinone, 14-hydroxycodeinone, 6-O-methylcodeine and 8-hydroxy-7,8-dihydrocodeinone. Similarly, three reaction products were identified for C6G: codeinone, codeine and a lactone of C6G (tentative assignment). Besides addressing the complications added to interpretation, more investigation is warranted to further determine their potential for use as markers for monitoring the presence of codeine and C6G in urine specimens adulterated with PCC.
Publisher: Oxford University Press (OUP)
Date: 05-02-2013
DOI: 10.1093/JAT/BKT003
Abstract: Pethidine (meperidine), a synthetic opiate, formally used as an analgesic in surgery and obstetrics, has been an abused drug of choice for some doctors. A case is presented in which a doctor, who previously admitted to using pethidine, was suspected of re-using, following a second positive urine test. A laboratory had reported the presence of pethidine in the doctor's urine however, the doctor denied re-use. The norpethidine (normeperidine) metabolite, normally found in urine, had not been detected, raising concern over the laboratory's conclusion and necessitating an independent investigation. Because the major metabolite of pethidine is pethidinic acid (meperidinic acid), accounting for approximately 40% of the excreted dose, its presence or absence were deemed to be important criteria in interpreting the laboratory result. Pethidinic acid was synthesized by alkaline hydrolysis of pethidine and used as a control. Urine s les from a patient receiving pethidine for pain, from the previous pethidine use of the doctor, and the urine under question plus the control were analyzed for the presence of pethidinic acid using electrospray mass spectrometry. Pethidinic acid was found in all s les except the one under dispute. The absence of pethidinic acid appeared to corroborate the doctor's denial of re-use.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 11-2012
Publisher: Elsevier BV
Date: 12-2011
DOI: 10.1016/J.DRUGALCDEP.2011.06.003
Abstract: Rates of treatment seeking for cannabis are increasing, and relapse is common. Management of cannabis withdrawal is an important intervention point. No psychometrically sound measure for cannabis withdrawal exists, and as a result treatment developments cannot be optimally targeted. The aim is to develop and test the psychometrics of the Cannabis Withdrawal Scale and use it to explore predictors of cannabis withdrawal. A volunteer s le of 49 dependent cannabis users provided daily scores on the Cannabis Withdrawal Scale during a baseline week and 2 weeks of abstinence. Internal reliability (Cronbach's alpha=0.91), test-retest stability (average intra-class correlation=0.95) and content validity analysis show that the Cannabis Withdrawal Scale has excellent psychometric properties. Nightmares and/or strange dreams was the most valid item (Wald χ²=105.6, P<0.0001), but caused relatively little associated distress (Wald χ²=25.11, P=0.03). Angry outbursts were considered intense (Wald χ²=73.69, P<0.0001) and caused much associated distress (Wald χ²=45.54, P<0.0001). Trouble getting to sleep was also an intense withdrawal symptom (Wald χ²=42.31, P<0.0001) and caused significant associated distress (Wald χ²=47.76, P<0.0001). Scores on the Severity of Dependence Scale predicted cannabis withdrawal. The Cannabis Withdrawal Scale can be used as a diagnostic instrument in clinical and research settings where regular monitoring of withdrawal symptoms is required.
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 04-2000
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3AY40511G
Publisher: Future Science Ltd
Date: 06-2014
DOI: 10.4155/BIO.14.102
Abstract: Drug testing programs are established to help achieve a drug-free work environment, promote fair competition in sport, facilitate harm minimization and rehabilitation programs, better manage patient care by clinicians and service law enforcement authorities. Urine remains the most popular and appropriate testing matrix for such purposes. However, urine is prone to adulteration, where chemicals, especially oxidizing chemicals, are purposely added to the collected urine specimens to produce a false-negative test result. This article will describe the effect of various popular oxidizing adulterants on urine drug test results, the countermeasures taken by laboratories in dealing with adulterated urine s les and the prospect of developing more robust and economical methods to combat urine adulteration in the future.
Publisher: Springer New York
Date: 2018
DOI: 10.1007/978-1-4939-8579-1_1
Abstract: Color tests are a key tool for the rapid and simple identification of seized illicit drugs. This chapter outlines a series of color tests that can be used for the preliminary identification of new psychoactive substances such as cathinones, piperazines, tryptamines, and hetamine-type stimulants.
Publisher: Informa UK Limited
Date: 07-08-2019
Publisher: Elsevier BV
Date: 2013
DOI: 10.1016/J.FORSCIINT.2012.10.040
Abstract: Amphetamine-type substances (ATS), like other synthetically derived compounds, can be produced by a multitude of synthetic pathways using a variety of precursors and reagents, resulting in a large number of possible contaminants (by-products, intermediates and impurities). This review article describes the common contaminants found in preparations of methyl hetamine (MA), 3,4-methylenedioxymethyl hetamine (MDMA), hetamine (AP), N,N-dimethyl hetamine (DMA) and p-methoxy hetamine (PMA) synthesised via common synthetic pathways including reductive amination, Leuckart method, Nagai method, Emde method, Birch reduction, "Moscow" method, Wacker process, "Nitrostyrene" method and the Peracid oxidation method. Contaminants can facilitate identification of the synthetic route, origin of precursors and may suggest information as to the location of manufacture of these illicit drugs. Contaminant profiling can provide vital intelligence for investigations in which linking seizures or identifying the synthetic pathway is essential. This review article presents an accessible resource a compilation of contaminants resulting from a variety of manufacturing methods used to synthesise the most common ATS. It is important for research in this field to continue as valuable information can be extracted from illicit drug s les, increasing discrimination amongst ATS, and in turn, leading to an increase in evidential value and forensic drug intelligence from forensic drug s les.
Publisher: Springer Science and Business Media LLC
Date: 28-04-2017
DOI: 10.1208/S12248-017-0078-4
Abstract: The knowledge of metabolic profile of synthetic cannabinoids is important for the detection of drugs in urinalysis due to the typical absence or low abundance of parent cannabinoids in human urine. The fungus Cunninghamella elegans has been reported to be a useful tool for metabolism study and thus applicability to synthetic cannabinoid metabolism was examined. In this study, 8-quinolinyl 1-(5-fluoropentyl)-1H-indole-3-carboxylate (5F-PB-22), 8-quinolinyl 1-pentyl-1H-indole-3-carboxylate (PB-22), [1-(5-fluoropentyl)-1H-indol-3-yl](2,2,3,3-tetramethylcyclopropyl)methanone (XLR-11) and (1-pentyl-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone (UR-144) were incubated with C. elegans and the metabolites were identified using liquid chromatography-quadrupole time-of-flight mass spectrometry. The obtained metabolites were compared with reported human metabolites to assess the suitability of the fungus to extrapolate human metabolism. 5F-PB-22 underwent dihydroxylation, dihydrodiol formation, oxidative defluorination, oxidative defluorination to carboxylic acid, ester hydrolysis and glucosidation, alone and/or in combination. The metabolites of PB-22 were generated by hydroxylation, dihydroxylation, trihydroxylation, dihydrodiol formation, ketone formation, carboxylation, ester hydrolysis and glucosidation, alone and/or in combination. XLR-11 was transformed through hydroxylation, dihydroxylation, aldehyde formation, carboxylation, oxidative defluorination, oxidative defluorination to carboxylic acid and glucosidation, alone and/or in combination. UR-144 was metabolised by hydroxylation, dihydroxylation, trihydroxylation, aldehyde formation, ketone formation, carboxylation, N-dealkylation and combinations. These findings were consistent with previously reported human metabolism except for the small extent of ester hydrolysis observed and the absence of glucuronidation. Despite the limitations, C. elegans demonstrated the capacity to produce a wide variety of metabolites including some major human metabolites of XLR-11 and UR-144 at high abundance, showing the potential for metabolism of newly emerging synthetic cannabinoids.
Publisher: Oxford University Press (OUP)
Date: 1999
DOI: 10.1086/314552
Abstract: To investigate the involvement of oxidative tissue damage in the pathogenesis of murine cerebral malaria (CM), brain levels of protein carbonyls, 3,4-dihydroxyphenylalanine (DOPA), o-tyrosine, and dityrosine were measured during Plasmodium berghei ANKA (PbA) and P. berghei K173 (PbK) infections. During PbA infection in a CM model, brain levels of the substances were similar to those in uninfected mice. The role of phagocyte-derived reactive oxygen species in the pathogenesis of CM was examined in gp91phox gene knockout mice. The course of CM in these mice was the same as in their wild type counterparts. To examine whether superoxide production in the central nervous system could have occurred via increased xanthine oxidase activity, brain concentrations of urate were measured in CM mice and in mice infected with PbK (which does not cause CM). Brain urate concentration increased significantly in both groups of mice, suggesting that purine breakdown is not specific to CM. These results indicate that reactive oxygen species probably do not contribute to the pathogenesis of murine CM.
Publisher: Oxford University Press (OUP)
Date: 31-12-2014
DOI: 10.1093/JAT/BKU144
Abstract: An analytical method was developed and validated for the purpose of detecting and quantifying 37 new designer drugs including cathinones, hallucinogenic phenethylamines and piperazines. Using only 100 µL whole blood, a salting-out-assisted liquid-liquid extraction with acetonitrile was performed to isolate target compounds followed by chromatographic separation using a Waters ACQUITY ultra performance liquid chromatograph coupled to a Waters XEVO quadrupole time-of-flight mass spectrometer. Mephedrone-d3 was used as an internal standard. A gradient elution was used in combination with a Waters ACQUITY HSS C18 column (2.1 × 150 mm, 1.8 µm). S les were analyzed using the detector in positive electrospray ionization mode with MS(E) acquisition. All compounds of interest were resolved in a 15 min run time and positively identified based on accurate mass of the molecular ion, two product ions and retention time. All analyte calibration curves were linear over the range of 0.05-2 mg/L with most correlation coefficient (r(2)) values >0.98. The limits of detection were within the range of 0.007-0.07 mg/L and limits of quantification within 0.05-0.1 mg/L. All analytes were stable 48 h after extraction and most were stable in blood after 1 week stored in a refrigerator and 3 freeze-thaw cycles. No carryover was observed up to 10 mg/L and no interferences from common therapeutic drugs or endogenous compounds. Recoveries ranged from 71 to 100% and matrix effects were assessed for blank, post-mortem and decomposed blood. All bias and % coefficient of variation values were within the acceptable values of ±15 and ≤15%, respectively (±20 and ≤20% at lower limit of quantification). The method was applied to several forensic cases where the subject exhibited behavior characteristic of designer drug intoxication and where routine screening for a panel of drugs was negative.
Publisher: Wiley
Date: 2021
DOI: 10.1002/CTI2.1318
Abstract: The high morbidity and mortality of neuroinflammatory diseases drives significant interest in understanding the underlying mechanisms involved in the innate and adaptive immune response of the central nervous system (CNS). Diagnostic biomarkers are important to define treatable neuroinflammation. Metabolomics is a rapidly evolving research area offering novel insights into metabolic pathways, and elucidation of reliable metabolites as biomarkers for diseases. This review focuses on the emerging literature regarding the detection of neuroinflammation using cerebrospinal fluid (CSF) metabolomics in human cohort studies. Studies of classic neuroinflammatory disorders such as encephalitis, CNS infection and multiple sclerosis confirm the utility of CSF metabolomics. Additionally, studies in neurodegeneration and neuropsychiatry support the emerging potential of CSF metabolomics to detect neuroinflammation in common CNS diseases such as Alzheimer's disease and depression. We demonstrate metabolites in the tryptophan–kynurenine pathway, nitric oxide pathway, neopterin and major lipid species show moderately consistent ability to differentiate patients with neuroinflammation from controls. Integration of CSF metabolomics into clinical practice is warranted to improve recognition and treatment of neuroinflammation.
Publisher: Public Library of Science (PLoS)
Date: 26-09-2012
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.STEROIDS.2012.12.001
Abstract: Steroid profiling is the most versatile and informative technique adapted by doping control laboratories for detection of steroid abuse. The absolute concentrations and ratios of endogenous steroids including testosterone, epitestosterone, androsterone, etiocholanolone, 5α-androstane-3α,17β-diol and 5β-androstane-3α,17β-diol constitute the significant characteristics of a steroid profile. In the present study we report the influence of various oxidizing adulterants on the steroid profile of human urine. Gas chromatography-mass spectrometry analysis was carried out to develop the steroid profile of human male and female urine. Oxidants potassium nitrite, sodium hypochlorite, potassium permanganate, cerium ammonium nitrate, sodium metaperiodate, pyridinium chlorochromate, potassium dichromate and potassium perchlorate were reacted with urine at various concentrations and conditions and the effect of these oxidants on the steroid profile were analyzed. Most of the oxidizing chemicals led to significant changes in endogenous steroid profile parameters which were considered stable under normal conditions. These oxidizing chemicals can cause serious problems regarding the interpretation of steroid profiles and have the potential to act as masking agents that can complicate or prevent the detection of the steroid abuse.
Publisher: Elsevier BV
Date: 06-2016
Publisher: Springer Science and Business Media LLC
Date: 24-05-2018
Publisher: Elsevier BV
Date: 08-2016
Publisher: Springer Science and Business Media LLC
Date: 06-02-2011
DOI: 10.1007/S00216-011-4723-Y
Abstract: It has been previously reported that treatment of urinary oxazepam by commercial β-glucuronidase enzyme preparations, from Escherichia coli, Helix pomatia and Patella vulgata, results in production of nordiazepam (desmethyldiazepam) artefact. In this study, we report that this unusual reductive transformation also occurs in other benzodiazepines with a hydroxyl group at the C3 position such as temazepam and lorazepam. As determined by liquid chromatography-mass spectrometry analysis, all three enzyme preparations were found capable of converting urinary temazepam into diazepam following enzymatic incubation and subsequent liquid-liquid extraction procedures. For ex le, when H. pomatia enzymes were used with incubation conditions of 18 h and 50 °C, the percentage conversion, although small, was significant--approximately 1% (0.59-1.54%) in both patient and spiked blank urines. Similarly, using H. pomatia enzyme under these incubation conditions, a reductive transformation of urinary lorazepam into delorazepam (chlordesmethyldiazepam) occurred. These findings have both clinical and forensic implications. Detection of diazepam or delorazepam in biological s les following enzyme treatment should be interpreted with care.
Publisher: Elsevier BV
Date: 07-1993
Publisher: Springer Science and Business Media LLC
Date: 03-2018
DOI: 10.1208/S12248-018-0209-6
Abstract: The number of new psychoactive substances keeps on rising despite the controlling efforts by law enforcement. Although metabolism of the newly emerging drugs is continuously studied to keep up with the new additions, the exact structures of the metabolites are often not identified due to the insufficient s le quantities for techniques such as nuclear magnetic resonance (NMR) spectroscopy. The aim of the study was to characterise several metabolites of the synthetic cannabinoid (1-pentyl-1H-indol-3-yl) (2,2,3,3-tetramethylcyclopropyl) methanone (UR-144) by NMR spectroscopy after the incubation with the fungus Cunninghamella elegans. UR-144 was incubated with C. elegans for 72 h, and the resulting metabolites were chromatographically separated. Six fractions were collected and analysed by NMR spectroscopy. UR-144 was also incubated with human liver microsomes (HLM), and the liquid chromatography-high resolution mass spectrometry analysis was performed on the HLM metabolites with the characterised fungal metabolites as reference standards. Ten metabolites were characterised by NMR analysis including dihydroxy metabolites, carboxy and hydroxy metabolites, a hydroxy and ketone metabolite, and a carboxy and ketone metabolite. Of these metabolites, dihydroxy metabolite, carboxy and hydroxy metabolites, and a hydroxy and ketone metabolite were identified in HLM incubation. The results indicate that the fungus is capable of producing human-relevant metabolites including the exact isomers. The capacity of the fungus C. elegans to allow for NMR structural characterisation by enabling production of large amounts of metabolites makes it an ideal model to complement metabolism studies.
Publisher: Elsevier BV
Date: 09-1995
DOI: 10.1016/0891-5849(95)00021-O
Abstract: We have previously demonstrated the formation of two reactive moieties on proteins during free radical attack: hydroperoxides, and 3,4-dihydroxyphenylalanine (DOPA). Here we have undertaken the structural elucidation of the hydroperoxides of valine, the amino acid which is most susceptible to peroxidation. Exposure of L-valine to free radicals generated by radiolysis in an oxygen-saturated system produced three valine hydroperoxides. Upon treatment with sodium borohydride these were reduced to their corresponding hydroxides, which can be separated and purified by high performance liquid chromatography (HPLC). Based on spectroscopic data from high resolution chemical ionization (CI) mass spectrometry (MS), electrospray (ES) MS, electron impact (EI) MS, proton (1H) nuclear magnetic resonance (NMR) and carbon-13 (13C) NMR studies, the three valine hydroxides have been identified as beta-hydroxyvaline [(2S)-2-amino-3-hydroxy-3-methyl-butanoic acid], (2S,3S)-gamma-hydroxyvaline [(2S,3S)-2-amino-3-hydroxymethyl-butanoic acid], and (2S,3R)-gamma-hydroxyvaline [(2S,3R)-2-amino-3-hydroxymethyl-butanoic acid]. HPLC analysis of O-phthaldialdehyde (OPA) derivatives of the hydroxyvalines provides a sensitive and accurate method for quantitative measurement. This method enabled hydroxyvalines to be detected in the hydrolysates of a tripeptide (glutamyl-valinyl-phenylalanine) and a protein (bovine serum albumin) that had been gamma-radiolysed and treated with sodium borohydride. Hydroxyvaline may be useful as a marker in studying protein oxidation in some biological systems under oxidative stress.
Publisher: Wiley
Date: 08-03-2022
DOI: 10.1002/DTA.3245
Abstract: Metabolomics is a multidisciplinary field providing workflows for complementary approaches to conventional analytical determinations. It allows for the study of metabolically related groups of compounds or even the study of novel pathways within the biological system. The procedural stages of metabolomics experimental design, s le preparation, analytical determinations, data processing and statistical analysis, compound identification and validation strategies are explored in this review. The selected approach will depend on the type of study being conducted. Experimental design influences the whole metabolomics workflow and thus needs to be properly assessed to ensure sufficient s le size, minimal introduced and biological variation and appropriate statistical power. S le preparation needs to be simple, yet potentially global in order to detect as many compounds as possible. Analytical determinations need to be optimised either for the list of targeted compounds or a universal approach. Data processing and statistical analysis approaches vary widely and need to be better harmonised for review and interpretation. This includes validation strategies that are currently deficient in many presented workflows. Common compound identification approaches have been explored in this review. Metabolomics applications are discussed for clinical and forensic toxicology, human and equine sports anti-doping and veterinary residues.
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.FORSCIINT.2016.01.006
Abstract: There is currently limited data available on the stabilities of the three stimulants 4-methylmethcathinone (4-MMC), 3,4-methylenedioxymeth hetamine (MDMA) and N-benzylpiperazine (BZP) in a putrefying matrix. A Gas Chromatography Mass Spectrometry (GC-MS) method to determine the concentration of the three drugs in putrefying porcine liver over a three month period was developed and validated. Both 4-MMC and BZP were found to be unstable, becoming undetectable and having an average recovery of 52% respectively after one month at ambient room temperature (20°C). MDMA was found to be moderately stable, with an average recovery of 74% after three months at room temperature. This study indicated that the putrefaction process could have a significant impact on concentrations of 4-MMC and BZP in post-mortem cases involving putrefied remains.
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 2010
Publisher: Elsevier BV
Date: 03-1996
DOI: 10.1016/0031-9422(95)00734-2
Abstract: Three trypsin inhibitors from Sicyos australis, have been isolated, purified and sequenced. Following protein extraction with ammonium sulphate, the mixture of inhibitors was separated from other proteins by trypsin-affinity chromatography. Subsequent purification of the in idual inhibitors was accomplished by reversed-phase HPLC. The primary structures of each inhibitor were elucidated by a combination of protein sequencing and electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS-MS) on both the untreated and the reduced and S-carboxymethylated inhibitors. All three inhibitors show extensive sequence similarity with inhibitors from cultivated Cucurbitaceae species, although there are a number of novel residues present. One of the inhibitors has a blocked N-terminus (pyroglutamic acid) and the use of MS-MS was crucial to the elucidation of its primary structure. ESI-MS was further used to characterize the non-covalent complex between one of the inhibitors and trypsin.
Publisher: Wiley
Date: 04-03-2022
DOI: 10.1002/DTA.3244
Abstract: The conventional detection of exogenous drugs in equine doping s les has been used for confirmation and subsequent prosecution of participants responsible. In recent years, alternative methods using indirect detection have been investigated due to the expanding number of pharmaceutical agents available with the potential of misuse. The monitoring of endogenous biomarkers such as hydrocortisone (HC) has been studied in equine urine with an international threshold of 1 μg/ml established however, there is no current threshold for equine plasma. The aim of this research was to investigate plasma concentrations of HC and cortisone (C) in race day s les compared to an administration of Triamcinolone Acetonide (TACA). The reference population ( n = 1150) provided HC (6 to 145 ng/ml) and C (0.7 to 13 ng/ml) levels to derive the HC to C ratio (HC/C). Population reference limits (PRLs) were proposed for HC/C values at 0.2 (lower) and 61 (upper). Administration of TACA resulted in down‐regulation of HC/C values below the estimated PRLs for up to 96 h post‐administration. This indirect detection period was longer than the detection of TACA for 72 h. The use of in idual reference limits (IRLs) for HC/C values was investigated to support the Equine Biological Passport (EBP), an intelligence model developed by Racing NSW for longitudinal monitoring of biomarkers.
Publisher: Springer Science and Business Media LLC
Date: 14-02-2022
DOI: 10.1007/S11419-022-00612-2
Abstract: JWH-424, (8-bromo-1-naphthyl)(1-pentyl-1H-indol-3-yl)methanone, is a synthetic cannabinoid, which is a brominated analogue of JWH-018, one of the best-known synthetic cannabinoids. Despite the structural similarity to JWH-018, little is known about JWH-424 including its metabolism. The aim of the study was to compare human liver microsomes (HLM) and the fungus Cunninghamella elegans as the metabolism catalysts for JWH-424 to better understand the characteristic actions of the fungus in the synthetic cannabinoid metabolism. JWH-424 was incubated with HLM for 1 h and Cunninghamella elegans for up to 72 h. The HLM incubation mixtures were diluted with methanol and fungal incubation mixtures were extracted with dichloromethane and reconstituted in methanol before analyses by liquid chromatography-high-resolution mass spectrometry (LC-HRMS). HLM incubation resulted in production of ten metabolites through dihydrodiol formation, hydroxylation, and/or ipso substitution of the bromine with a hydroxy group. Fungal incubation led to production of 23 metabolites through carboxylation, dihydrodiol formation, hydroxylation, ketone formation, glucosidation and/or sulfation. Generally, HLM models give good predictions of human metabolites and structural analogues are metabolised in a similar fashion. However, major hydroxy metabolites produced by HLM were those hydroxylated at naphthalene instead of pentyl moiety, the major site of hydroxylation for JWH-018. Fungal metabolites, on the other hand, had undergone hydroxylation mainly at pentyl moiety. The metabolic disagreement suggests the necessity to verify the human metabolites in authentic urine s les, while H9 and H10 (hydroxynaphthalene), H8 (ipso substitution), F22 (hydroxypentyl), and F17 (dihydroxypentyl) are recommended for monitoring of JWH-424 in urinalysis.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3AY40181B
Publisher: Elsevier BV
Date: 08-2019
Publisher: Future Science Ltd
Date: 04-2016
Abstract: Sativex ® is an oromucosal spray indicated for the treatment of moderate-to-severe spasticity in multiple sclerosis and is also an effective analgesic for advanced cancer patients. Sativex contains Δ 9 -tetrahydrocannabinol (THC) and cannabidiol in an approximately 1:1 ratio. The increasing prevalence of medicinal cannabis products highlights the importance of reliable bioanalysis and re-evaluation of the interpretation of positive test results for THC, as legal implications may arise in workplace, roadside and sports drug testing situations. This article summarizes published research on the bioanalysis of THC and cannabidiol, with particular focus on Sativex. Common screening and confirmatory testing of blood, urine, oral fluid and hair s les are outlined. Correlations between matrices and current analytical pitfalls are also addressed.
Publisher: Frontiers Media SA
Date: 14-05-2019
Publisher: Wiley
Date: 19-08-2021
DOI: 10.1002/DTA.2905
Abstract: The great increase of new psychoactive substances over the past decade has substantially transformed the illicit drug industry to an ever-changing dynamic market. 25-NBOMe compounds are just one of these new substance groups that pose a public health risk in many countries around the world. These highly potent, hallucinogenic phenethylamines have previously been sold as "legal highs" or "synthetic LSD" and the necessity to rapidly identify their presence is crucial. While there are many laboratory-based analytical methods capable of identifying these compounds, the lack of presumptive test methods indicates the need for a specific and timely test that could be used in the field. Herein we outline the developed chemical spot test that can selectively identify the presence of 25-NBOMe compounds and related analogs through the reaction with a substituted benzoquinone reagent under basic conditions. This test method has been comprehensively validated showing a high level of selectivity, specificity, and precision with only two other illicit substances producing similar positive results as 25-NBOMe and few false-negative results seen. The working limit of detection was determined to be 225 μg and there was no cross-reactivity from potential adulterants of significance. This test has also been shown to work directly with blotter papers containing 25-NBOMe compounds, indicating no interference from this common matrix and the ability to differentiate these compounds from LSD. This method shows a high potential to be translated to a field compatible test that is simple, rapid, and selective for 25-NBOMe compounds.
Publisher: Elsevier BV
Date: 12-1999
DOI: 10.1016/S1357-2725(99)00107-7
Abstract: Oxidation of low density lipoprotein (LDL) may be atherogenic, but radical-initiated oxidation of its apoprotein B-100 (apoB) has been little studied. Transition metal ions iron and copper are candidates for mediating radical oxidation of LDL in vivo. Therefore, we studied the copper-ion-induced oxidation of apoB in human LDL. Using HPLC methods developed in our recent work, we studied the destruction of native and the generation of six oxidised amino acids we also assessed the release of peptides from the LDL particle by FPLC. We observed time-dependent losses of apoB histidine, lysine and glycine. Long-lived reactive species, the reductant DOPA, and the oxidant hydroperoxides of valine and leucine (measured as hydroxides after reduction), were generated. Their relative abundance (mol/mol of parent amino acid) was DOPA > o- and m-tyrosine > dityrosine, valine-hydroxides, leucine hydroxides. Low molecular weight fragments were also released from the LDL in a time-dependent manner, contained hydroperoxides sensitive to GSH peroxidase, and generated radicals on reaction with iron-EDTA. The fragments contained peptides active in the quinone redox cycling procedure, comprising 0.25% of the supplied LDL amino acids. Characteristic peptides were present in each FPLC fraction containing the fragments, as judged by further HPLC fractionation. Some fragments were present in the unoxidised LDL preparations, and when these were largely removed by FPLC, copper oxidation could still generate fragments, suggesting that those present in the starting material might indicate prior oxidation. Concordantly, we found that fresh plasma LDL apoB contained 43% of total plasma protein-bound oxidised amino acids, and with the same relative abundance. We conclude that plasma proteins including apoB are subject to physiological oxidation, similar to that inflicted by copper ions the latter may contribute to intimal LDL oxidation, which could be the source of oxidised plasma apoB.
Publisher: Elsevier BV
Date: 10-1997
Publisher: American Chemical Society (ACS)
Date: 03-1989
DOI: 10.1021/NP50062A046
Publisher: Springer Science and Business Media LLC
Date: 19-12-2016
DOI: 10.1007/S00414-016-1518-X
Abstract: Poisoning by organophosphorus insecticides such as methamidophos makes up a significant portion of forensic identification cases in China. Stability of methamidophos during specimen storage remains largely unknown. This study aimed to examine the long-term stability of methamidophos in postmortem specimens. Three experimental dogs after oral administration of methamidophos were sacrificed, and blood and liver specimens were collected and stored at various conditions. Gas chromatography-mass spectrometry (GC/MS) was used to measure the methamidophos concentrations after 0, 4, 7, 12, 16, 60, and 180 days of storage. The results showed that methamidophos was not stable and followed first-order degradation kinetics at all storage conditions investigated. The degradation half-life in blood was 12.2, 16.9, 11.0, and 1.0 days when the s les were stored at room temperature (RT, 20 °C), 4 °C, -20 °C, and at RT with 1 % sodium fluoride (NaF), respectively. The degradation half-life in liver was 4.1, 9.8, 17.8, and 2.0 days when the s les were stored at RT, 4 °C, -20 °C, and at RT with liver fixed in 10 % formaldehyde solution, respectively. These findings are significant in guiding s le storage and data interpretation. Specimens containing methamidophos should be stored at -20 °C and analyzed as early as possible. Addition of NaF in blood and fixation of liver in formaldehyde should be avoided due to the accelerated degradation of methamidophos under these conditions. The preliminary study suggests that it might be possible to calculate methamidophos concentration at the time of death based on its first-order degradation kinetic under specific storage conditions.
Start Date: 07-2015
End Date: 12-2015
Amount: $430,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2018
End Date: 12-2019
Amount: $435,279.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2017
End Date: 12-2023
Amount: $3,708,510.00
Funder: Australian Research Council
View Funded Activity