ORCID Profile
0000-0003-1383-6299
Current Organisation
Universidade Federal de Minas Gerais
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Publisher: Sociedade Brasileira de Quimica (SBQ)
Date: 2019
Publisher: AIP Publishing
Date: 08-2023
DOI: 10.1063/5.0169672
Publisher: Elsevier BV
Date: 15-12-2005
DOI: 10.1016/J.JCHROMB.2005.09.030
Abstract: A headspace solid phase microextraction (SPME) method has been developed to determine metabolites of dimethylformamide, N-hydroxymethyl-N-methylformamide, and N-methylformamide (NMF) as NMF in urine by gas chromatography with nitrogen-phosphorus detector (GC-NPD). An SPME holder with a 65-microm PDMS/DVB fiber coating was used. Optimal desorption conditions were 250 degrees C for 1 min, adsorption at 80 degrees C for 15 min, and 3.00 mL of s le in the headspace vial. The method presented good resolution, repeatability, recovery, detection limit, ruggedness and response linearity.
Publisher: Informa UK Limited
Date: 07-2013
DOI: 10.1080/19440049.2013.801088
Abstract: Coffee is a major tropical agricultural commodity and represents a significant fraction of the economy of many countries. However, certain plant and animal species can damage coffee crops, affecting trade. A solution to this issue is the use of pesticides, some of which are harmful to human health and the environment. This work consisted of the development of a multi-residue method for the analysis of pesticides in coffee by using LC-MS/MS. The QuEChERS extraction procedure was used. The following analytical parameters were optimised: selectivity, analytical range, linearity, LOD, LOQ, precision (RSD%) and recovery of the method. The results showed that the method is selective, as they were linear in the range of 10.0-100.0 µg kg(-1). The sensitivity, recovery and precision were adequate for the multi-residue analysis of pesticides in coffee. The method was applied to the analyses of 15 Brazilian coffee s les.
Publisher: Springer Science and Business Media LLC
Date: 15-02-2017
DOI: 10.1007/S00216-017-0226-9
Abstract: Acrolein is a pollutant released daily to the indoor environment from different sources. The present study reports the development of a simple and sensitive cold fiber solid phase microextraction s ling method for the determination of acrolein in exhaled air and indoor air by gas chromatography mass spectrometry. O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine was used as derivatizing agent supported on a 65-μm polydimethylsiloxane- inylbenzene SPME fiber. An acrolein permeation tube at 326.25 ng min
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.CHROMA.2016.12.043
Abstract: Phthalates and bisphenol A are important environmental pollutants due to their toxicity for humans and animals, including actions in the endocrine system. Their metabolites in urine can be used as biomarkers to assess human exposure. This paper describes the development of a new method to determine bisphenol A and eight phthalate metabolites in urine s les using hollow fiber liquid phase microextraction (HF-LPME) and gas chromatography-mass spectrometry (GC-MS). This method showed linearity, precision, limits of detection, and quantification suitable to analyze these compounds at low concentration levels in urine. Limits of detection ranged from 0.777 to 23.3μgL
Publisher: Oxford University Press (OUP)
Date: 07-1993
DOI: 10.1093/JAT/17.4.193
Abstract: The calibration method described is based on the in situ formation of carbon monoxide in a closed system by the reaction of hot concentrated sulfuric acid with formic acid. Carbon monoxide is released from hemoglobin by treatment with 85% phosphoric acid, diluted 1:2 (v/v). Carbon monoxide is analyzed by means of headspace gas chromatography on a Porapak Q 80-100 column, following catalytic reduction to methane, using a flame-ionization detector. The method was validated by comparing the results obtained for blood s les from patients suffering from carbon monoxide poisoning and previously analyzed by means of spectrophotometry.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4NR04005H
Abstract: Due to the combination of hydrophobic/hydrophilic sections coupled with encapsulated catalyst particles, N-doped CNTs behave like magnetic tensioactive agents.
Publisher: Wiley
Date: 20-01-2021
DOI: 10.1002/AUR.2475
Publisher: FapUNIFESP (SciELO)
Date: 21-07-2016
Publisher: Elsevier BV
Date: 02-2009
Publisher: Elsevier BV
Date: 05-2020
Publisher: MDPI AG
Date: 30-12-2013
Publisher: Elsevier BV
Date: 09-2020
Publisher: FapUNIFESP (SciELO)
Date: 12-2001
Publisher: Elsevier BV
Date: 07-2020
Publisher: Sociedade Brasileira de Quimica (SBQ)
Date: 2023
DOI: 10.21577/0103-5053.20230005
Abstract: Metabolomics can provide a readout of the biochemical and physiological state of a biological system. Gas chromatography coupled to mass spectrometry (GC-MS) has been widely applied for metabolomic analysis due to its numerous advantages, such as good sensitivity, high resolution, reproducibility, extensive database, lower acquisition cost and greater coverage. In addition, combined with efficient methods of s ling and s le preparation, the metabolomic analysis of damaged skin based on GC-MS can provide an important step toward elucidating several skin diseases. Based on this, this review presents a comprehensive overview of s ling, s le preparation, data processing and GC-MS analysis of metabolomic studies of damaged skin. Also, part of the biological interpretation of metabolites such as cis- and trans-urocanic acid (UCA) altered in photoexposed skin and lauric acid (C12:0) and palmitic acid (C16:0) in melanoma is discussed. Finally, to improve decision-making, a part of the integration of skin metabolomics with other omics sciences for the advancement of diagnosis is presented.
Publisher: Magnolia Press
Date: 09-01-2018
DOI: 10.11646/PHYTOTAXA.333.2.2
Abstract: During a bioprospecting of fungi producing antimicrobial volatile organic compounds, two Verticillium-like isolates from coffee branches were obtained by a parallel growth technique using Muscodor albus CZ 620. Micro-morphological characteristics and phylogenetic analyses showed that both isolates belonged to Simplicillium and represented a new species, namely S. coffeanum. In the test for antimicrobial activity, the mixture of volatiles emitted by S. coffeanum COAD 2057 inhibited the growth of Aspergillus ochraceus, A. tubingensis, A. sydowii and A. niger on PDA. Among the compounds of volatile mixture, 1-Propanone, 1-(5-methyl-2-furanyl)-, Cyclopropane, 1-ethoxy-2, 2-dimethyl-3-(2-phenylethynyl)-, and 2-Propenoic acid, 3-(2-formyl-4-methoxyphenyl)-, ethyl ester, (E)- possessed the highest percentage of peak per area. Therefore, S. coffeanum has potentially biocontrol ability through the emission of antimicrobial volatiles.
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.ACA.2018.12.017
Abstract: The extensive use of pesticides promotes environmental contamination, mainly in surface and ground waters. However, they remain at very low concentration and present wide degradation level requiring the use of efficient devices for pesticides passive s ling. In this study, a new in situ passive s ling device was developed for monitoring and estimating time-weighted average (TWA) of pesticides in waters. The device was made with simple, recyclable and cheap materials. The s ling system involves the liquid phase microextraction technique with hollow fiber in two-phases mode. Pesticides determination was done by gas chromatography coupled to mass spectrometry. The method was optimized and validated for the determination of 29 pesticides in water, showing good linearity in the range between 0.012 and 40.00 μg L
Publisher: Elsevier BV
Date: 15-07-1992
Publisher: FapUNIFESP (SciELO)
Date: 2009
Publisher: FapUNIFESP (SciELO)
Date: 04-1999
Publisher: GN1 Genesis Network
Date: 2013
DOI: 10.4322/SC.2014.012
Publisher: Elsevier BV
Date: 11-2019
Publisher: Springer Science and Business Media LLC
Date: 05-2001
DOI: 10.1007/BF02491617
Publisher: Springer Science and Business Media LLC
Date: 18-12-2012
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.ACA.2015.02.063
Abstract: This paper describes a new, efficient and versatile method for the s ling and preconcentration of PAH in environmental water matrices using special hybrid magnetic carbon nanotubes. These N-doped hiphilic CNT can be easily dispersed in any aqueous matrix due to the N containing hydrophilic part and at the same time show high efficiency for the adsorption of different PAH contaminants due to the very hydrophobic surface. After adsorption, the CNT can be easily removed from the medium by a simple magnetic separation. GC/MS analyses showed that the CNT method is more efficient than the use of polydimethylsiloxane (PDMS) with much lower solvent consumption, technical simplicity and time, showing good linearity (range 0.18-80.00 μg L(-1)) and determination coefficient (R(2) > 0.9810). The limit of detection ranged from 0.05 to 0.42 μg L(-1) with limit of quantification from 0.18 to 1.40 μg L(-1). Recovery (n=9) ranged from 80.50 ± 10 to 105.40 ± 12%. Intraday precision (RSD, n=9) ranged from 1.91 to 9.01%, whereas inter day precision (RSD, n=9) ranged from 7.02 to 17.94%. The method was applied to the analyses of PAH in four lake water s les collected in Belo Horizonte City, Brazil.
Publisher: Hindawi Limited
Date: 20-01-2019
DOI: 10.1155/2019/8480468
Abstract: Ischemic stroke is a neurovascular disorder caused by reduced or blockage of blood flow to the brain, which may permanently affect motor and cognitive abilities. The diagnostic of stroke is performed using imaging technologies, clinical evaluation, and neuropsychological protocols, but no blood test is available yet. In this work, we analyzed amino acid concentrations in blood plasma from poststroke patients in order to identify differences that could characterize the stroke etiology. Plasma concentrations of sixteen amino acids from patients with chronic ischemic stroke (n = 73) and the control group (n = 16) were determined using gas chromatography coupled to mass spectrometry (GC-MS). The concentration data was processed by Partial Least Squares-Discriminant Analysis (PLS-DA) to classify patients with stroke and control. The amino acid analysis generated a first model able to discriminate ischemic stroke patients from control group. Proline was the most important amino acid for classification of the stroke s les in PLS-DA, followed by lysine, phenylalanine, leucine, and glycine, and while higher levels of methionine and alanine were mostly related to the control s les. The second model was able to discriminate the stroke subtypes like atherothrombotic etiology from cardioembolic and lacunar etiologies, with lysine, leucine, and cysteine plasmatic concentrations being the most important metabolites. Our results suggest an amino acid biosignature for patients with chronic stroke in plasma s les, which can be helpful in diagnosis, prognosis, and therapeutics of these patients.
Publisher: Informa UK Limited
Date: 06-2003
Publisher: Springer Science and Business Media LLC
Date: 18-01-2021
Publisher: Elsevier BV
Date: 06-2007
DOI: 10.1016/J.JCHROMB.2007.03.023
Abstract: The analysis of exhaled air has several advantages since it is a noninvasive method applicable to a large number of toxic agents, in addition to being a simpler matrix than those of other biological s les such as urine and blood. However, it presents some challenges, such as the necessity of a more sensitive s ling procedure, since the chemical substances eliminated through exhaled air are unchanged in form, not being metabolized, and exhaled compounds are present at extremely low concentrations, i.e. in the nanomolar range. To improve the sensitivity and precision of measurement of the concentration of these substances in exhaled air, the s le usually has to be concentrated before assay by gas chromatography. To this end, the use of the solid-phase microextraction (SPME) technique has been proposed as an efficient s ling method. This paper presents a revision of breath analysis as a biomarker for occupational and environmental exposure to chemicals. The s ling methods and the potential use of SPME for determining chemical substances in exhaled air are discussed.
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 05-2011
DOI: 10.1016/J.CHROMA.2010.11.068
Abstract: The frying of foods in the home can be a cause of indoor pollution due to the formation of acrolein. The emission of acrolein formed during frying in soybean, corn, canola, sunflower and palm oils was studied. A GC/MS method has been developed to determine acrolein in French fries using SPME as the s ling technique after derivatization with 2,4-dinitrophenylhydrazine (DNPH). Optimum SPME conditions included desorption at 250°C for 2min after an adsorption time of 10min at room temperature. The method presented good resolution, repeatability, detection and quantification limits, and linearity of response. French fries were prepared in five different oils with four frying steps. The results showed that changes in acrolein concentration occurred after frying potatoes in different types of oil and at different frying cycles. Potatoes fried in soybean oil contained the lowest concentration of acrolein. Shoestring potatoes contained a lower concentration of acrolein than potato chips and French fries, respectively, because of the higher surface/volume ratio.
Publisher: Elsevier BV
Date: 07-1992
Publisher: Springer Science and Business Media LLC
Date: 17-03-2021
Publisher: Informa UK Limited
Date: 06-2005
DOI: 10.1080/02652030500132893
Abstract: This paper describes the analysis of volatile organic compounds (VOC) in typical Brazilian fruit and fruit juices by a solid-phase microextraction (SPME) method using a capillary gas chromatography system with flame ionization detection and mass spectrometry (GC-MS). A SPME holder with a 100-microm polydimethilsiloxane fibre coating was utilized. The optimal conditions were desorption at 220 degrees C for 1 min, absorption at 50 degrees C for 20 min and 4.00 ml of s le in the headspace vial. The method gave good precision and showed a linear response. More than 100 VOC were identified in the fruit and juices studied by GC-MS. The method was employed to quantify ethanol, naphthalene and benzoic acid in four different species of Brazilian fruit and their juices.
Publisher: Springer Science and Business Media LLC
Date: 04-2020
Publisher: Bentham Science Publishers Ltd.
Date: 07-2010
Publisher: Elsevier BV
Date: 08-2021
Publisher: Hindawi Limited
Date: 05-09-2013
DOI: 10.1155/2013/805678
Abstract: Bile acids derived from cholesterol are produced in the liver, and their analysis is difficult due to their complex natures and their low concentrations in biological fluids. Mixtures of various derivatives, created via conventional heating, are used for such analyses. Microwave radiation is proposed to accelerate the derivatization process. This paper presents a mass fragmentation study and microwave-assisted derivatization (MAD) for the silylation of bile acids (cholic and ursodesoxycholic) prior to gas chromatography and mass spectrometry analysis. The derivatization was performed using the two-step process of methoximation and silylation. The reaction time, power, and quantity of N,O-bis-(trimethylsilyl) trifluoroacetamide (BSTFA) + 1% trimethylchlorosilane (TCMS) were optimized to improve the derivatization. The optimized derivatization conditions required 210 W for 3 min. The MAD method exhibited linearity with respect to cholic acid between 0.78 and 20.0 μ g mL −1 with an LOQ of 0.23 μ g mL −1 and a precision ranging from 1.08% to 9.32% CV. This optimized derivatization method is valid for the analysis of bile acids in different matrices.
Publisher: Informa UK Limited
Date: 02-2013
DOI: 10.1080/03601234.2013.730015
Abstract: The photolytic degradation of diazinon, an organophosphorus pesticide, in aqueous medium under assorted pH values was continuously monitored by direct infusion electrospray ionization mass spectrometry (ESI-MS). The results indicated that the UV radiation was quite efficient in promoting the pesticide degradation at the three pH levels evaluated (5, 7 and 8). The m/z of the most abundant ions observed in the mass spectra (MS), in conjunction with the fragmentation patterns of such ionic species (MS/MS data), made possible the proposition of chemical structures for the main by-products formed. As a result, routes for the photodegradation of diazinon in aqueous solution could thus be suggested. In the assays using Artemia salina (brine shrimp) it was verified that the photodegradation products exhibited much lower toxicity than the primary substrate. Aiming at mimicking the conditions ordinarily found in water treatment plants, an additional series of tests was conducted with a solution containing sodium hypochlorite and diazinon. This solution, when not exposed to UV radiation, exhibited high toxicity against the microorganisms. Under the influence of UV radiation, however, the toxicity rates decreased dramatically. This result is relevant because it points toward the confident application of UV radiation to neutralize the deleterious effects caused by diazinon (and perhaps other organophosphorus pesticides) as well as sodium hypochlorite to the environment.
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 2023
DOI: 10.1016/J.CHEMOSPHERE.2022.136872
Abstract: A risk assessment and a source apportionment of the particulate- and gas-phase PAHs were conducted in a high vehicular traffic and industrialized region in southeastern Brazil. Higher concentrations of PAHs were found during summer, being likely driven by the contributions of PAHs in the vapor phase caused by fire outbreaks during this period. Isomer ratio diagnostic and Principal Component Analysis (PCA) identified four potential sources in the region, in which the Positive Matrix Factorization (PMF) model confirmed and apportioned as gasoline-related (31.8%), diesel-related (25.1%), biomass burning (23.4%), and mixed sources (19.6%). The overall cancer risk had a tolerable value, with ∑CR = 4.6 × 10
Publisher: Elsevier BV
Date: 07-2015
DOI: 10.1016/J.FOODCHEM.2015.01.078
Abstract: Plasticisers are compounds used in the polymer industry to increase the flexibility of plastics. Some of these compounds cause endocrine dysfunction in humans and animals by interfering with the production, release, transport, metabolism, binding or elimination of natural hormones in the body and are therefore recognised as endocrine disruptors. This paper describes cold-fibre solid-phase microextraction as a s ling technique to analyse eight plasticisers in spices and roasted chicken meat stored in plastic bags by gas chromatography-mass spectrometry. Limits of detection for this method ranged from 0.01 to 0.18 μg kg(-)(1). Diisobutyl phthalate and dibutyl phthalate were found in the s les of spices and roasted chicken meat. The highest concentrations of plasticisers were found in the spices used to cook the chicken meat.
Publisher: Springer Science and Business Media LLC
Date: 07-06-2020
Publisher: Springer Science and Business Media LLC
Date: 05-2003
Publisher: Elsevier BV
Date: 04-2009
DOI: 10.1016/J.CHROMA.2008.11.012
Abstract: The determination of polycyclic aromatic hydrocarbon (PAH) metabolites in human urine is the method of choice for assessing exposure to carcinogenic compounds. The objective of this study was the development of a comprehensive two-dimensional gas chromatography (GCxGC) method using a flame ionisation detector (FID) to simultaneously determine 10 hydroxylated PAH. The method was based on enzymatic deconjugation, liquid-liquid extraction, and trimethylsilyl (TMS) derivatization of the analytes by microwave heating. Satisfactory separation was achieved. The coefficient of variance was 3.8-12.8%. LOD was 0.03-0.18 microg/L, and LOQ was 0.1-0.5 microg/L. The mean recovery was 76%. The method was applied to the analysis of urine from smokers and non-smokers.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.JCHEMNEU.2013.11.002
Abstract: The analysis of amino acid levels is crucial for neuroscience studies because of the roles of these molecules as neurotransmitters and their influence on behavior. The present study describes the distribution and levels of 16 amino acids (alanine, asparagine, aspartic acid, cysteine, glycine, glutamic acid, isoleucine, leucine, lysine, methionine, phenylalanine, proline, sarcosine, serine, valine, and threonine) in brain tissues (prefrontal cortex, striatum, hippoc us and cerebellum) and the serum. Neurochemical analysis was performed on Wistar rats and C57BL/6 mice using an efficient method for extraction, a fast microwave-assisted derivatization and gas chromatography-mass spectrometry analysis. The amino acid concentration varied across brain regions for 14 of the 16 analyzed molecules, with detection limits ranging from 0.02±0.005μmolL(-1) to 7.07±0.05μmolL(-1). In rats, the concentrations of alanine, glycine, methionine, serine and threonine were higher in prefrontal cortex than in other areas, whereas in mice, the concentrations of glutamic acid, leucine and proline were highest in the hippoc us. In conclusion, this study provides a cerebral profile of amino acids in brain regions and the serum of rats and mice.
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.CHROMA.2018.11.046
Abstract: Polycyclic aromatic hydrocarbons (PAHs) are food contaminants besides, their oxygenated (oxy-PAHs) and nitrated (nitro-PAHs) derivatives have also been detected in some foods. This is worrying because these derivatives may be more toxic than PAHs. This study presents a new method for the determination of PAHs and their oxygenated and nitrated derivatives in coffee brew. The analytes were extracted by cold fiber solid phase microextraction (CF-SPME) with analysis by gas chromatography/mass spectrometry. The developed method presented good precision with intra-assay and inter-assay, ranged from 4.5 to 16.4%, and from 9.8 to 19.8%, respectively. Recovery ranged from 82.1 to96.3% and linearity showed good adjustment presenting determination coefficients (R
Publisher: Elsevier BV
Date: 04-2009
DOI: 10.1016/J.CHROMA.2008.10.061
Abstract: Comprehensive two-dimensional gas chromatography (GCxGC) was applied to the study of cachaça production. Effects of bidistillation, and the use of charcoal filtration in the production of artisan cachaça, as well as the effects of multi-distillation on volatile products in commercial cachaça were investigated. Volatile compounds were collected and concentrated onto a polyacrylate solid-phase microextraction fibre, and analyzed using GCxGC on a non-polar (BPX5)-polar (BP20) column set. More than 100 compounds, comprising various homologous series were tentatively identified using MS library matching and comparison with retention indices. Phthalate organic contamination following the use of ion exchange resin for removal of copper ion was evident. Charcoal successfully removes this contamination product. Prediction of compounds within particular homologous series aids component identification.
Publisher: Elsevier BV
Date: 05-2011
DOI: 10.1016/J.CHROMA.2010.10.105
Abstract: Polycyclic aromatic hydrocarbons (PAH) from ambient air particulate matter (PM) were analyzed by a new method that utilized direct immersion (DI) and cold fiber (CF) SPME-GC/MS. Experimental design was used to optimize the conditions of extraction by DI-CF-SPME with a 100μm polydimethylsiloxane (PDMS) fiber. The optimal conditions included a 5min equilibration at 70°C time in an ultrasonic bath with an extraction time of 60min. The optimized method was validated by the analysis of a NIST standard reference material (SRM), 1649b urban dust. The results obtained were in good agreement with certified values. PAH recoveries for reference materials were between 88 and 98%, with a relative standard deviation ranging from 5 to 17%. Detection limits (LOD) varied from 0.02 to 1.16ng and the quantification limits (LOQ) varied from 0.05 to 3.86ng. The optimized and validated method was applied to the determination of PAH from real particulate matter (PM10) and total suspended particulate (TPS) s les collected on quartz fiber filters with high volume s lers.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4AN00583J
Abstract: Metabolome analysis involves the study of small molecules that are involved in the metabolic responses that occur through patho-physiological changes caused by genetic stimuli or chemical agents.
Publisher: Informa UK Limited
Date: 20-03-2012
Publisher: Wiley
Date: 29-08-2006
DOI: 10.1002/RCM.2665
Abstract: The headspace compositions of 13 pepper and peppercorn s les of different species, colloquially also referred to as pepper, were analyzed, and more than 300 compounds were tentatively characterized by means of comprehensive two-dimensional gas chromatography in tandem with flame ionization detection, quadrupole mass spectrometric detection and time-of-flight mass spectrometric detection (GC x GC-FID, GC x GC/qMS and GC x GC/TOFMS, respectively). The analysis of volatile organic compounds (VOCs) was performed after solid-phase microextraction (SPME) using a 75-microm PDMS/DVB fibre. Fingerprint comparison between the three techniques permitted peaks to be assigned in the GC x GC-FID experiment based on the analogous MS analysis, taking into account retention shifts arising from method variations. When using GC x GC/TOFMS, about five times more peaks were identified than in GC x GC/qMS. Retention indices for all peaks were calculated in the bi-dimensional column set comprising of a 5% phenyl polysilphenylene-siloxane primary column and a polyethylene glycol second column. The spectra obtained by both mass detection techniques (qMS and TOFMS) give very similar results when spectral library searching was performed. The majority of the identified compounds eluted as pure components as a result of high-resolution GC x GC separations, which significantly reduces co-elution, and therefore increases the likelihood that pure spectra can be obtained. The differences between TOFMS and qMS (in fast scanning mode) spectra were generally small. Whilst spectral quality and relative ion ratios across a narrow peak (e.g. w(b) approximately 100-150 ms) do vary more for the fast peaks obtained in GC x GC/qMS operation, than with TOFMS, in general adequate spectral matching with the library can be achieved.
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.ENVRES.2017.03.025
Abstract: This paper shows the use of exhaled air as a biomonitoring method to assess perchloroethylene (PERC) environmental and occupational exposure. A sensitive, fast, and solvent free analytical method was developed to determine PERC in ambient and exhaled air of in iduals occupationally exposed. The developed method used cold fiber solid phase microextraction (CF-SPME) as the s ling technique, and a standard permeation method to simulation of air matrix. The analysis were conducted by gas chromatography coupled to mass spectrometry (GC/MS). The methods were validated and were found to be precise, linear and sensitive for environmental and biological monitoring. The developed methods were applied to twenty-seven s ling points spread across Belo Horizonte city, Brazil, twenty four dry cleaners, an electroplating industry, a research laboratory, and an automotive paint preparation shop. The results of ambient air analyses ranging from 14.0 to 3205.0µgm
Publisher: Sociedade Brasileira de Quimica (SBQ)
Date: 2013
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.CHROMA.2015.02.016
Abstract: Bile acids (BAs) are derived from cholesterol and produced in the liver. The most abundant bile acids in humans are usually conjugated with glycine and taurine and are ided into primary BAs such as cholic acid (CA) and chenodeoxycholic acid (CDCA) and secondary BAs like deoxycholic acid (DCA), lithocholic acid (LCA) and ursodeoxycholic acid (UDCA). The differences amongst in idual bile acids (BAs) are significant in order to distinguish different pathological processes and exposure to chemical compounds. Hollow fiber based liquid-phase microextraction (HF-LPME) is a technique that combines s le cleansing, extraction and the concentration of analytes, where a hydrophobic porous capillary membrane is impregnated with an organic extraction solvent and the lumen is filled with microliters of a phase acceptor both organic by nature. The aim of this study was to develop a new method to extract bile acids from plasma through HF-LPME of two phases (octanol as the acceptor phase) using LCMS-IT-TOF. The optimized two-phased LPME procedure for the extraction of bile acids showed limits of detection 1.0 μg L(-1) and limits of quantification of 5.0 μg L(-1). The intra-assay precision ranged from 2.1 to 11.9%. The method developed was linear over the range of 5.0-200.0 μg L(-1) for all analytes. The hollow-fiber liquid-phase microextraction method was applied to human plasma from workers exposed to organic and halogenated solvents and also to unexposed volunteers. The method is simple, low cost and it does not require large amounts of organic solvents, therefore it is quite suitable for the analysis of bile acids exposed to hepatotoxic compounds.
Publisher: InTech
Date: 21-01-2011
DOI: 10.5772/14148
Publisher: FapUNIFESP (SciELO)
Date: 2022
Publisher: Springer Science and Business Media LLC
Date: 09-05-2022
Publisher: Informa UK Limited
Date: 27-03-2017
Publisher: Springer Science and Business Media LLC
Date: 20-10-2009
DOI: 10.1007/S00216-009-3206-X
Abstract: Benzene is classified as a Group I carcinogen by the International Agency for Research on Cancer (IARC). The risk assessment for benzene can be performed by monitoring environmental and occupational air, as well as biological monitoring through biomarkers. The present work developed and validated methods for benzene analysis by GC/MS using SPME as the s ling technique for ambient air and breath. The results of the analysis of air in parks and avenues demonstrated a significant difference, with average values of 4.05 and 18.26 microg m(-3), respectively, for benzene. S ling of air in the occupational environment furnished an average of 3.41 and 39.81 microg m(-3). Moreover, the correlations between ambient air and expired air showed a significant tendency to linearity (R (2) = 0.850 and R (2) = 0.879). The results obtained for two groups of employees (31.91 and 72.62 microg m(-3)) presented the same trend as that from the analysis of environmental air.
Publisher: Wiley
Date: 26-09-2013
Publisher: Springer Science and Business Media LLC
Date: 29-08-2020
Publisher: Hindawi Limited
Date: 2016
DOI: 10.1155/2016/7058709
Abstract: This paper describes a simple and quick method for s ling and also for carrying out the preconcentration of pesticides in environmental water matrices using two-phased hollow fiber liquid phase microextraction (HF-LPME). Factors such as extraction mode, time, solvents, agitation, and salt addition were investigated in order to validate the LPME method. The following conditions were selected: 6 cm of polypropylene hollow fiber, ethyl octanoate as an acceptor phase, and extraction during 30 min under stirring at 200 rpm. The optimized method showed good linearity in the range of 0.14 to 200.00 μ g L −1 the determination coefficient ( R 2 ) was in the range of 0.9807–0.9990. The LOD ranged from 0.04 μ g L −1 to 0.44 μ g L −1 , and LOQ ranged from 0.14 μ g L −1 to 1.69 μ g L −1 . The recovery ranged from 85.17% to 114.73%. The method was applied to the analyses of pesticides in three environmental water s les (a spring and few streams) collected in a rural area from the state of Minas Gerais, Brazil.
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.JCHROMB.2008.02.023
Abstract: The determination of benzene in exhaled air has contributed for the increase in the use of breath analysis in biological monitoring. This paper describes SPME as a s ling technique for determining benzene in exhaled air by GC-MS. A system was developed to generate a gaseous benzene standard by a permeation method to accomplish the breath analyses. The method presented good resolution, repeatability (the mean of %RSD values for intra-day measurements was 6.3), sensitivity (2.4 and 3.1 ppb for LOD and LOQ, respectively), and linearity of response (R(2)=0.994). After optimizing the conditions, analyses of real s les were performed on two groups (exposed and not exposed to benzene). The results presented an average of 8.2 ppb for the control group and 25.3 ppb for the exposed group.
Publisher: Informa UK Limited
Date: 13-09-2021
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.JCHROMB.2013.05.014
Abstract: The determination of the concentrations of l-amino acids in cerebrospinal fluid (CSF) has been used to gain biochemical insight into central nervous system disorders. This paper describes a microwave-assisted derivatization (MAD) method using N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) as a derivatizing agent for determining the concentrations of l-amino acids in human CSF by gas chromatography with mass spectrometry (GC/MS). The experimental design used to optimize the conditions showed that the optimal derivatization time was 3min with a microwave power of 210W. The method showed good performance for the validation parameters. The sensitivity was very good, with limits of detection (LODs) ranging from 0.01μmolL(-1) to 4.24μmolL(-1) and limits of quantification (LOQs) ranging from 0.02 to 7.07μmolL(-1). The precision, measured using the relative standard deviation (RSD), ranged from 4.12 to 15.59% for intra-day analyses and from 6.36 to 18.71% for inter-day analyses. The coefficients of determination (R(2)) were above 0.990 for all amino acids. The optimized and validated method was applied to the determination of amino acid concentrations in human CSF.
Publisher: Sociedade Brasileira de Quimica (SBQ)
Date: 1996
Publisher: Oxford University Press (OUP)
Date: 03-2002
DOI: 10.1093/CHROMSCI/40.3.122
Abstract: A solid-phase microextraction (SPME) s ling method is developed to evaluate indoor exposure to benzene, toluene, ethylbenzene, xylene, and styrene with gas chromatography and flame ionization detection for quantitative analysis. An SPME holder with a 100-pm polydimethylsiloxane (PDMS) and 65-pm PDMS- inylbenzene fiber coating is tested in different air relative humidity conditions. The method gives good resolution, shows a linear response, is repeatable, and presents high sensitivity. This method is compared with National Institute of Occupational Safety and Health (NIOSH) active s ling.
Publisher: American Chemical Society
Date: 30-09-2008
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.JPBA.2019.04.048
Abstract: Endocrine disrupting chemicals (EDCs) such as phthalates and bisphenol A (BPA) are substances that may interfere with the actions of endogenous hormones and may be associated with estrogen-related diseases such as endometriosis. This paper describes a case-control study to evaluate the relationship between endometriosis and phthalates and BPA exposure, through biomarkers analysis in urine. The biomarkers of exposure analyzed were metabolites mono-methyl phthalate, mono-isobutyl phthalate (MiBP), mono-butyl phthalate, mono-cyclohexyl phthalate, mono-(ethylhexyl) phthalate, mono-isononyl phthalate, mono-octyl phthalate (MOP), mono-benzyl phthalate and BPA. Urine s les were collected from women aged 18-45 years old. The Study group (n = 30) and Control group (n = 22) were composed of women using as criteria confirmation of endometriosis by videolaparoscopy surgery with histological diagnosis and the absence of the disease, respectively. The analytical method used liquid phase microextraction with determination by gas chromatography coupled to mass spectrometry. The concentrations of biomarkers were adjusted by the creatinine concentration in urine s les of the two groups. The values obtained for the Study Group were compared with the values obtained for the Control Group. The chi-square test and Odds Ratio were used to compare dichotomized phthalate metabolites and BPA metabolite by endometriosis. All nine metabolites were found in different concentrations in the urine s les in both groups The phthalate metabolites that had the highest concentrations, were MOP and MiBP, in which the values of 670 μg g
Publisher: Elsevier BV
Date: 12-2023
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.TALANTA.2017.02.054
Abstract: This article describes a simple, efficient, and versatile magnetic carbon nanotubes (MCNT) method for s ling and pre-concentration of pesticides in environmental water s les. The multi-walled magnetic carbon nanotubes were obtained by chemical deposition vapor (CVD) process. The MCNTs structures are formed of hydrophobic and hydrophilic fractions that provide great dispersion at any water matrix allowing simultaneously a high efficiency of pesticides sorption. Following the extraction, analytes were desorbed with minor amounts of solvent and analyzed by gas chromatography coupled mass spectrometry (GC/MS). The parameters amount of MCNTs used to extraction, desorption time, and desorption temperature were optimized. The method showed good linearity with determination coefficients between 0.9040 and 0.9733. The limits of detection and quantification were ranged between 0.51 and 2.29µgL
Publisher: Wiley
Date: 02-2006
Abstract: This paper proposes a solid-phase microextraction (SPME) method for the passive s ling and determination of N,N-dimethylacetamide (DMA) and N,N-dimethylformamide (DMF) in air by capillary GC with flame ionization detection. The optimized conditions for SPME method were grab s ling, polydimethylsiloxane/ inylbenzene fiber, extraction for 90 min at 25 +/- 2 degrees C, desorption for 3 min at 220 degrees C, and relative humidity 45 +/- 2%. Under these conditions, the method presented good linearity (R = 0.996), repeatability (%RSD 2.79 and 9.85 for DMF and DMA, respectively), and detection limit (0.021 and 0.024 mg/m3 for DMF and DMA, respectively).
Publisher: FapUNIFESP (SciELO)
Date: 08-2005
Publisher: Informa UK Limited
Date: 07-2006
DOI: 10.1080/03601230600634745
Abstract: Solid phase microextraction (SPME) was used for the extraction of residual coumaphos and dichlorvos in whole milk. The residues were analyzed by capillary gas chromatography equipped with nitrogen phosphorus detector (GC-NPD). A manual SPME holder with a 100-microm polyacrylate fiber was used. The optimized conditions for extraction by SPME method were: s le agitation, absorption temperature of 30 degrees C, absorption time of 40 min, desorption time of 10 min, and s le volume was 16.0 mL in the vial. Under these conditions, the calibration graphs were linear in the range of 0.17 microgL-1 to 1.75 microgL-1 for coumaphos and 0.69 microgL-1 to 6.90 microgL-1 for dichlorvos. Precision was good with RSD values of 13% for coumaphos and 14% for dichlorvos. The detection limits (LOD) were 0.060 microgL-1 for dichlorvos and 0.052 for coumaphos. The quantification limits (LOQ) were 0.086 microgL-1 for dichlorvos and 0.066 microgL-1 for coumaphos. The results obtained in this study suggest that SPME is a suitable technique for residual pesticide analysis of milk. The data demonstrate that particular OP pesticides used in dairy farming in the region of Minas Gerais were found to contaminate cow whole milk, and the residues are not removed by treating the milk by boiling.
Publisher: Oxford University Press (OUP)
Date: 07-2000
DOI: 10.1093/CHROMSCI/38.7.315
Abstract: A headspace solid-phase microextraction (HS-SPME) method is developed for the determination of styrene in drinking water. Gas chromatography (GC)-mass spectrometry is utilized for qualitative analysis. A manual SPME holder with 85-microm polyacrylate coating is used to extract the styrene from water, which is determined to have good linearity (correlation coefficient r = 0.9999 for 1.00-100.00 microg/L range), a relative standard deviation of 1.9%, and a detection limit of 0.30 microg/L. This method is compared with a classical headspace GC method.
Publisher: Informa UK Limited
Date: 29-07-2015
Publisher: Springer International Publishing
Date: 2016
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.CHROMA.2015.02.029
Abstract: Fruit spirits have been produced and consumed throughout the world for centuries. However, the aroma composition of banana spirits is still poorly characterised. We have investigated the aroma-impact compounds of the banana Terra spirit for the first time, using multidimensional gas chromatography (MDGC and GC × GC) in a multi-hyphenated system - i.e., coupled to flame ionisation detection (FID), mass spectrometry (MS), and olfactometry (O). Solid-phase microextraction (SPME) was used to isolate the headspace aroma compounds of the banana spirit. The detection frequency (DF) technique was applied and aroma regions, detected in the first column separation at >60% Nasal Impact Frequency (NIF), were screened as target potent odour regions in the s le. Using a polar/non-polar phase column set, the potent odour regions were further subjected to MDGC separation with simultaneous O and MS detection for correlation of the aroma perception with MS data for in idual resolved aroma-impact compounds. GC-O analysis enabled 18 aroma-impact regions to be located as providing volatiles of interest for further study for ex le, those comprising perceptions of flower, whisky, green, amongst others. Compounds were tentatively identified through MS data matching and retention indices in both first and second dimensions. The principal volatile compounds identified in this work, which are responsible for the characteristic aroma of the banana spirit, are 3-methylbutan-1-ol, 3-methylbutan-1-ol acetate, 2-phenylethyl acetate and phenylethyl alcohol. This is the first such study to reveal the major aroma compounds that contribute to banana spirit aroma.
Publisher: Wiley
Date: 17-05-2012
DOI: 10.1002/ETC.1853
Abstract: Polycyclic aromatic hydrocarbons (PAHs) were analyzed from ambient air particulate matter <10 µm (PM(10) ) and the total suspended particulate (TSP) phase continuously for a period of six months (May-October 2010) at five s ling sites located in the urban area of Divinópolis (Minas Gerais), southeastern Brazil, near iron and steel mills. The carcinogenic potency of priority PAHs relative to benzo[a]pyrene was estimated for a period of six months. Benzo[a]pyrene equivalents were 7.52 ng/m(3) for the study period. The estimated risk of lifetime lung cancer was 6.5 × 10(-4) . A model based on the diagnostic ratio and principal component analysis was applied for source apportionment. Considering the entire study period, the burning of biomass and fuel oil accounted for about 70% of the PAH profile. An inventory was performed during the monitoring period, with 37 companies representing major industries located in the urban area. The observations were consistent with the distribution of sources and indicated that the iron and steel sector was the largest contributor.
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.ACA.2022.340405
Abstract: Phthalic acid esters (PAEs) are considered endocrine disruptors and potential carcinogens. Consequently, efficient and accurate environmental monitoring of trace levels of these organic pollutants is necessary to protect the population against their hazardous effects. Passive s ling techniques have gained notoriety for environmental monitoring and have been proven highly sensitive to temporal variations. This study developed a miniaturized passive s ling device (MPSD) based on hollow fiber liquid-phase microextraction (HF-LPME). The devices were calibrated in the laboratory using an automated calibration system. The results demonstrated the first-order uptake ranges for Diethyl phthalate (DEP), Diisobutyl phthalate (DiBP), Dibutyl phthalate (DBP), Benzyl butyl phthalate (BBP) and Bis(2-ethylhexyl phthalate) (DEHP) between 30 min and 24 h with s ling rates equivalent to 0.009 0.021 0.033 0.085 and 0.003 mL h
Publisher: FapUNIFESP (SciELO)
Date: 08-1997
Publisher: Elsevier BV
Date: 05-2010
Publisher: Future Science Ltd
Date: 11-2017
Abstract: Aim: The increasing use of cocaine (COC) during breastfeeding has led to growing concern about exposure of infants. Therefore, to study this exposure, a new method to analyze COC and benzoylecgonine in breast milk was developed. Methodology: A new extraction method was used for the first time to analyze COC and its major metabolite, benzoylecgonine, in breast milk using magnetic carbon nanotubes partially doped with nitrogen. Results: The calibration curves were linear in the range 5.0–180.0 ng ml -1 . The limit of quantification was 5.0 ng ml -1 . Coefficients of variation were between 3.2 and 13.9%. Recovery was between 89.6 and 99.2%. Conclusion: The proposed method is simple, efficient and suitable to determine analytes in breast milk.
Publisher: Hindawi Limited
Date: 26-04-2023
DOI: 10.1155/2023/5561490
Abstract: The present study describes an efficient analytical method for analyzing apple pesticide residues. This novel approach employs ultrasound-assisted cleaning (UAC), solid-phase microextraction (SPME), and gas chromatography/mass spectrometry (GC-MS). A fiber coating with carbon nanomaterials (CNMs) was used for the extraction process. The methodology underwent extraction process optimization and analytical method validation. Moreover, its applicability for detecting pesticides in apples was evaluated. The validation showed satisfactory results with linearity coefficients greater than 0.99 (R2 0.99) and linear working ranges from 0.5 ng·g−1 to 300.0 ng·g−1. The limits of detection and quantification (LODs and LOQs) ranged from 0.1 ng·g−1 to 0.3 ng·g−1 and from 0.5 ng·g−1 to 0.7 ng·g−1, respectively. The calculated recovery values ranged from 79% to 98%. The precision presented a relative standard deviation (RSD) lower than 14%. The validated method was applied to apple s les acquired from different markets and fruit stands in Belo Horizonte, Minas Gerais, Brazil. Organophosphate pesticides typically used in Brazilian apple production areas were detected in some s les. This study demonstrates the utility of UAC and CNM microextraction as an effective and highly efficient approach for analyzing pesticides in apples.
Publisher: Elsevier BV
Date: 15-01-2008
DOI: 10.1016/J.TALANTA.2007.07.021
Abstract: Cachaça s les were studied by means of comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GCxGC/TOFMS) during the fermentation process and after ageing in different wood materials. The analyses of the aroma compounds were performed after headspace-solid phase microextraction method (HS-SPME) using an 85microm polyacrylate (PA) fibre. Fingerprint monitoring of the distillation process allowed the easy determination of the turning points of the process and high-resolution comparison of cabeça (head), coração (core) and cauda (tail) fractions. The ageing process in different wood materials was well characterised through fingerprint similarity observations in the absence of a suitable metric for expressing the overall similarity, here we use a visual and retention time comparison to identify co-incident peaks and those that differ between s les. For quality control purposes, a simple observation of the contour plots obtained can thus allow the identification of the type of wood used in the ageing process, and the process of ageing, without further statistical treatment or peak identifications. In this manner, peaks, which discriminated most between the different mixtures studied were readily found, i.e. unique compounds were identified in each stage of the distillation process. Approximate first dimension linear retention indices (LRI) for these identified compounds were calculated in a bi-dimensional polar/non-polar column set in the GCxGC experiment and were used in conjunction with mass spectral library searching for tentative identification. Along the progression of the distillation process, 70 compounds appear to visually discriminate between s les and their retention indices are indicated, presenting good correlation with literature data.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Springer Science and Business Media LLC
Date: 13-01-2010
Publisher: Sociedade Brasileira de Quimica (SBQ)
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 12-1993
DOI: 10.1007/BF02274111
Publisher: Wiley
Date: 21-01-2020
DOI: 10.1002/AUR.2267
Publisher: FapUNIFESP (SciELO)
Date: 10-2005
Publisher: American Chemical Society (ACS)
Date: 14-07-2001
DOI: 10.1021/JF000896R
Abstract: A headspace solid-phase microextraction (SPME) method was developed for the determination of secondary compounds from Brazilian sugar cane spirits, or cachaça, by GC-FID. An SPME holder with an 85 microm polyacrylate coating was utilized. The novel method is compared with an optimized method: liquid-liquid extraction (LLE). Both methods showed good linearity, but the repeatability for analyses done with the SPME technique (%RSD = 1.8-3.9) was better than for those done with LLE (%RSD = 10.3-11.7). The concentrations of the analytes obtained in the analysis of 12 cachaça s les with the SPME technique were higher than those obtained with LLE. In the SPME method the extraction wastes are smaller. Cachaça s les were qualitatively analyzed for GC-MS.
No related grants have been discovered for Zenilda Cardeal.