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ABSTRACT: Acrylonitrile is a highly important industrial chemical with a high production volume worldwide, especially in the plastics industry. It is classified as a possible human carcinogen by the International Agency for Research on Cancer (IARC group 2B). During metabolism of acrylonitrile, the genotoxic metabolite cyanoethylene-epoxide is formed. The urinary mercapturic acids of acrylonitrile, namely N-acetyl-S-(2-cyanoethyl)-L-cysteine (CEMA) and cyanoethylene-epoxide, namely N-acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (CHEMA) are specific biomarkers for the determination of individual internal exposure to acrylonitrile and its highly reactive metabolite. We have developed and validated a sensitive method for the accurate determination of CEMA and CHEMA in human urine with a multidimensional LC/MS/MS-method using deuterium-labelled analogues for both analytes as internal standards. Analytes were stripped from urinary matrix by online extraction on a restricted access material, transferred to the analytical column and determined by tandem mass spectrometry. The limit of quantification (LOQ) for CEMA and CHEMA was 1 μg/L urine and allowed to quantify the background exposure of the (smoking) general population. Precision within and between series for CHEMA ranged from 2.6 to 8.0% at four concentrations ranging from 8.3 to 86 μg/L urine, mean accuracy was between 94 and 100%. For CEMA, precision within and between series ranged from 2.4 to 14.5% at four concentrations ranging from 15.1 to 196 μg/L urine, mean accuracy was between 91 and 104%. We applied the method to spot urine samples of 83 subjects of the general population with no known occupational exposure to acrylonitrile. Median levels (range) for CEMA and CHEMA in urine samples of non-smokers (n=47) were 1.9 μg/L (<1-16.4 μg/L) and<1 μg/L (<1-3 μg/L), while in urine samples of smokers (n=36), median levels were 184 μg/L (2-907 μg/L) and 29.3 μg/L (<1-147 μg/L), respectively. Smokers showed a significantly higher excretion of both acrylonitrile metabolites (p<0.001). Due to its automation and high sensitivity, our method is well suited for application in experimental studies on acrylonitrile metabolism or occupational studies.
Talanta 08/2012; 98:211-9. · 3.79 Impact Factor
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ABSTRACT: BACKGROUND: Metal active gas welding (MAG) is a widely-used welding technique resulting in high emissions of welding fume particles. This study investigated whether short-term exposure to these fume particles results in changes in lung function and early stages of inflammatory reactions. METHODS: Twelve healthy, young male subjects were exposed to MAG fumes for 6 h with three different exposure concentrations in a three-fold cross-over study design. Exposure was performed in the "Aachen Workplace Simulation Laboratory" under controlled conditions with constant fume concentration. Fume concentrations were 0, 1, and 2.5 mg m(-3) in randomized order. Before and after each exposure, spirometry, and impulse oscillometry were performed and breath condensate samples were collected in order to quantify inflammatory markers like Nitrate, Nitrite, Nitrotyrosine, Hydroxyprolin and Malondialdehyde. RESULTS: A significant dependency on the exposure concentration could not be established for any of the endpoint parameters. CONCLUSION: In healthy, young subjects neither changes in spirometry nor changes in inflammatory markers measured in exhaled breath condensate could be detected after short-term exposure.
Archiv für Gewerbepathologie und Gewerbehygiene 02/2012; · 1.89 Impact Factor
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ABSTRACT: Styrene is one of the most important industrial chemicals, with an enormously high production volume worldwide. The urinary mercapturic acids of its metabolite styrene-7,8-oxide, namely N-acetyl-S-(2-hydroxy-1-phenylethyl)-L-cysteine (PHEMA 1) and N-acetyl-S-(2-hydroxy-2-phenylethyl)-L-cysteine (PHEMA 2), are specific biomarkers for the determination of individual internal exposure to this highly reactive intermediate of styrene. We have developed and validated a fast, specific and very sensitive method for the accurate determination of the sum of phenylhydroxyethyl mercapturic acids (PHEMAs) in human urine with an automated multidimensional liquid chromatography-tandem mass spectrometry method using (13)C(6)-labelled PHEMAs as internal standards. Analytes were stripped from the urinary matrix by online extraction on a restricted access material, transferred to the analytical column and subsequently determined by tandem mass spectrometry. The limit of quantification (LOQ) for the sum of PHEMAs was 0.3 microg/L urine and allowed us to quantify the background exposure of the (smoking) general population. Precision within series and between series ranged from 1.5 to 6.8% at three concentrations ranging from 3 to 30 microg/L urine; the mean accuracy was between 104 and 110%. We applied the method to spot urine samples from 40 subjects of the general population with no known occupational exposure to styrene. The median levels (range) for the sum of PHEMAs in urine of non-smokers (n = 22) were less than 0.3 microg/L (less than 0.3 to 1.1 microg/L), whereas in urine of smokers (n = 18), the median levels were 0.46 microg/L (less than 0.3 to 2.8 microg/L). Smokers showed a significantly higher excretion of the sum of PHEMAs (p = 0.02). Owing to its automation and high sensitivity, our method is well suited for application in occupational or environmental studies.
Analytical and Bioanalytical Chemistry 08/2010; 397(8):3563-74. · 3.78 Impact Factor
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ABSTRACT: To determine whether the occupational exposure of hairdressers to permanent hair dyes can be quantified by the use of biological monitoring of urinary aromatic diamines as one of the main constituents and to compare these levels to those recently determined in persons after personal application of hair dyes.
Fifty-two hairdressers (40 female and 12 male) from 16 hairdresser salons in and around the city of Aachen took part in this field study. Subjects were asked to document all operations associated with possible exposure to permanent hair dyes like mixing colour, application of colour, washing after dyeing, and cutting of freshly coloured hair. Excretion of aromatic diamines 2,5-toluylene diamine (2,5-TDA) and p-phenylene diamine (p-PDA) as main constituents of commercially available hair dyes was measured in urine samples using a highly specific and accurate GC/MS-method. Urine samples were taken at 5 points of time during the work week: pre-shift before the start of the work week, pre- and post-shift on the third day of the work week and finally pre- and post-shift on the last day of a work week in order to meet different workloads and possible accumulative effects over the week. Nineteen persons matched for age served as a control group and gave spot urine samples.
Although the levels were generally low, we could determine a significantly higher internal exposure to 2,5-TDA in hairdressers (medians ranged from <0.2 μg/g creatinine up to 1.7 μg/g creatinine at various sampling times, with a maximum of 155.8 μg/g creatinine) compared to the control group (median <0.2 μg/g creatinine, maximum 3.33 μg/g creatinine). At the same time, p-PDA was detectable only in selected cases in the group of hairdressers but not in the control group. Overall, there was neither an intra-shift effect seen nor an effect across the work week. There was also no significant difference in urinary excretion of participants who reported wearing protective gloves compared to those who reported not wearing protective gloves.
The internal exposure to aromatic diamines in hairdressers using permanent hair dyes can be determined using biological monitoring. The extent of exposure is low compared to subjects after personal application of hair dyes, who excreted more than 200 times higher amounts of aromatic diamines. This slight work-related exposure might be reduced by the strict adherence to the use of suitable gloves as well as long-sleeved clothing.
Archiv für Gewerbepathologie und Gewerbehygiene 05/2010; 84(3):287-92. · 1.89 Impact Factor
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ABSTRACT: Haemoglobin adducts are highly valuable biomarkers of cumulative exposure to carcinogenic substances. We have developed and applied an analytical method for the simultaneous quantification of five haemoglobin adducts of important occupational and environmental carcinogens. The N-terminal adducts were determined with gas chromatography as pentafluorophenylthiohydantoine derivatives according to the modified Edman-procedure and subsequent acetonization of the glycidamide adduct N-(R,S)-2-hydroxy-2-carbamoylethylvaline (GAVal). The use of self-synthesized labelled internal standards in combination with tandem mass spectrometry using negative chemical ionisation guarantees both high accuracy and sensitivity of our determination. The limit of detection for N-2-hydroxyethylvaline (HEVal), N-(R,S)-2-hydroxypropylvaline (HPVal), N-2-carbamoylethylvaline (AAVal) and N-(R,S)-2-hydroxy-2-carbamoylethylvaline (GAVal) was 2 pmol/g globin, for N-2-cyanoethylvaline (CEVal) it was determined as 0.5 pmol/g globin, which was sufficient to determine the background levels of these adducts in the non-smoking general population. The between-day-precision for all analytes using a human blood sample as quality control material ranged from 4.7 to 12.3%. We investigated blood samples of a small group (n=104) of non-smoking persons of the general population for the background levels of these haemoglobin adducts. The median values for HEVal, HPVal, CEVal, AAVal and GAVal in a group of 92 non-smoking persons were 18.1, 4.1, <0.5, 29.9 and 35.2 pmol/g globin, respectively. The adduct levels in 12 persons reporting exposure to passive smoke at home were similar for most adducts with median values of 17.2, 4.1, 1.0, 24.9 and 29.7 pmol/g globin for HEVal, HPVal, CEVal, AAVal and GAVal, respectively. Our results point to an elevated uptake of acrylonitrile caused by passive smoking as indicated by higher levels of the corresponding haemoglobin adduct CEVal.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 12/2009; 878(27):2467-73. · 2.78 Impact Factor
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ABSTRACT: 1,3-Butadiene and acrylonitrile are important industrial chemicals that have a high production volume and are ubiquitous environmental pollutants. The urinary mercapturic acids of 1,3-butadiene and acrylonitrile-N-acetyl-S-(3,4-dihydroxybutyl)cysteine (DHBMA) and MHBMA (an isomeric mixture of N-acetyl-S-((1-hydroxymethyl)-2-propenyl)cysteine and N-acetyl-S-((2-hydroxymethyl)-3-propenyl)cysteine) for the former and N-acetyl-S-2-cyanoethylcysteine (CEMA) for the latter-are specific biomarkers for the determination of individual internal exposure to these chemicals. We have developed and validated a fast, specific, and very sensitive method for the simultaneous determination of DHBMA, MHBMA, and CEMA in human urine using an automated multidimensional LC/MS/MS method that requires no additional sample preparation. Analytes are stripped from urinary matrix by online extraction on a restricted access material, transferred to the analytical column, and subsequently determined by tandem mass spectrometry using labeled internal standards. The limits of quantification (LOQs) for DHBMA, MHBMA, and CEMA were 10 microg/L, 2 microg/L, and 1 microg/L urine, respectively, and were sufficient to quantify the background exposure of the general population. Precision within series and between series for all analytes ranged from 5.4 to 9.9%; mean accuracy was between 95 and 115%. We applied the method on spot urine samples from 210 subjects from the general population with no occupational exposure to 1,3-butadiene or acrylonitrile. A background exposure of the general population to acrylonitrile was discovered that is basically influenced by individual exposure to passive smoke as well as active smoking habits. Smokers showed a significantly higher excretion of MHBMA, whereas DHBMA levels did not differ significantly. Owing to its automation, our method is well suited for application in occupational or environmental studies.
Analytical and Bioanalytical Chemistry 12/2008; 393(3):969-81. · 3.78 Impact Factor
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ABSTRACT: Benzene and toluene are important industrial chemicals and ubiquitous environmental pollutants. The urinary mercapturic acids of benzene and toluene, S-phenylmercapturic acid (S-PMA) and S-benzylmercapturic acids (S-BMA) are specific biomarkers for the determination of low-level exposures. We have developed and validated a fast, specific and very sensitive method for the simultaneous determination of S-PMA and S-BMA in human urine using an automated multidimensional LC-MS-MS-method that requires no additional sample preparation. Analytes are stripped from urinary matrix by online extraction on a restricted access material, transferred to the analytical column and subsequently determined by tandem mass spectrometry using isotopically labelled S-PMA as internal standard. The lower limit of quantification (LLOQ) for both analytes was 0.05 microg/L urine and sufficient to quantify the background exposure of the general population. Precision within series and between series for S-PMA and S-BMA ranged from 1.0% to 12.2%, accuracy was 108% and 100%, respectively. We applied the method on spot urine samples of 30 subjects of the general population with no known exposure to benzene or toluene. Median levels (range) for S-PMA and S-BMA in non-smokers (n=15) were 0.14 microg/L (<0.05-0.26 microg/L) and 8.2 (1.6-77.4 microg/L), respectively. In smokers (n=15), median levels for S-PMA and S-BMA were 1.22 microg/L (0.17-5.75 microg/L) and 11.5 microg/L (0.9-51.2 microg/L), respectively. Due to its automation, our method is well suited for application in large environmental studies.
Journal of Chromatography B 03/2008; 863(2):283-92. · 2.89 Impact Factor
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ABSTRACT: The analysis of biomarkers from exhaled breath condensate (EBC) is a non-invasive but challenging method for the detection of pulmonary diseases. The amino acids L-proline (Pro) and l-tyrosine (Tyr) are precursors for two important metabolites, trans-L-4-hydroxyproline (trans-L-4-hydroxypyrrolidin-2-carboxylic acid, t-Hyp) and nitrotyrosine (NT). Whereas t-Hyp is supposed to be a biomarker for lung fibrosis, NT is a promising biomarker for inflammation in airway diseases. Analysis of EBC requires extremely sensitive methods, because the epithelial lining fluid of the lung and upper airway is highly diluted in EBC. The high intra- and interindividual variation of this dilution implicates additional problems for sample collection and the interpretation of EBC results. Hence, our aim was to work out a method that would compensate for these possible dilution effects. We have developed a new, reliable and very sensitive method for the simultaneous determination of Pro, t-Hyp, Tyr and NT from EBC. Except for t-Hyp, we used labelled internal standards (IS) L-proline (13)C(5), (15)N (Pro (13)C(5)), L-tyrosine-(13)C(9) (Tyr (13)C(9)), (13)C(9)-3-nitrotyrosine (NT(13)C(9)), IS for t-Hyp was cis-4-hydroxy-L-proline, which were added to the samples before they were lyophilised for concentration. For the separation of the analytes we used hydrophilic interaction liquid chromatography (HILIC), coupled to tandem-mass-spectrometry (MS/MS). The limit of detection (LOD) was 0.5 microg/l for Pro and Tyr and 5 ng/l for t-Hyp and NT. The relative standard deviation (RSD) of the precision from day to day was between 2.6 and 8.0% at spiked concentrations between 4 and 25 microg/l for Pro and between 4.2 and 7.3% for Tyr. The RSD of the precision from day to day was between 7.5 and 13.2% at spiked concentrations between 40 and 250 ng/l for t-Hyp and between 3.5 and 8.2% for NT. The method was established using 27 healthy subjects with a median age of 46 years. Concentrations ranged from 2.8 to 51.9 microg/l for Pro, from <5 to 516.5 ng/l for t-Hyp, from 2.4 to 99.1 for Tyr and for NT concentration ranged between <5 and 1686.5 ng/l.
Journal of Chromatography B 12/2007; 860(1):78-85. · 2.89 Impact Factor
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ABSTRACT: Analysis of biomarkers in exhaled breath condensate (EBC) is a non-invasive method for investigating the effects of different diseases or exposures, on the lungs and airways. N(epsilon)-carboxymethyllysine (CML) is an important biomarker of advanced glycation end products (AGEs). A method has been developed for simultaneous determination of CML and its precursor, the amino acid lysine, in exhaled breath condensate (EBC). After addition of labelled internal standards (d-4-CML; d-4-lysine), the EBC was concentrated by freeze-drying. Separation and detection of the analytes were performed by hydrophilic-ion liquid chromatography coupled with tandem mass-spectrometric detection (HILIC-MS-MS). The limits of quantification were 10 pg mL(-1) EBC and 0.5 ng mL(-1) EBC for CML and lysine, respectively. The relative standard deviation of the within-series precision was between 2.8 and 7.8% at spiked concentrations between 40 and 200 pg mL(-1) for CML and between 6 and 20 ng mL(-1) for lysine. Accuracy for the analytes ranged between 89.5 and 133%. The method was used for the analysis of EBC samples from ten healthy persons from the general population and ten persons receiving dialysis. CML and lysine were detected in all EBC samples with median values of 19 pg mL(-1) CML and 11.9 ng mL(-1) lysine in EBC of healthy persons and 25 pg mL(-1) CML and 9.5 ng mL(-1) lysine in EBC of dialysis patients.
Analytical and Bioanalytical Chemistry 05/2007; 387(8):2783-91. · 3.78 Impact Factor
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The International journal of artificial organs 09/2004; 27(8):728-30. · 1.86 Impact Factor
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ABSTRACT: Acrylamide (AA) (CAS No 79-06-1) has most recently been identified as a food-borne toxicant generated during the heating process of starch-containing foods. It was the aim of the present study to investigate the trans-placental exposure of newborn infants to this possible human carcinogen by analysis of the specific haemoglobin adduct of AA ( N-2-carbamoylethylvaline, AAV) in the blood of mothers and the corresponding umbilical cord blood of neonates as a parameter of biochemical effects.
We investigated the blood of 11 women advanced in pregnancy (one smoker, ten non-smokers) and the corresponding umbilical cord blood of neonates for the N-terminal haemoglobin adducts of AA (AAV) and the smoking-specific adduct of acrylonitrile (CAS No 107-13-1) ( N-cyanoethylvaline, CEV). The limit of detection (LOD) was 5 pmol/g globin for AAV and 4 pmol/g globin for CEV.
AAV could be determined in all blood samples of the mothers (median 21 pmol/g globin, range 18-104 pmol/g globin) as well as in the umbilical cord blood of neonates (median 10 pmol/g globin, range 6-43 pmol/g globin). The highest values were detected in the blood of the smoking mother and her child. CEV was detected only in the blood of the smoking mother (185 pmol/g globin) and the corresponding umbilical cord blood (69 pmol/g globin).
AAV adduct levels in non-smoking mothers and neonates showed a good correlation (r=0.859). The concentration of AA adducts in the blood of neonates is approximately 50% of the adduct level found in the blood of the mother. In view of the shorter life span of neonatal erythrocytes and the lower body weight of newborn infants, the relative internal dose of AA in neonates (in microgrammes per kilogramme body weight) must be assumed to be at least equal to that of the mother. Because of the high cell-replication rates during foetal development, trans-placental exposure of neonates to AA might raise concerns. Neonates of smoking mothers take up much higher doses of AA than those of non-smoking mothers.
Archiv für Gewerbepathologie und Gewerbehygiene 05/2004; 77(3):213-6. · 1.89 Impact Factor
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ABSTRACT: In a chemical plant, alkylating agents (mainly ethylene oxide and propylene oxide, but also dimethyl sulphate) are utilised for the production of special surfactants.
To determine possible uptakes of dimethyl sulphate by workers using N-methylvaline.
Sixty two workers in a chemical plant (38 smokers, 24 non-smokers) with potential exposure to dimethyl sulphate were monitored with respect to their blood levels of N-methylvaline. Ten laboratory workers without exposure to methylating agents were controls. Blood samples of eight workers from a specific working area were analysed for N-methylvaline in a follow up investigation four months later.
The 95th centile for N-methylvaline was 80.7 microg/l blood in the exposed workers compared to 12.4 microg/l blood in controls. In a hot spot area, 10 workers exceeded the German exposure equivalent value for dimethyl sulphate (40 microg/l blood) up to fourfold. In contrast, dimethyl sulphate has not been detectable in workplace air in this area. In a follow up investigation of eight of these 10 workers, N-methylvaline levels were significantly lower, but still increased.
The present study is to our knowledge the first to report increased N-methylvaline levels after occupational exposure to dimethyl sulphate. As ambient monitoring values in the plant could not explain this exposure, skin contact was considered to be the main route of uptake for this substance. Dimethyl sulphate may therefore represent an occupational problem that has been generally underestimated in the past.
Occupational and environmental medicine 02/2004; 61(1):73-5. · 3.64 Impact Factor
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ABSTRACT: We have developed and validated a new, reliable and very sensitive method for the determination of the urinary metabolites of the most common pyrethroids in one analytical run. After acidic hydrolysis for the cleavage of conjugates, the analytes cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-Cl(2)CA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-Cl(2)CA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (Br(2)CA), 4-fluoro-3-phenoxybenzoic acid (F-PBA) and 3-phenoxybenzoic acid (3-PBA) were extracted from the matrix with a liquid-liquid extraction procedure using n-hexane under acidic conditions. For further clean-up, NaOH was added to the organic phase and the carboxylic acids were re-extracted into the aqueous phase. After acidification and extraction into n-hexane again, the metabolites were then derivatised to volatile esters using N-tert.-butyldimethylsilyl-N-methyltrifluoroacetamid (MTBSTFA). Separation and detection were carried out using capillary gas chromatography with mass-selective detection (GC-MS). 2-Phenoxybenzoic acid (2-PBA) served as internal standard for the quantification of the pyrethroid metabolites. The limit of detection for all analytes was 0.05 microg/l urine. The RSD of the within-series imprecision was between 2.0 and 5.4% at a spiked concentration of 0.4 microg/l and the relative recovery was between 79.3 and 93.4%, depending on the analyte. This method was used for the analysis of urine samples of 46 persons from the general population without known exposure to pyrethroids. The metabolites cis-Cl(2)CA, trans-Cl(2)CA and 3-PBA could be found in 52, 72 and 70% of all samples with median values of 0.06, 0.11 and 0.16 microg/l, respectively. Br(2)CA and F-PBA could also be detected in 13 and 4% of the urine samples.
Journal of Chromatography B 11/2002; 778(1-2):121-30. · 2.89 Impact Factor
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ABSTRACT: Phenmedipham [methyl-3-(3-methylphenylcarbamoyloxy)carbamate] is used as a herbicide, especially in the growing of sugar beet and strawberries. During metabolism of the substance in rats, the two carbamate moieties of phenmedipham are cleaved and the metabolites methyl-N-(3-hydroxyphenyl)-carbamate, m-aminophenol and hydroxyacetanilide are formed. These compounds and their conjugates are excreted in urine. Additionally, it has been suggested that m-toluidine is formed during metabolism. For the first time it has been possible to detect this metabolite in the urine of workers after agricultural use of phenmedipham. The concentrations of m-toluidine in urine were significantly higher in persons occupationally exposed than in controls. The median values for each group were 0.36 microg/l and 0.16 microg/l, respectively. This means that persons not exposed to phenmedipham also excrete m-toluidine, possibly as a result of the uptake of pesticides like phenmedipham from the diet.
Archive für Toxikologie 06/2001; 75(3):145-9. · 4.67 Impact Factor
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ABSTRACT: We have developed and validated a new, reliable and very sensitive method for the determination of the urinary metabolites of the most common pyrethroids in one analytical run. After acidic hydrolysis for the cleavage of conjugates, the analytes cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-Cl2CA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-Cl2CA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (Br2CA), 4-fluoro-3-phenoxybenzoic acid (F-PBA) and 3-phenoxybenzoic acid (3-PBA) were extracted from the matrix with a liquid–liquid extraction procedure using n-hexane under acidic conditions. For further clean-up, NaOH was added to the organic phase and the carboxylic acids were re-extracted into the aqueous phase. After acidification and extraction into n-hexane again, the metabolites were then derivatised to volatile esters using N-tert.-butyldimethylsilyl-N-methyltrifluoroacetamid (MTBSTFA). Separation and detection were carried out using capillary gas chromatography with mass-selective detection (GC–MS). 2-Phenoxybenzoic acid (2-PBA) served as internal standard for the quantification of the pyrethroid metabolites. The limit of detection for all analytes was 0.05 μg/l urine. The RSD of the within-series imprecision was between 2.0 and 5.4% at a spiked concentration of 0.4 μg/l and the relative recovery was between 79.3 and 93.4%, depending on the analyte. This method was used for the analysis of urine samples of 46 persons from the general population without known exposure to pyrethroids. The metabolites cis-Cl2CA, trans-Cl2CA and 3-PBA could be found in 52, 72 and 70% of all samples with median values of 0.06, 0.11 and 0.16 μg/l, respectively. Br2CA and F-PBA could also be detected in 13 and 4% of the urine samples.
Journal of Chromatography B.
