The Experts below are selected from a list of 11901 Experts worldwide ranked by ideXlab platform
Christian H Lindh - One of the best experts on this subject based on the ideXlab platform.
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analysis of ethylenethiourea as a biomarker in human Urine using liquid chromatography triple quadrupole mass spectrometry
Rapid Communications in Mass Spectrometry, 2008Co-Authors: Christian H Lindh, Margareta Littorin, Gunvor Johannesson, Bo JonssonAbstract:Ethylenebisdithiocarbamates (EBDCs) are widely used fungicides. Ethylenethiourea (ETU), the main metabolite and also a contaminant in the commercially available products, is of major toxicological concern. In this study, a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) is described for the analysis of ETU in human Urine after a single-step extractive derivatization using pentafluorobenzyl bromide (PFBBr). Analysis was carried out using selected reaction monitoring (SRM) in the positive ion mode. Quantification of ETU was performed using [(2)H(4)]-labeled ETU as internal standard (IS). The limit of detection (LOD) was determined to 0.05 ng/mL. The method was linear in the range 0.1-54 ng/mL Urine and had a within-run precision of 3-5%. The between-run precision was determined at an average Urine level of 2 and 10 ng/mL Urine and found to be 9%. The inter-batch precision was 6%. To validate ETU as a biomarker of exposure, the method was applied in a human experimental oral exposure to the commercial fungicide Ridomil Gold, containing 64% mancozeb and 4.5% ETU. Two healthy volunteers received 8.9 microg/kg body weight (b.w.) Ridomil Gold in a single oral dose followed by Urine Sampling for 104 h post-exposure. The elimination half-life of ETU was estimated to 17-23 h.
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analysis of 3 5 dichloroaniline as a biomarker of vinclozolin and iprodione in human Urine using liquid chromatography triple quadrupole mass spectrometry
Rapid Communications in Mass Spectrometry, 2007Co-Authors: Christian H Lindh, Margareta Littorin, Asa Amilon, Bo A G JonssonAbstract:The fungicides vinclozolin and iprodione are widely used in agriculture. These pesticides are dicarboximide fungicides containing the common moiety 3,5-dichloroaniline (3,5-DCA). It has been suggested that low-level exposures to such compounds may be associated with adverse health effects such as endocrine disruption. In this study a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) was developed for the analysis of 3,5-DCA as a biomarker of exposure to these fungicides in human Urine. The Urine samples were treated by basic hydrolysis to degrade the fungicides, their metabolites and conjugates to 3,5-DCA. The 3,5-DCA was then extracted using toluene and derivatized using pentafluoropropionic anhydride (PFPA). Analysis of the derivative was carried out using selected reaction monitoring (SRM) in the negative ion mode. Quantification of the derivative was performed using [(13)C(6)]-labeled 3,4-DCA as an internal standard with good precision and linearity in the range 0.1-200 ng/mL Urine. The limit of detection was determined to be 0.1 ng/mL. The metabolites in Urine were found to be stable during storage at -20 degrees C. To validate 3,5-DCA as a biomarker the method was applied in a human experimental exposure to iprodione and vinclozolin. Two healthy volunteers received 200 microg single oral doses of each pesticide followed by Urine Sampling during 72-120 h post-exposure. Between 78-107% of the dose was recovered as 3,5-DCA in the Urine after exposure.
Des Connell - One of the best experts on this subject based on the ideXlab platform.
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comparative evaluation of chlorpyrifos exposure estimates from whole body dermal dosimetry and urinary trichloro 2 pyridinol tcp methods
Ecotoxicology and Environmental Safety, 2019Co-Authors: Albert Atabila, Dung Tri Phung, R Sadler, Des ConnellAbstract:Abstract Chlorpyrifos is one of the most widely used organophosphate pesticides and has a record of adverse effects on applicators. Assessment of exposure to chlorpyrifos based on its urinary metabolite, 3,5,6-trichloro-2-pyridinol (TCP), is considered as the most accurate. However, Urine Sampling can be difficult, and the laboratory analytical procedures involved are complex and expensive. A simpler approach for assessing pesticide exposure among applicators is the whole-body dermal dosimetry method, but this needs validation. The objective of this study was to compare chlorpyrifos exposure estimates obtained separately with the urinary TCP and the whole-body dermal dosimetry methods from applicators. Exposure estimates from the whole-body dermal dosimetry method (5–29 μg/kg/day) showed less variation than those from the urinary TCP method (1–71 μg/kg/day), but both were in close agreement at the mean level (16 μg/kg/day and 15 μg/kg/day, respectively). The whole-body dermal dosimetry method is therefore valid for providing estimates of the typical levels of pesticide exposure among applicators in situations where the urinary TCP method cannot be applied.
Margareta Littorin - One of the best experts on this subject based on the ideXlab platform.
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analysis of ethylenethiourea as a biomarker in human Urine using liquid chromatography triple quadrupole mass spectrometry
Rapid Communications in Mass Spectrometry, 2008Co-Authors: Christian H Lindh, Margareta Littorin, Gunvor Johannesson, Bo JonssonAbstract:Ethylenebisdithiocarbamates (EBDCs) are widely used fungicides. Ethylenethiourea (ETU), the main metabolite and also a contaminant in the commercially available products, is of major toxicological concern. In this study, a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) is described for the analysis of ETU in human Urine after a single-step extractive derivatization using pentafluorobenzyl bromide (PFBBr). Analysis was carried out using selected reaction monitoring (SRM) in the positive ion mode. Quantification of ETU was performed using [(2)H(4)]-labeled ETU as internal standard (IS). The limit of detection (LOD) was determined to 0.05 ng/mL. The method was linear in the range 0.1-54 ng/mL Urine and had a within-run precision of 3-5%. The between-run precision was determined at an average Urine level of 2 and 10 ng/mL Urine and found to be 9%. The inter-batch precision was 6%. To validate ETU as a biomarker of exposure, the method was applied in a human experimental oral exposure to the commercial fungicide Ridomil Gold, containing 64% mancozeb and 4.5% ETU. Two healthy volunteers received 8.9 microg/kg body weight (b.w.) Ridomil Gold in a single oral dose followed by Urine Sampling for 104 h post-exposure. The elimination half-life of ETU was estimated to 17-23 h.
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analysis of 3 5 dichloroaniline as a biomarker of vinclozolin and iprodione in human Urine using liquid chromatography triple quadrupole mass spectrometry
Rapid Communications in Mass Spectrometry, 2007Co-Authors: Christian H Lindh, Margareta Littorin, Asa Amilon, Bo A G JonssonAbstract:The fungicides vinclozolin and iprodione are widely used in agriculture. These pesticides are dicarboximide fungicides containing the common moiety 3,5-dichloroaniline (3,5-DCA). It has been suggested that low-level exposures to such compounds may be associated with adverse health effects such as endocrine disruption. In this study a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) was developed for the analysis of 3,5-DCA as a biomarker of exposure to these fungicides in human Urine. The Urine samples were treated by basic hydrolysis to degrade the fungicides, their metabolites and conjugates to 3,5-DCA. The 3,5-DCA was then extracted using toluene and derivatized using pentafluoropropionic anhydride (PFPA). Analysis of the derivative was carried out using selected reaction monitoring (SRM) in the negative ion mode. Quantification of the derivative was performed using [(13)C(6)]-labeled 3,4-DCA as an internal standard with good precision and linearity in the range 0.1-200 ng/mL Urine. The limit of detection was determined to be 0.1 ng/mL. The metabolites in Urine were found to be stable during storage at -20 degrees C. To validate 3,5-DCA as a biomarker the method was applied in a human experimental exposure to iprodione and vinclozolin. Two healthy volunteers received 200 microg single oral doses of each pesticide followed by Urine Sampling during 72-120 h post-exposure. Between 78-107% of the dose was recovered as 3,5-DCA in the Urine after exposure.
Bo A G Jonsson - One of the best experts on this subject based on the ideXlab platform.
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analysis of 3 5 dichloroaniline as a biomarker of vinclozolin and iprodione in human Urine using liquid chromatography triple quadrupole mass spectrometry
Rapid Communications in Mass Spectrometry, 2007Co-Authors: Christian H Lindh, Margareta Littorin, Asa Amilon, Bo A G JonssonAbstract:The fungicides vinclozolin and iprodione are widely used in agriculture. These pesticides are dicarboximide fungicides containing the common moiety 3,5-dichloroaniline (3,5-DCA). It has been suggested that low-level exposures to such compounds may be associated with adverse health effects such as endocrine disruption. In this study a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) was developed for the analysis of 3,5-DCA as a biomarker of exposure to these fungicides in human Urine. The Urine samples were treated by basic hydrolysis to degrade the fungicides, their metabolites and conjugates to 3,5-DCA. The 3,5-DCA was then extracted using toluene and derivatized using pentafluoropropionic anhydride (PFPA). Analysis of the derivative was carried out using selected reaction monitoring (SRM) in the negative ion mode. Quantification of the derivative was performed using [(13)C(6)]-labeled 3,4-DCA as an internal standard with good precision and linearity in the range 0.1-200 ng/mL Urine. The limit of detection was determined to be 0.1 ng/mL. The metabolites in Urine were found to be stable during storage at -20 degrees C. To validate 3,5-DCA as a biomarker the method was applied in a human experimental exposure to iprodione and vinclozolin. Two healthy volunteers received 200 microg single oral doses of each pesticide followed by Urine Sampling during 72-120 h post-exposure. Between 78-107% of the dose was recovered as 3,5-DCA in the Urine after exposure.
Bo Jonsson - One of the best experts on this subject based on the ideXlab platform.
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analysis of ethylenethiourea as a biomarker in human Urine using liquid chromatography triple quadrupole mass spectrometry
Rapid Communications in Mass Spectrometry, 2008Co-Authors: Christian H Lindh, Margareta Littorin, Gunvor Johannesson, Bo JonssonAbstract:Ethylenebisdithiocarbamates (EBDCs) are widely used fungicides. Ethylenethiourea (ETU), the main metabolite and also a contaminant in the commercially available products, is of major toxicological concern. In this study, a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) is described for the analysis of ETU in human Urine after a single-step extractive derivatization using pentafluorobenzyl bromide (PFBBr). Analysis was carried out using selected reaction monitoring (SRM) in the positive ion mode. Quantification of ETU was performed using [(2)H(4)]-labeled ETU as internal standard (IS). The limit of detection (LOD) was determined to 0.05 ng/mL. The method was linear in the range 0.1-54 ng/mL Urine and had a within-run precision of 3-5%. The between-run precision was determined at an average Urine level of 2 and 10 ng/mL Urine and found to be 9%. The inter-batch precision was 6%. To validate ETU as a biomarker of exposure, the method was applied in a human experimental oral exposure to the commercial fungicide Ridomil Gold, containing 64% mancozeb and 4.5% ETU. Two healthy volunteers received 8.9 microg/kg body weight (b.w.) Ridomil Gold in a single oral dose followed by Urine Sampling for 104 h post-exposure. The elimination half-life of ETU was estimated to 17-23 h.
