The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Aurélie Berthet - One of the best experts on this subject based on the ideXlab platform.
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A Detailed Urinary Excretion Time Course Study of Captan and Folpet Biomarkers in Workers for the Estimation of Dose, Main Route-of-Entry and Most Appropriate Sampling and Analysis Strategies
The Annals of occupational hygiene, 2012Co-Authors: Aurélie Berthet, Roberto Heredia-ortiz, Brigitta Danuser, David Vernez, Michèle BouchardAbstract:Captan and Folpet are two fungicides largely used in agriculture, but biomonitoring data are mostly limited to measurements of captan metabolite concentrations in spot urine samples of workers, which complicate interpretation of results in terms of internal dose estimation, daily variations according to tasks performed, and most plausible routes of exposure. This study aimed at performing repeated biological measurements of exposure to captan and Folpet in field workers (i) to better assess internal dose along with main routes-of-entry according to tasks and (ii) to establish most appropriate sampling and analysis strategies. The detailed urinary excretion time courses of specific and non-specific biomarkers of exposure to captan and Folpet were established in tree farmers (n 5 2) and grape growers (n 5 3) over a typical workweek (seven consecutive days), including spraying and harvest activities. The impact of the expression of urinary measurements [excretion rate values adjusted or not for creatinine or cumulative amounts over given time periods (8, 12, and 24 h)] was evaluated. Absorbed doses and main routes-of-entry were then estimated from the 24-h cumulative urinary amounts through the use of a kinetic model. The time courses showed that exposure levels were higher during spraying than harvest activities. Model simulations also suggest a limited absorption in the studied workers and an exposure mostly through the dermal route. It further pointed out the advantage of expressing biomarker values in terms of body weight-adjusted amounts in repeated 24-h urine collections as compared to concentrations or excretion rates in spot samples, without the necessity for creatinine corrections.
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toxicokinetics of captan and Folpet biomarkers in orally exposed volunteers
Journal of Applied Toxicology, 2012Co-Authors: Aurélie Berthet, Michèle Bouchard, Brigitta DanuserAbstract:The time courses of key biomarkers of exposure to captan and Folpet was assessed in accessible biological matrices of orally exposed volunteers. Ten volunteers ingested 1 mg kg(-1) body weight of captan or Folpet. Blood samples were withdrawn at fixed time periods over the 72 h following ingestion and complete urine voids were collected over 96 h post-dosing. The tetrahydrophthalimide (THPI) metabolite of captan along with the phthalimide (PI) and phthalic acid metabolites of Folpet were then quantified in these samples. Plasma levels of THPI and PI increased progressively after ingestion, reaching peak values ~10 and 6 h post-dosing, respectively; subsequent elimination phase appeared monophasic with a mean elimination half-life (t(½) ) of 15.7 and 31.5 h, respectively. In urine, elimination rate time courses of PI and phthalic acid evolved in parallel, with respective t(½) of 27.3 and 27.6 h; relatively faster elimination was found for THPI, with mean t(½) of 11.7 h. However, phthalic acid was present in urine in 1000-fold higher amounts than PI. In the 96 h period post-treatment, on average 25% of Folpet dose was excreted in urine as phthalic acid as compared with only 0.02% as PI. The corresponding value for THPI was 3.5%. Overall, THPI and PI appear as interesting biomarkers of recent exposure, with relatively short half-lives; their sensitivity to assess exposure in field studies should be further verified. Although not a metabolite specific to Folpet, the concomitant use of phthalic acid as a major biomarker of exposure to Folpet should also be considered.
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Toxicokinetic modeling of Folpet fungicide and its ring-biomarkers of exposure in humans.
Journal of applied toxicology : JAT, 2011Co-Authors: Roberto Heredia-ortiz, Aurélie Berthet, Michèle BouchardAbstract:A human in vivo toxicokinetic model was built to allow a better understanding of the toxicokinetics of Folpet fungicide and its key ring biomarkers of exposure: phthalimide (PI), phthalamic acid (PAA) and phthalic acid (PA). Both PI and the sum of ring metabolites, expressed as PA equivalents (PAeq), may be used as biomarkers of exposure. The conceptual representation of the model was based on the analysis of the time course of these biomarkers in volunteers orally and dermally exposed to Folpet. In the model, compartments were also used to represent the body burden of Folpet and experimentally relevant PI, PAA and PA ring metabolites in blood and in key tissues as well as in excreta, hence urinary and feces. The time evolution of these biomarkers in each compartment of the model was then mathematically described by a system of coupled differential equations. The mathematical parameters of the model were then determined from best fits to the time courses of PI and PAeq in blood and urine of five volunteers administered orally 1 mg kg(-1) and dermally 10 mg kg(-1) of Folpet. In the case of oral administration, the mean elimination half-life of PI from blood (through feces, urine or metabolism) was found to be 39.9 h as compared with 28.0 h for PAeq. In the case of a dermal application, mean elimination half-life of PI and PAeq was estimated to be 34.3 and 29.3 h, respectively. The average final fractions of administered dose recovered in urine as PI over the 0-96 h period were 0.030 and 0.002%, for oral and dermal exposure, respectively. Corresponding values for PAeq were 24.5 and 1.83%, respectively. Finally, the average clearance rate of PI from blood calculated from the oral and dermal data was 0.09 ± 0.03 and 0.13 ± 0.05 ml h(-1) while the volume of distribution was 4.30 ± 1.12 and 6.05 ± 2.22 l, respectively. It was not possible to obtain the corresponding values from PAeq data owing to the lack of blood time course data.
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Gas-chromatography mass-spectrometry determination of phthalic acid in human urine as a biomarker of Folpet exposure.
Analytical and bioanalytical chemistry, 2011Co-Authors: Aurélie Berthet, Michèle Berode, Michèle BouchardAbstract:Agricultural workers are exposed to Folpet, but biomonitoring data are limited. Phthalimide (PI), phthala- mic acid (PAA), and phthalic acid (PA) are the ring metabolites of this fungicide according to animal studies, but they have not yet been measured in human urine as metabolites of Folpet, only PA as a metabolite of phthalates. The objective of this study was thus to develop a reliable gas chromatography-tandem mass spectrometry (GC-MS) method to quantify the sum of PI, PAA, and PA ring- metabolites of Folpet in human urine. Briefly, the method consisted of adding p-methylhippuric acid as an internal standard, performing an acid hydrolysis at 100 °C to convert ring-metabolites into PA, purifying samples by ethyl acetate extraction, and derivatizing with N,O-bis (trimethylsilyl)trifluoro acetamide prior to GC-MS analy- sis. The method had a detection limit of 60.2 nmol/L (10 ng/mL); it was found to be accurate (mean recovery, 97%), precise (inter- and intra-day percentage relative standard deviations 0.98). Validation was conducted using unexposed peoples urine spiked at concentrations ranging from 4.0 to 16.1 μmol/L, along with urine samples of volunteers dosed with Folpet, and of exposed workers. The method proved to be (1) suitable and accurate to determine the kinetic profile of PA equivalents in the urine of volunteers orally and dermally administered Folpet and (2) relevant for the biomonitoring of exposure in workers.
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liquid chromatography tandem mass spectrometry lc apci ms ms methods for the quantification of captan and Folpet phthalimide metabolites in human plasma and urine
Analytical and Bioanalytical Chemistry, 2011Co-Authors: Aurélie Berthet, Michèle Bouchard, Brigitta Danuser, Patrick Schupfer, David Vernez, Cong Khanh HuynhAbstract:Captan and Folpet are fungicides largely used in agriculture. They have similar chemical structures, except that Folpet has an aromatic ring unlike captan. Their half- lives in blood are very short, given that they are readily broken down to tetrahydrophthalimide (THPI) and phtha- limide (PI), respectively. Few authors measured these biomarkers in plasma or urine, and analysis was conducted either by gas chromatography coupled to mass spectrome- try or liquid chromatography with UV detection. The objective of this study was thus to develop simple, sensitive and specific liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC/APCI- MS/MS) methods to quantify both THPI and PI in human plasma and urine. Briefly, deuterated THPI was added as an internal standard and purification was performed by solid- phase extraction followed by LC/APCI-MS/MS analysis in negative ion mode for both compounds. Validation of the methods was conducted using spiked blank plasma and urine samples at concentrations ranging from 1 to 250 μg/L and 1 to 50 μg/L, respectively, along with samples of volunteers and workers exposed to captan or Folpet. The methods showed a good linearity (R 2 >0.99), recovery (on average 90% for THPI and 75% for PI), intra- and inter-day precision (RSD, <15%) and accuracy (<20%), and stability. The limit of detection was 0.58 μg/L in urine and 1.47 μg/L in plasma for THPI and 1.14 and 2.17 μg/L, respectively, for PI. The described methods proved to be accurate and suitable to determine the toxicokinetics of both metabolites in human plasma and urine.
Michèle Bouchard - One of the best experts on this subject based on the ideXlab platform.
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A Detailed Urinary Excretion Time Course Study of Captan and Folpet Biomarkers in Workers for the Estimation of Dose, Main Route-of-Entry and Most Appropriate Sampling and Analysis Strategies
The Annals of occupational hygiene, 2012Co-Authors: Aurélie Berthet, Roberto Heredia-ortiz, Brigitta Danuser, David Vernez, Michèle BouchardAbstract:Captan and Folpet are two fungicides largely used in agriculture, but biomonitoring data are mostly limited to measurements of captan metabolite concentrations in spot urine samples of workers, which complicate interpretation of results in terms of internal dose estimation, daily variations according to tasks performed, and most plausible routes of exposure. This study aimed at performing repeated biological measurements of exposure to captan and Folpet in field workers (i) to better assess internal dose along with main routes-of-entry according to tasks and (ii) to establish most appropriate sampling and analysis strategies. The detailed urinary excretion time courses of specific and non-specific biomarkers of exposure to captan and Folpet were established in tree farmers (n 5 2) and grape growers (n 5 3) over a typical workweek (seven consecutive days), including spraying and harvest activities. The impact of the expression of urinary measurements [excretion rate values adjusted or not for creatinine or cumulative amounts over given time periods (8, 12, and 24 h)] was evaluated. Absorbed doses and main routes-of-entry were then estimated from the 24-h cumulative urinary amounts through the use of a kinetic model. The time courses showed that exposure levels were higher during spraying than harvest activities. Model simulations also suggest a limited absorption in the studied workers and an exposure mostly through the dermal route. It further pointed out the advantage of expressing biomarker values in terms of body weight-adjusted amounts in repeated 24-h urine collections as compared to concentrations or excretion rates in spot samples, without the necessity for creatinine corrections.
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toxicokinetics of captan and Folpet biomarkers in orally exposed volunteers
Journal of Applied Toxicology, 2012Co-Authors: Aurélie Berthet, Michèle Bouchard, Brigitta DanuserAbstract:The time courses of key biomarkers of exposure to captan and Folpet was assessed in accessible biological matrices of orally exposed volunteers. Ten volunteers ingested 1 mg kg(-1) body weight of captan or Folpet. Blood samples were withdrawn at fixed time periods over the 72 h following ingestion and complete urine voids were collected over 96 h post-dosing. The tetrahydrophthalimide (THPI) metabolite of captan along with the phthalimide (PI) and phthalic acid metabolites of Folpet were then quantified in these samples. Plasma levels of THPI and PI increased progressively after ingestion, reaching peak values ~10 and 6 h post-dosing, respectively; subsequent elimination phase appeared monophasic with a mean elimination half-life (t(½) ) of 15.7 and 31.5 h, respectively. In urine, elimination rate time courses of PI and phthalic acid evolved in parallel, with respective t(½) of 27.3 and 27.6 h; relatively faster elimination was found for THPI, with mean t(½) of 11.7 h. However, phthalic acid was present in urine in 1000-fold higher amounts than PI. In the 96 h period post-treatment, on average 25% of Folpet dose was excreted in urine as phthalic acid as compared with only 0.02% as PI. The corresponding value for THPI was 3.5%. Overall, THPI and PI appear as interesting biomarkers of recent exposure, with relatively short half-lives; their sensitivity to assess exposure in field studies should be further verified. Although not a metabolite specific to Folpet, the concomitant use of phthalic acid as a major biomarker of exposure to Folpet should also be considered.
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Toxicokinetic modeling of Folpet fungicide and its ring-biomarkers of exposure in humans.
Journal of applied toxicology : JAT, 2011Co-Authors: Roberto Heredia-ortiz, Aurélie Berthet, Michèle BouchardAbstract:A human in vivo toxicokinetic model was built to allow a better understanding of the toxicokinetics of Folpet fungicide and its key ring biomarkers of exposure: phthalimide (PI), phthalamic acid (PAA) and phthalic acid (PA). Both PI and the sum of ring metabolites, expressed as PA equivalents (PAeq), may be used as biomarkers of exposure. The conceptual representation of the model was based on the analysis of the time course of these biomarkers in volunteers orally and dermally exposed to Folpet. In the model, compartments were also used to represent the body burden of Folpet and experimentally relevant PI, PAA and PA ring metabolites in blood and in key tissues as well as in excreta, hence urinary and feces. The time evolution of these biomarkers in each compartment of the model was then mathematically described by a system of coupled differential equations. The mathematical parameters of the model were then determined from best fits to the time courses of PI and PAeq in blood and urine of five volunteers administered orally 1 mg kg(-1) and dermally 10 mg kg(-1) of Folpet. In the case of oral administration, the mean elimination half-life of PI from blood (through feces, urine or metabolism) was found to be 39.9 h as compared with 28.0 h for PAeq. In the case of a dermal application, mean elimination half-life of PI and PAeq was estimated to be 34.3 and 29.3 h, respectively. The average final fractions of administered dose recovered in urine as PI over the 0-96 h period were 0.030 and 0.002%, for oral and dermal exposure, respectively. Corresponding values for PAeq were 24.5 and 1.83%, respectively. Finally, the average clearance rate of PI from blood calculated from the oral and dermal data was 0.09 ± 0.03 and 0.13 ± 0.05 ml h(-1) while the volume of distribution was 4.30 ± 1.12 and 6.05 ± 2.22 l, respectively. It was not possible to obtain the corresponding values from PAeq data owing to the lack of blood time course data.
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Gas-chromatography mass-spectrometry determination of phthalic acid in human urine as a biomarker of Folpet exposure.
Analytical and bioanalytical chemistry, 2011Co-Authors: Aurélie Berthet, Michèle Berode, Michèle BouchardAbstract:Agricultural workers are exposed to Folpet, but biomonitoring data are limited. Phthalimide (PI), phthala- mic acid (PAA), and phthalic acid (PA) are the ring metabolites of this fungicide according to animal studies, but they have not yet been measured in human urine as metabolites of Folpet, only PA as a metabolite of phthalates. The objective of this study was thus to develop a reliable gas chromatography-tandem mass spectrometry (GC-MS) method to quantify the sum of PI, PAA, and PA ring- metabolites of Folpet in human urine. Briefly, the method consisted of adding p-methylhippuric acid as an internal standard, performing an acid hydrolysis at 100 °C to convert ring-metabolites into PA, purifying samples by ethyl acetate extraction, and derivatizing with N,O-bis (trimethylsilyl)trifluoro acetamide prior to GC-MS analy- sis. The method had a detection limit of 60.2 nmol/L (10 ng/mL); it was found to be accurate (mean recovery, 97%), precise (inter- and intra-day percentage relative standard deviations 0.98). Validation was conducted using unexposed peoples urine spiked at concentrations ranging from 4.0 to 16.1 μmol/L, along with urine samples of volunteers dosed with Folpet, and of exposed workers. The method proved to be (1) suitable and accurate to determine the kinetic profile of PA equivalents in the urine of volunteers orally and dermally administered Folpet and (2) relevant for the biomonitoring of exposure in workers.
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liquid chromatography tandem mass spectrometry lc apci ms ms methods for the quantification of captan and Folpet phthalimide metabolites in human plasma and urine
Analytical and Bioanalytical Chemistry, 2011Co-Authors: Aurélie Berthet, Michèle Bouchard, Brigitta Danuser, Patrick Schupfer, David Vernez, Cong Khanh HuynhAbstract:Captan and Folpet are fungicides largely used in agriculture. They have similar chemical structures, except that Folpet has an aromatic ring unlike captan. Their half- lives in blood are very short, given that they are readily broken down to tetrahydrophthalimide (THPI) and phtha- limide (PI), respectively. Few authors measured these biomarkers in plasma or urine, and analysis was conducted either by gas chromatography coupled to mass spectrome- try or liquid chromatography with UV detection. The objective of this study was thus to develop simple, sensitive and specific liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC/APCI- MS/MS) methods to quantify both THPI and PI in human plasma and urine. Briefly, deuterated THPI was added as an internal standard and purification was performed by solid- phase extraction followed by LC/APCI-MS/MS analysis in negative ion mode for both compounds. Validation of the methods was conducted using spiked blank plasma and urine samples at concentrations ranging from 1 to 250 μg/L and 1 to 50 μg/L, respectively, along with samples of volunteers and workers exposed to captan or Folpet. The methods showed a good linearity (R 2 >0.99), recovery (on average 90% for THPI and 75% for PI), intra- and inter-day precision (RSD, <15%) and accuracy (<20%), and stability. The limit of detection was 0.58 μg/L in urine and 1.47 μg/L in plasma for THPI and 1.14 and 2.17 μg/L, respectively, for PI. The described methods proved to be accurate and suitable to determine the toxicokinetics of both metabolites in human plasma and urine.
Flavia Badoud - One of the best experts on this subject based on the ideXlab platform.
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quantification of Folpet and phthalimide in tea and herbal infusions by lc high resolution ms and gc ms ms
Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment, 2019Co-Authors: Jose Fernando Huertasperez, Marion Ernest, Flavia BadoudAbstract:Two methods based on a modified QuEChERS sample preparation and either LC coupled to atmospheric pressure ionisation and high-resolution MS or GC coupled to electron ionisation and tripled quadrupole MS have been assessed for the quantification of Folpet and phthalimide in tea and other dry herbal infusions. Both methods have been fully validated in green tea and further checked in black tea, verbena and rooibos, and they performed according to the SANTE/11813/2017 criteria at the target LOQ concentration level (50 µg/kg). These methods allow the accurate quantification of Folpet in the selected matrices according to the new EU residue definition, which includes phthalimide. Phthalimide is the main metabolite and degradation product of Folpet, although according to recent studies, it could be generated from different sources than Folpet breakdown, such as food processing or analysis by GC.
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Quantification of Folpet and phthalimide in tea and herbal infusions by LC– high-resolution MS and GC–MS/MS
2019Co-Authors: José Fernando Huertas-pérez, Marion Ernest, Flavia BadoudAbstract:Two methods based on a modified QuEChERS sample preparation and either LC coupled to atmospheric pressure ionisation and high-resolution MS or GC coupled to electron ionisation and tripled quadrupole MS have been assessed for the quantification of Folpet and phthalimide in tea and other dry herbal infusions. Both methods have been fully validated in green tea and further checked in black tea, verbena and rooibos, and they performed according to the SANTE/11813/2017 criteria at the target LOQ concentration level (50 µg/kg). These methods allow the accurate quantification of Folpet in the selected matrices according to the new EU residue definition, which includes phthalimide. Phthalimide is the main metabolite and degradation product of Folpet, although according to recent studies, it could be generated from different sources than Folpet breakdown, such as food processing or analysis by GC.
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Quantification of Folpet and phthalimide in food by gas chromatography and mass spectrometry: Overcoming potential analytical artefacts.
Food chemistry, 2018Co-Authors: José Fernando Huertas-pérez, Marion Ernest, Jesus Varela, Flavia BadoudAbstract:Abstract Accurate quantification of Folpet is problematic because it degrades into phthalimide during sample preparation and analysis by gas chromatography (GC). Thus, EU regulation was recently modified to include phthalimide in the Folpet residue definition. However, recent studies have shown that phthalimide could also be generated from different sources, which could lead to an overestimation of the phthalimide content and therefore to false positives. GC coupled with either negative chemical ionisation and single quadrupole mass spectrometry, or electron ionisation with triple quadrupole mass spectrometry (GC-EI-MS/MS), were evaluated for the determination of Folpet and phthalimide in food. Both methods were validated in 4 different matrices namely apple puree, rice flour, raspberry puree and infant formula. Better selectivity and precision were obtained with GC-EI-MS/MS. Negligible amounts of phthalimide was found in blank matrices, and validation results met the SANTE/11813/2017 criteria in all matrices at the LOQ concentration levels by using GC-EI-MS/MS.
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Artifact-controlled quantification of Folpet and phthalimide in food by liquid chromatography-high resolution mass spectrometry
Food Control, 2018Co-Authors: Flavia Badoud, Marion Ernest, Yves-alexis Hammel, José Fernando Huertas-pérezAbstract:Abstract The European residue definition for the pesticide Folpet has changed in 2016 to include its degradation product phthalimide. According to recent studies, phthalimide could also arise from other sources than Folpet, including formation in the injector of gas chromatography systems from the precursor phthalic acid or phthalic anhydride. A liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry (MS) method was developed for the quantification of Folpet and phthalimide. High resolution MS was deemed necessary to increase the selectivity via accurate mass, as phthalimide and Folpet yielded poor fragmentation. Sample preparation by QuEChERS was optimized to ensure the stability of Folpet and to prevent the contamination of phthalimide from external sources. The method was validated on four matrices from four commodity groups (i.e., high water content, high water and acid content, high starch content and dairy products). Linearity was assessed with r2 > 0.99 over the range 5–200 μg kg−1, repeatability ranged between 6.8% and 14.5%, intermediate precision between 10% and 23.8%, and trueness was within 78.6% and 124.2% with relative standard deviation from 3% to 20%. These performance parameters were all compliant with the analytical requirements stipulated in the SANTE/11813/2017 document. The method was verified on 12 additional matrices from the 4 commodity groups. The present method was suitable for the quantification of Folpet and phthalimide in foods while controlling analytical artifact.
Wayne Belzer - One of the best experts on this subject based on the ideXlab platform.
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atmospheric concentrations of captan and Folpet in the lower fraser valley agricultural region of canada
Air Soil and Water Research, 2009Co-Authors: Renata Raina, Wayne Belzer, Keith JonesAbstract:Two N-trihalomethylthio fungicides were detected in the atmosphere in the Lower Fraser Valley agricultural region of Canada. Captan was detected in both the particle and gas phase with a dominant particle phase fraction observed in both 2005 and 2006 (only total captan atmospheric concentrations were available for 2004). This provides the first evidence of particle transport as a significant atmospheric transport pathway for captan in an agricultural region in Canada. Weekly captan air concentrations reached maximum levels of 13.2 ng m-3 in June 2006, while for Folpet total atmospheric levels were lower with maximum reaching 1.7 ng m-3 in August 2004 and generally <1 ng m3 in 2005 and 2006. Folpet is detected in the atmosphere although not previously reported in usage inventories. In the three years examined (2004-2006) captan concentrations observed a seasonal maximum in atmospheric concentrations during spring to early summer coinciding with expected peak usage period on crops in the Lower Fraser Valley...
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large volume cold on column injection for gas chromatography negative chemical ionization mass spectrometry analysis of selected pesticides in air samples
Journal of Agricultural and Food Chemistry, 2007Co-Authors: Renata Bailey, Wayne BelzerAbstract:A new gas chromatographic method is described for the analysis of fungicides captan, captafol, and Folpet from organic extracts of air samples using large volume injection (LVI) via a cold on-column (COC) inlet coupled with gas chromatography−negative chemical ionization−mass spectrometry (GC-NCI-MS). Although standard split/splitless injection due to high injection port temperatures (>225 °C) have been shown to degrade these thermally labile fungicides, COC injection minimizes degradation. Insecticides such as chlorpyrifos and diazinon were also examined to show added selectivity. By using a solvent vapor exit with the COC inlet, injection volumes of 10−100 μL can be made to lower detection levels. GC-NCI-MS was compared to GC−electron impact ionization−mass spectrometry for each pesticide using LVI-COC injections and was found to be 2−80 times more sensitive, depending on the pesticide. Method detection limit (MDL) values with 100 μL injections were 2.5 μg L-1 for captan, Folpet, and diazinon, 5.0 μg L-...
José Fernando Huertas-pérez - One of the best experts on this subject based on the ideXlab platform.
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Quantification of Folpet and phthalimide in tea and herbal infusions by LC– high-resolution MS and GC–MS/MS
2019Co-Authors: José Fernando Huertas-pérez, Marion Ernest, Flavia BadoudAbstract:Two methods based on a modified QuEChERS sample preparation and either LC coupled to atmospheric pressure ionisation and high-resolution MS or GC coupled to electron ionisation and tripled quadrupole MS have been assessed for the quantification of Folpet and phthalimide in tea and other dry herbal infusions. Both methods have been fully validated in green tea and further checked in black tea, verbena and rooibos, and they performed according to the SANTE/11813/2017 criteria at the target LOQ concentration level (50 µg/kg). These methods allow the accurate quantification of Folpet in the selected matrices according to the new EU residue definition, which includes phthalimide. Phthalimide is the main metabolite and degradation product of Folpet, although according to recent studies, it could be generated from different sources than Folpet breakdown, such as food processing or analysis by GC.
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Quantification of Folpet and phthalimide in food by gas chromatography and mass spectrometry: Overcoming potential analytical artefacts.
Food chemistry, 2018Co-Authors: José Fernando Huertas-pérez, Marion Ernest, Jesus Varela, Flavia BadoudAbstract:Abstract Accurate quantification of Folpet is problematic because it degrades into phthalimide during sample preparation and analysis by gas chromatography (GC). Thus, EU regulation was recently modified to include phthalimide in the Folpet residue definition. However, recent studies have shown that phthalimide could also be generated from different sources, which could lead to an overestimation of the phthalimide content and therefore to false positives. GC coupled with either negative chemical ionisation and single quadrupole mass spectrometry, or electron ionisation with triple quadrupole mass spectrometry (GC-EI-MS/MS), were evaluated for the determination of Folpet and phthalimide in food. Both methods were validated in 4 different matrices namely apple puree, rice flour, raspberry puree and infant formula. Better selectivity and precision were obtained with GC-EI-MS/MS. Negligible amounts of phthalimide was found in blank matrices, and validation results met the SANTE/11813/2017 criteria in all matrices at the LOQ concentration levels by using GC-EI-MS/MS.
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Artifact-controlled quantification of Folpet and phthalimide in food by liquid chromatography-high resolution mass spectrometry
Food Control, 2018Co-Authors: Flavia Badoud, Marion Ernest, Yves-alexis Hammel, José Fernando Huertas-pérezAbstract:Abstract The European residue definition for the pesticide Folpet has changed in 2016 to include its degradation product phthalimide. According to recent studies, phthalimide could also arise from other sources than Folpet, including formation in the injector of gas chromatography systems from the precursor phthalic acid or phthalic anhydride. A liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry (MS) method was developed for the quantification of Folpet and phthalimide. High resolution MS was deemed necessary to increase the selectivity via accurate mass, as phthalimide and Folpet yielded poor fragmentation. Sample preparation by QuEChERS was optimized to ensure the stability of Folpet and to prevent the contamination of phthalimide from external sources. The method was validated on four matrices from four commodity groups (i.e., high water content, high water and acid content, high starch content and dairy products). Linearity was assessed with r2 > 0.99 over the range 5–200 μg kg−1, repeatability ranged between 6.8% and 14.5%, intermediate precision between 10% and 23.8%, and trueness was within 78.6% and 124.2% with relative standard deviation from 3% to 20%. These performance parameters were all compliant with the analytical requirements stipulated in the SANTE/11813/2017 document. The method was verified on 12 additional matrices from the 4 commodity groups. The present method was suitable for the quantification of Folpet and phthalimide in foods while controlling analytical artifact.