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Development and Applications of Gas Chromatography with Low- and High-Resolution Mass Spectrometry in Assessing Human and Wildlife Exposure to Organic Contaminants.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Development and Applications of Gas Chromatography with Low- and High-Resolution Mass Spectrometry in Assessing Human and Wildlife Exposure to Organic Contaminants./
作者:	Travis, Steven C.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
面頁冊數:	239 p.
附註:	Source: Dissertations Abstracts International, Volume: 82-09, Section: B.
Contained By:	Dissertations Abstracts International82-09B.
標題:	Analytical chemistry. -
電子資源:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28315251
ISBN:	9798582508724

Development and Applications of Gas Chromatography with Low- and High-Resolution Mass Spectrometry in Assessing Human and Wildlife Exposure to Organic Contaminants.
Travis, Steven C.

Development and Applications of Gas Chromatography with Low- and High-Resolution Mass Spectrometry in Assessing Human and Wildlife Exposure to Organic Contaminants. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 239 p.

Source: Dissertations Abstracts International, Volume: 82-09, Section: B.

Thesis (Ph.D.)--State University of New York at Buffalo, 2021.

This item must not be sold to any third party vendors.

Organic contaminant exposure is a concern for both humans and wildlife due to long lasting and potential harmful effects. The research presented here investigates to organic contaminant exposure in both humans and wildlife. Sample preparation, instrument methods, and data processing procedures were developed, optimized, and validated. First, targeted analysis using low resolution mass spectrometry was utilized to measure organic contaminants in wildlife tissues and silicone wristband personal samplers. More advanced high resolution mass spectrometry was then optimized for unknown analysis of silicone wristbands. Chapter 1 provides an overview of legacy and emerging pollutants including their manufacturing history, applications, and toxicity. In addition, various analytical practices are discussed, specifically gas chromatography coupled with different mass spectrometry techniques. Non-target analysis is then introduced as a tool to expand our knowledge of the entire contaminant profile in environmental samples.In Chapter 2, method development for the analysis of persistent organic pollutants (POPs) in chicken liver tissue is discussed. Several sample preparation protocols, including extraction and cleanup techniques, were investigated. First, pressurized liquid extraction as well as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) extraction were explored as feasible methods to recover contaminants from chicken liver matrix. Cleanup methods including solid-phase extraction (SPE) and dispersive-SPE (dSPE) were tested to effectively remove sample matrix and retain the contaminants of concern in samples. The final sample preparation method that provided the most capable recoveries included a modified QuEChERS extraction and a dSPE cleanup. Gas chromatography coupled with tandem mass spectrometry was utilized for sample analysis for 42 analytes. Optimization of chromatography conditions as well as mass fragmentation characteristics are also discussed. Chapter 3 discusses the application of the method developed in Chapter 2 in samples from four life stages of the common tern (Sterna hirundo), a threatened species in New York State, collected post-mortem in the Buffalo-Niagara region. Brains and livers were analyzed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and the insecticide p,p'-dichlorodiphenyltrichloroethane (DDT) and its two metabolites p,p'- dichlorodiphenyldichloroethylene (DDE) and p,p'-dichlorodiphenyldichloroethane (DDD). Detectable concentrations of PCBs and PBDEs were observed in all samples; concentrations of total PCBs ranged from 5.59 to 2,490 ng/g wet weight (ww), total PBDEs ranged from 1.09 to 494 ng/g ww, and DDE metabolite ranged from 0.56 to 637 ng/g ww. Analysis of the primary food source for terns in the Buffalo-Niagara region, emerald shiners (Notropis atherinoides), revealed that all three classes of POPs had similar contaminant profiles in the fish to those in the brains and livers of tern samples. Overall, small chicks contained greater concentrations of pollutants than medium chicks and juveniles, likely from maternal loading to eggs. These results underline the persistence of these legacy contaminants in the Great Lakes, despite their banning, and their biomagnification in threatened species through food web interactions.In Chapter 4, silicone wristbands were examined for the use of personal passive samplers. Several methods for the sample preparation of silicone wristbands were investigated including different solvent extractions along with SPE cleanup using various stationary phases and multiple cleanup steps. Overall results showed that special consideration should be taken when choosing which pairing of pre-cleaning and extraction protocols are used. If solvent extraction using ethyl acetate is used for pre-cleaning then similar solvents should be utilized for post deployment extraction and more aggressive solvents and extraction techniques like DCM and Soxhlet should be avoided. Furthermore, recovery experiments using unworn wristbands may be used for initial optimization but worn wristbands should be prepared to confirm the effectiveness of the method in true matrix. Chapter 5 implemented the method developed in the work discussed in Chapter 4 in ongoing research activities in Montevideo, Uruguay which aim to monitor chemical exposures in a cohort of elementary school children. The silicone wristbands were worn by 24 children for 7 days; they were quantitatively analyzed using gas chromatography with tandem mass spectrometry for 45 chemical pollutants, including PCBs, pesticides, PBDEs, organophosphorus flame retardants (OPFRs), and novel halogenated flame-retardant chemicals (NHFRs). All classes of chemicals, except NHFRs, were identified in the passive samplers. The average number of analytes detected in each wristband was 13 ±3. OPFRs were consistently the most abundant class of analytes detected. Median concentrations of ΣOPFRs, ΣPBDEs, ΣPCBs, and DDT and its metabolites (DDE and DDD) were 1020, 3.00, 0.52 and 3.79 ng/g wristband, respectively. Two major findings result from this research; differences in trends of two OPFRs (TCPP and TDCPP) are observed between studies in Uruguay and the United States, and the detection of DDT, a chemical banned in several countries, suggests that children's exposure profiles in these settings may differ from other parts of the world. This was the first study to examine children's exposome in South America using silicone wristbands and clearly points to a need for further studies.In Chapter 6, gas chromatography coupled to OrbitrapTM mass spectrometry (GCOrbitrapTM MS) was used to simultaneously perform suspect (in-house database) and unknown screening (vendor databases) of extracts from wristbands worn by volunteers. The goal of this study was to optimize a workflow that allows detection of low-levels of priority pollutants, with high reliability. In this regard, a data processing workflow for GC-OrbitrapTM MS was developed using a mixture of 123 environmentally relevant standards consisting of pesticides, flame retardants, organophosphate esters, and polycyclic aromatic hydrocarbons as test compounds. The optimized unknown screening workflow using a search index threshold of 750 resulted in positive identification of 70 analytes in validation samples, and reduction in the number of false positives by over 50%. An average of 26 compounds with high confidence identification, seven level 1 compounds and 19 level 2, were observed in worn wristbands; of these. The data was further analyzed via suspect screening and retrospective suspect screening to identify an additional 36 compounds of exposure. This study provides three important findings: (1) a clear evidence of the importance of sample cleanup in addressing complex sample matrices for unknown analysis, (2) a valuable workflow for the identification of unknown contaminants in silicone wristband samplers using HRMS-EI data, and (3) a novel application of GC-OrbitrapTM MS for the unknown analysis of organic contaminants that can be used in exposomics studies.

ISBN: 9798582508724Subjects--Topical Terms:

3168300
Analytical chemistry.
Subjects--Index Terms:

Mass spectrometry

Development and Applications of Gas Chromatography with Low- and High-Resolution Mass Spectrometry in Assessing Human and Wildlife Exposure to Organic Contaminants.
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Non-target analysis is then introduced as a tool to expand our knowledge of the entire contaminant profile in environmental samples.In Chapter 2, method development for the analysis of persistent organic pollutants (POPs) in chicken liver tissue is discussed. Several sample preparation protocols, including extraction and cleanup techniques, were investigated. First, pressurized liquid extraction as well as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) extraction were explored as feasible methods to recover contaminants from chicken liver matrix. Cleanup methods including solid-phase extraction (SPE) and dispersive-SPE (dSPE) were tested to effectively remove sample matrix and retain the contaminants of concern in samples. The final sample preparation method that provided the most capable recoveries included a modified QuEChERS extraction and a dSPE cleanup. Gas chromatography coupled with tandem mass spectrometry was utilized for sample analysis for 42 analytes. Optimization of chromatography conditions as well as mass fragmentation characteristics are also discussed. Chapter 3 discusses the application of the method developed in Chapter 2 in samples from four life stages of the common tern (Sterna hirundo), a threatened species in New York State, collected post-mortem in the Buffalo-Niagara region. Brains and livers were analyzed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and the insecticide p,p'-dichlorodiphenyltrichloroethane (DDT) and its two metabolites p,p'- dichlorodiphenyldichloroethylene (DDE) and p,p'-dichlorodiphenyldichloroethane (DDD). Detectable concentrations of PCBs and PBDEs were observed in all samples; concentrations of total PCBs ranged from 5.59 to 2,490 ng/g wet weight (ww), total PBDEs ranged from 1.09 to 494 ng/g ww, and DDE metabolite ranged from 0.56 to 637 ng/g ww. Analysis of the primary food source for terns in the Buffalo-Niagara region, emerald shiners (Notropis atherinoides), revealed that all three classes of POPs had similar contaminant profiles in the fish to those in the brains and livers of tern samples. Overall, small chicks contained greater concentrations of pollutants than medium chicks and juveniles, likely from maternal loading to eggs. These results underline the persistence of these legacy contaminants in the Great Lakes, despite their banning, and their biomagnification in threatened species through food web interactions.In Chapter 4, silicone wristbands were examined for the use of personal passive samplers. Several methods for the sample preparation of silicone wristbands were investigated including different solvent extractions along with SPE cleanup using various stationary phases and multiple cleanup steps. Overall results showed that special consideration should be taken when choosing which pairing of pre-cleaning and extraction protocols are used. If solvent extraction using ethyl acetate is used for pre-cleaning then similar solvents should be utilized for post deployment extraction and more aggressive solvents and extraction techniques like DCM and Soxhlet should be avoided. Furthermore, recovery experiments using unworn wristbands may be used for initial optimization but worn wristbands should be prepared to confirm the effectiveness of the method in true matrix. Chapter 5 implemented the method developed in the work discussed in Chapter 4 in ongoing research activities in Montevideo, Uruguay which aim to monitor chemical exposures in a cohort of elementary school children. The silicone wristbands were worn by 24 children for 7 days; they were quantitatively analyzed using gas chromatography with tandem mass spectrometry for 45 chemical pollutants, including PCBs, pesticides, PBDEs, organophosphorus flame retardants (OPFRs), and novel halogenated flame-retardant chemicals (NHFRs). All classes of chemicals, except NHFRs, were identified in the passive samplers. The average number of analytes detected in each wristband was 13 ±3. OPFRs were consistently the most abundant class of analytes detected. Median concentrations of ΣOPFRs, ΣPBDEs, ΣPCBs, and DDT and its metabolites (DDE and DDD) were 1020, 3.00, 0.52 and 3.79 ng/g wristband, respectively. Two major findings result from this research; differences in trends of two OPFRs (TCPP and TDCPP) are observed between studies in Uruguay and the United States, and the detection of DDT, a chemical banned in several countries, suggests that children's exposure profiles in these settings may differ from other parts of the world. This was the first study to examine children's exposome in South America using silicone wristbands and clearly points to a need for further studies.In Chapter 6, gas chromatography coupled to OrbitrapTM mass spectrometry (GCOrbitrapTM MS) was used to simultaneously perform suspect (in-house database) and unknown screening (vendor databases) of extracts from wristbands worn by volunteers. The goal of this study was to optimize a workflow that allows detection of low-levels of priority pollutants, with high reliability. In this regard, a data processing workflow for GC-OrbitrapTM MS was developed using a mixture of 123 environmentally relevant standards consisting of pesticides, flame retardants, organophosphate esters, and polycyclic aromatic hydrocarbons as test compounds. The optimized unknown screening workflow using a search index threshold of 750 resulted in positive identification of 70 analytes in validation samples, and reduction in the number of false positives by over 50%. An average of 26 compounds with high confidence identification, seven level 1 compounds and 19 level 2, were observed in worn wristbands; of these. The data was further analyzed via suspect screening and retrospective suspect screening to identify an additional 36 compounds of exposure. This study provides three important findings: (1) a clear evidence of the importance of sample cleanup in addressing complex sample matrices for unknown analysis, (2) a valuable workflow for the identification of unknown contaminants in silicone wristband samplers using HRMS-EI data, and (3) a novel application of GC-OrbitrapTM MS for the unknown analysis of organic contaminants that can be used in exposomics studies.
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