Steven C Travis1, Katarzyna Kordas2, Diana S Aga1. 1. Department of Chemistry, University at Buffalo, The State University of New York (SUNY) Buffalo, New York, 14260, United States. 2. Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York (SUNY) Buffalo, New York, 14214, United States.
Abstract
RATIONALE: Silicone wristbands have emerged as valuable passive samplers for monitoring of personal exposure to environmental contaminants in the rapidly developing field of Exposomics. Once deployed, silicone wristbands collect and hold a wealth of chemical information that can be interrogated using high resolution mass spectrometry (HRMS) to provide a broad coverage of chemical mixtures. METHODS: Gas chromatography coupled to OrbitrapTM mass spectrometry (GC/OrbitrapTM 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. RESULTS: 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. CONCLUSIONS: 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. This article is protected by copyright. All rights reserved.
RATIONALE: Silicone wristbands have emerged as valuable passive samplers for monitoring of personal exposure to environmental contaminants in the rapidly developing field of Exposomics. Once deployed, silicone wristbands collect and hold a wealth of chemical information that can be interrogated using high resolution mass spectrometry (HRMS) to provide a broad coverage of chemical mixtures. METHODS: Gas chromatography coupled to OrbitrapTM mass spectrometry (GC/OrbitrapTM 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. RESULTS: 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. CONCLUSIONS: 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. This article is protected by copyright. All rights reserved.