A two-step gas chromatography-tandem mass spectrometry method for measurement of multiple environmental pollutants in human plasma

Abstract

Individuals are exposed to a wide variety of chemicals over their lifetime, yet current understanding of mixture toxicology is still limited. We present a two-step analytical method using a gas chromatograph-triple quadrupole mass spectrometer that requires less than 1 mL of sample. The method is applied to 183 plasma samples from a study population of children with autism spectrum disorder, their parents, and unrelated neurotypical children. We selected 156 environmental chemical compounds and ruled out chemicals with detection rates less than 20% of our study cohort (n = 61), as well as ones not amenable to the selected extraction and analytical methods (n = 34). The targeted method then focused on remaining chemicals (n = 61) plus 8 additional polychlorinated biphenyls (PCBs). Persistent pollutants, such as p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and PCB congeners 118 and 180, were detected at high frequencies and several previously unreported chemicals, including 2,4,6trichlorophenol, isosafrole, and hexachlorobutadiene, were frequently detected in our study cohort. This work highlights the benefits of employing a multi-step analytical method in exposure studies and demonstrates the efficacy of such methods for reporting novel information on previously unstudied pollutant exposures.

Targeted and Nontargeted Detection and Characterization of Trace Organic Chemicals in Human Serum and Plasma Using QuEChERS Extraction

“…The SPE procedure (Supplementary Figure 1) was based on methods described previously (Caudle et al 2007;Hatcher et al 2007;Johnson et al 2021). SPE cartridges containing 5 g Florisil were purchased from 4 different vendors: Sigma Millipore (Supelclean LC, Darmstadt, Germany), Thermo Scientific (Hypersep), UCT (Enviro-clean), and Waters (Sep-pak).…”

“…Prominent POPs, such as polychlorinated biphenyls (PCBs), pesticides, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polybrominated diphenyl ethers (PBDEs) (Jones and de Voogt 1999), have been analyzed using targeted GC-MS or GC-electron capture detectors (Brevik 1978;Yu et al 2011). Sample preparation techniques for POPs analysis in human samples (eg, serum, plasma) is time consuming and labor intensive, and includes methods such as solid-phase extraction (SPE), Soxhlet extraction, and liquid-liquid extraction (Johnson et al 2021;Loconto et al 2008;Salihovic et al 2013;Yu et al 2020). Alternative methods, such as QuEChERS (quick, easy, cheap, efficient, rugged, and safe), can improve sample throughput, reduce solvent, and provide sufficient recovery for a broad range of analytes (Anastassiades et al 2003).…”