A comprehensive non-targeted analysis study of the prenatal exposome

Recent technological advances in mass spectrometry have enabled us to screen biological samples for a very broad spectrum of chemical compounds allowing us to more comprehensively characterize the human exposome in critical periods of development. The goal of this study was three-fold: 1) to analyze 590 matched maternal and cord blood samples (total 295 pairs) using non-targeted analysis (NTA); 2) examine the differences in chemical abundance between maternal and cord blood samples; and 3) examine the associations between exogenous chemicals and endogenous metabolites. We analyzed all samples with high-resolution mass spectrometry (HRMS) using liquid chromatography – quadrupole time-of-flight mass spectrometry (LC-QTOF/MS), in both positive and negative electrospray ionization modes (ESI+ and ESI-) and in soft ionization (MS) and fragmentation (MS/MS) modes for prioritized features. We confirmed 19 unique compounds with analytical standards, we tentatively identified 73 compounds with MS/MS spectra matching, and we annotated 98 compounds using an annotation algorithm. We observed 103 significant associations in maternal and 128 in cord samples between compounds annotated as endogenous and compounds annotated as exogenous. An example of these relationships was an association between 3 poly and perfluoroalkyl substances (PFAS) and endogenous fatty acids in both the maternal and cord samples indicating potential interactions between PFAS and fatty acid regulating proteins.