Exposomic Analysis of Human Plasma, Urine, and Fecal Samples

High-resolution mass spectrometry (HRMS) is the gold-standard technique for comprehensively profiling chemical exposures in complex human matrices, making it a powerful analytical tool for advancing human exposome analysis. Yet the scarcity of HRMS reference data, including collision cross section (CCS) measurements from ion mobility-mass spectrometry (IM-MS) and MS/MS fragmentation spectra , hinders confident structural annotation of exposome molecules across laboratories. We therefore developed ToxBase, a multidimensional (m/z, retention time, CCS, MS/MS) reference database for over 2000 chemicals sources from the U.S. Environmental Protection Agency's ToxCast chemical library. Built via high-throughput liquid chromatography-ion mobility-tandem mass spectrometry (LC-IM-MS/MS), the ToxBase database comprises 3598 precursor ions spanning 2075 unique compounds with excellent precision (98.8% of compounds display inter-day CCS RSDs less than 1%) and strong cross-platform agreement. A high-quality MS/MS reference library of the fragmented precursors was assembled using targeted data-dependent acquisition.