Fig. 3: Adaptation of reference standardization to GC–HRMS provides automated workflow for quantification of identified environmental chemicals.

a Reference standardization (RS) is a validated single-point quantification method used in liquid chromatography–high-resolution mass spectrometry (LC–HRMS) for automated measurement in high-throughput analyses. The method relies upon pooled reference materials that are calibrated relative to external calibration curves and relative to other pooled reference materials. These pooled reference materials are analyzed before and after each batch of samples, so that concentrations of environmental chemicals detected in the samples can be quantified relative to concentrations in the pooled reference materials, which may be validated by external calibration with high-resolution (Hi-res) chemical library. b We used dilution series of environmental chemical standards to validate quantification by reference standardization; mean concentrations of plasma samples (n = 20 biologically independent samples) are presented with positive SEM by two methods. c We determined response factors (RF) using stable isotopes to validate quantification by reference standardization; mean concentrations of lung samples (n = 11 biologically independent samples) are presented with positive SEM by two methods. Spearman’s correlation |ρ| was presented. DDE dichlorodiphenyldichloroethylene, PBDE polybrominated diphenyl ethers, PCB polychlorinated biphenyls. Pesticides are colored in purple, with polychlorinated biphenyls (PCBs) in teal, and polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyl (PBB) in yellow-green. Source data are provided as a Source Data file.