Fig. 1: A new analytic approach is needed to support health research on extensive and diverse chemical exposures of humans.

Targeted analyses for a limited number of chemicals are available using mass spectrometry. Left: Multistep processing is used for targeted detection of low abundance of environmental chemicals. MS: mass spectrometry. Right: Recovery of chemicals differs by sample-preparation procedures. Standard reference material NIST SRM-1958 was analyzed using solid-phase extraction (SPE) and liquid–liquid extraction (LLE). Middle: Addition of stable isotopic internal standards during the procedure allows correction for variability of recovery due to losses during processing. The multistep processing has potential for contamination at each step, decreases sample throughput, increases cost, and is not suitable for untargeted analysis because there is no way to correct for variable recovery. Source data are provided as a Source Data file for chromatography of SPE and LLE for polybrominated biphenyl (PBB)-153 and polychlorinated biphenyl (PCB)-18.