Suspect Screening Analysis of Pooled Human Serum Samples Using GC × GC/TOF-MS

Humans
interact with thousands of chemicals. This study aims to
identify substances of emerging concern and in need of human health
risk evaluations. Sixteen pooled human serum samples were constructed
from 25 individual samples each from the National Institute of Environmental
Health Sciences’ Clinical Research Unit. Samples were analyzed
using gas chromatography (GC) × GC/time-of-flight (TOF)-mass
spectrometry (MS) in a suspect screening analysis, with follow-up
confirmation analysis of 19 substances. A standard reference material
blood sample was also analyzed through the confirmation process for
comparison. The pools were stratified by sex (female and male) and
by age (≤45 and >45). Publicly available information on
potential
exposure sources was aggregated to annotate presence in serum as either
endogenous, food/nutrient, drug, commerce, or contaminant. Of the
544 unique substances tentatively identified by spectral matching,
472 were identified in females, while only 271 were identified in
males. Surprisingly, 273 of the identified substances were found only
in females. It is known that behavior and near-field environments
can drive exposures, and this work demonstrates the existence of exposure
sources uniquely relevant to females.