Novel Method for Simultaneously Untargeted Metabolome and Targeted Exposome Analysis in One Injection

Serum endogenous metabolites and
coexisting exogenous compounds
are closely related to human health. Metabolomics often uses high-resolution
mass spectrometry (HRMS), but current exposomics studies typically
rely on triple quadrupole tandem mass spectrometry due to lower concentrations
in the body. As a result, metabolome-exposome-wide association studies
(mEWAS) require a combination of untargeted metabolomics and several
targeted exposomics methods to measure more exposures, leading to
increased time and sample consumption. In this study, a novel method
was proposed by leveraging the advantages of recently introduced Zeno
MRMHR technology; it allows for the simultaneous acquisition
of the metabolome in HRMS and the exposome in multiple reaction monitoring
(MRM) modes in one injection. The signal responses for exogenous compounds
in MRM were comparable to those of metabolites in HRMS. This method
was rigorously validated, and all exogenous standards had relative
standard deviations (RSDs) below 20% for intraday and interday repeatability.
Over 90% of metabolic features exhibited RSDs below 20% in these assessments.
The method also had a broad quantification range, with lower limits
of quantification (LLOQ) from 0.1 to 25 ng/mL and higher limits of
quantification (HLOQ) from 2.5 to 1000 ng/mL. This approach was demonstratively
applied to a type 2 diabetes mellitus cohort to identify serum risk
factors and study the metabolome–exposome association. To our
knowledge, this study is the first implementation of a unified method
for the simultaneous analysis of endogenous metabolites in the untargeted
mode and 210 exogenous compounds in the targeted mode in one injection,
offering a novel tool for mEWAS research.