Abstract
Dried blood spots (DBS) are an established sample type, widely used in newborn screening programs for monitoring metabolic diseases. Their minimally invasive nature offers great promise for assessing chemical exposures, particularly during early life stages and in large-scale epidemiological studies. However, comprehensive evaluations of key analytical parameters such as extraction efficiency and matrix effects across multiple chemical classes remain limited. Moreover, the promising approach of broadly combining targeted and non-targeted mass spectrometric data evaluation remains unexplored in DBS small-molecule omics. Here, we present an optimized LC-HRMS workflow for combined exposomic and metabolomic analysis in DBS samples. Four extraction protocols were systematically compared, with analytical performance evaluated for >200 structurally diverse toxicants, pollutants, and other key biomarkers. The optimized protocol demonstrated acceptable recoveries (60–140%) and reproducibility (median RSD: 18%) for a majority of compounds. Matrix effects showed a median value of 76% (median RSD: 14%). In a proof-of-principle study, twelve exposure compounds of the target panel with varied physicochemical properties were identified in real-life samples, with several reported for the first time in DBS biomonitoring. Complementary non-targeted analysis further expanded the detectable chemical space, enabling reliable annotation of additional exposures. Moreover, high-confidence identification of endogenous metabolites, including amino acids, biogenic amines, fatty acids and acylcarnitines demonstrated the capacity to capture a broad snapshot of the human metabolome. These findings support the use of DBS for integrated exposomic and metabolomic applications, providing toxicological and biological insights from low-volume samples in both, prospective and retrospective studies.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
This work was supported by the University of Vienna via the Exposome Austria Research Infrastructure, the Austrian Federal Ministry of Education, Science and Research (project DigiOmics4AT) and the Austrian Federal Ministry for Climate Protection, Environment, Energy, Mobility, Innovation and Technology (BMK)
Author Declarations
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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
The study approved by the ethics committee of the Medical University of Vienna (application number 1716/2023).
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Data Availability
Raw mass spectrometric data will be made soon available via Metabolights
