New microextraction techniques in exposome Research: Bridging environmental exposures and human health

Exposome studies encompass comprehensive investigations into the various exposures individual living organisms encounter from exogenous factors throughout their lifetime, and how these exposures may affect their health status. These studies may focus on health risks associated with single chemical exposures or the cumulative effect of multiple chemicals, aiming to elucidate dose−response relationships. Numerous analytical methods are available for measuring contaminants and/or their endogenous metabolites across various matrices, including biofluids, food, air, water, and soil. In recent years, microextraction techniques have gained increasing relevance in exposome research due to their ability to enhance analytical throughput while minimizing invasion to the systems under study. Among these techniques, solid phase microextraction (SPME), a well-established sample preparation method in environmental and toxicological studies, has gained particular attention for its ability to extract a wide range of compounds, including short-lived and unstable compounds, directly from living organisms (in vivo SPME). As a result, SPME is gaining traction in exposome studies for its ability to both detect exogenous compounds in environmental matrices and track the fate of these contaminants, including their metabolism, accumulation, and metabolic effects in living systems. This review explores recent applications of microextraction in exposome research, highlighting the advantages of different coatings, adsorbent chemistries, and geometric designs— such as fiber SPME, thin film SPME (TFME), needle trap devices (NTDs), coated tips (arrow-SPME), blade SPME, and the newly introduced swab-SPME—for the analysis of exogenous and endogenous compounds in environmental samples and in biological matrices. We also examine the emerging applications of direct-MS coupled with SPME in exposome research and provide an overview of the significant potential of SPME in both targeted and untargeted screening of low molecular weight molecules within exposomics and metabolomics applications.