In Vivo SPME for Bioanalysis in Environmental Monitoring and Toxicology

Solid-phase microextraction (SPME) is a well-established sample preparation technique in the field of environmental and toxicological studies. The application of SPME has extended from the headspace extraction of volatile compounds to the capturing of short-lived and unstable components of the ecosystem extracted from the living organism via direct immersion of SPME probes into the tissue (in vivo SPME). The development of biocompatible coatings and availability of different calibration approaches enables in vivo sampling of exogenous and endogenous compounds from the living plants and animals without the need for tissue collection. In addition, new geometry designs such as thin-film coatings, needle trap devices, recession needles, coated tips or blades has increased the sensitivity and robustness of in vivo sampling. Here, we present the fundamentals of in vivo SPME technique, including the types of extraction mode, geometry design of the coatings, calibration methods and data analysis methods used in untargeted in vivo SPME. We also discuss recent applications of in vivo SPME in environmental studies and in the analysis of pollutants in plant and animal tissues in addition to in vivo human saliva, breath and skin analysis. In summary, in vivo SPME technique shows great potential for both targeted and untargeted screening of small molecules in the living organisms exposed to the surrounding environment.