Determinations of new psychoactive substances in biological matrices with focus on microextraction techniques: a review of fundamentals and state-of-the-art extraction methods

Purpose This review article provides a detailed discussion of studies in which microextraction techniques are applied for the determination of new psychoactive substances (NPS) in biological samples. Definitions and classifications of NPS are highlighted as well as the fundamentals of the microextraction techniques used in their analyses. Methods A complete literature search was carried out with PubMed, Scopus and the World Wide Web using relevant keywords, e.g., NPS, microextraction and biological fluids. Results The determinations of NPS in biological samples remain a challenge for analytical laboratories due to its wide diversity of compounds. The utilization of microextraction techniques in this context is still not many. However, the 96 deep well plate for microextraction and microextraction by packed sorbent (MEPS) can be highlighted as the most explored configurations. Microextraction approaches have the potential to be further improved and optimized to provide rapid and low-cost analyses with reliable results. Conclusions There is a wide scope of microextraction techniques to be explored in the field of toxicology and NPS determinations. These techniques are compatible with recent trends of automation and miniaturization, which can enable a straightforward workflow for NPS analyses.