Abstract
New psychoactive substances (NPS) are substances of abuse that have posed a significant threat in recent years. Accurate detection of NPS presents a major analytical challenge due to their structural diversity and their rapid emergence and disappearance from the market. In this context, given the wide structural variety of the different classes of NPS developed to circumvent legislation and the difficulties authorities face in detecting these compounds, the objective of this work was to perform a systematic review of the main analytical methods recently validated for the identification of NPS in biological matrices, as well as the primary sample preparation methods used in the detection process. The methodology followed the PRISMA-S guidelines, and studies were selected based on predefined inclusion and exclusion criteria. Ultimately, 74 studies were included in this review for data extraction. Blood was the most commonly analyzed biological matrix for the identification of NPS, and solid-phase extraction was the most frequently employed sample preparation method. Liquid chromatography, using a C18 column as the stationary phase and coupled with high-resolution mass spectrometry (LC-HRMS), emerged as the most commonly used analytical technique due to its high sensitivity and specificity in identifying NPS, with stimulants being the most prevalent class in the included studies. It is important to emphasize that there is no single ideal method for identifying NPS. A combination of different analytical tools may often be required to evaluate these substances, given their frequent structural modifications. This dynamic nature necessitates the continuous updating of detection methods by authorities.