Recent Trends in Solid-Phase Microextraction for the Monitoring of Drugs of Abuse in Wastewater

Wastewater analysis plays a central role in monitoring patterns of drug use within specific populations. It provides objective and real-time estimates of consumption, with minimal ethical concerns. In the current European context, drugs of abuse continue to be detected in wastewater, with varying incidences across countries. Their monitoring enables the prioritisation of public health and legal interventions by healthcare professionals and drug monitoring agencies. Therefore, the development and implementation of efficient methodologies for monitoring drugs of abuse in wastewater samples is of critical importance. This systematic review aims to explore the use of miniaturised sample extraction techniques based on solid-phase microextraction for the determination of drugs of abuse in wastewater. In fact, the extraction procedure must be fast, effective, and selective in order to retain the analytes of interest. Miniaturised techniques have thus emerged as promising alternatives to conventional methods. Magnetic solid-phase extraction (MSPE) and molecularly imprinted polymers (MIPs) represent the most widely applied solid-phase microextraction techniques in recent years for the analysis of drugs of abuse in wastewater. Looking ahead, future perspectives include the development of eco-friendly workflows, automated and time-efficient techniques, increasingly selective sorbents, and robust analytical methods.