Green solvents in microextraction of pharmaceuticals: Application and comparison of deep eutectic solvents and ionic liquids

Forward-looking, sustainable, and green approaches in analytical chemistry have become a significant topic worldwide. This has attracted considerable attention from scientists in improving methods for analyzing a broad area of analytes and samples, such as pharmaceuticals in biological matrices. These enhancements generally adhere to principles of Green Chemistry (GC) and Green Analytical Chemistry (GAC). To align with these principles, utilizing green materials and solvents, such as deep eutectic solvents (DESs) and ionic liquids (ILs), has proven to be highly effective in making analytical chemistry approaches more environmentally friendly. Building on these principles, we consider specific applications of green solvents in microextraction techniques by analyzing published studies, which have focused on developing solid-phase and liquid-phase microextraction of pharmaceuticals, using DESs and ILs in biological samples. Here, we explored the applicability of these green solvents in microextraction approaches and examined how the analytical results might be affected. We also focused on the different types of DESs and ILs, their characteristics, their ecotoxicity and biodegradability. Furthermore, we examined the advantages and disadvantages of these solvents, addressing both aspects common to all microextraction methods and those specific to individual approaches. Finally, we highlighted the current challenges in this field and outlined future perspectives to overcome them.