Sorbents modified by deep eutectic solvents in microextraction techniques

In recent years, considerable attention has been directed towards the employment of green solvents, specifically deep eutectic solvents (DES), in liquid phase microextraction techniques. However, comprehensive and organized knowledge regarding the modification of sorbent surface structures with DES remains limited. Therefore, this paper reviews the application of DES in modifying and improving the properties of sorbents for microextraction techniques. The review begins by explaining the criteria for selecting DES as surface modifiers and the types of sorbents. Subsequently, it delves into the diverse techniques employed to modify sorbents using DES, including dip coating, sol-gel coating, polymer monolith coatings, molecular imprinting, electrochemical deposition, and simultaneous DES formation and sorbent impregnation. The impact of these modifications on sorbent selectivity, and durability, extraction efficiency, and environmental sustainability is critically evaluated. Additionally, this paper discusses the applications of DES-modified sorbents in various types of solid-phase extraction and solid-phase microextraction techniques. The review concludes with a discussion of current challenges and future perspectives in the field, including potential avenues for further research.