Deep eutectic solvent-functionalized metal-organic frameworks in sorptive extraction techniques and their applications – A review

Metal-organic frameworks (MOFs) are porous adsorbents that get much attention in sorptive extraction techniques due to the availability of various structures and properties. MOFs are functionalized with a variety of materials to enhance their extraction ability. Green deep eutectic solvents (DESs) are an emerging solvent for MOF functionalization. Functionalization of MOFs with green deep eutectic solvents (DESs) improves the porosity, structural properties, active sites, hydrogen bonding capability, reusability, and extraction efficiency of deep eutectic solvent-functionalized metal–organic frameworks (DES@MOFs). This review briefly examines the benefits and drawbacks of MOF materials. In addition, the promising properties, classification, and preparation approaches for DESs are discussed in detail. This review also emphasizes the various sorptive extraction techniques, including solid-phase extraction (SPE), solid-phase microextraction (SPME), and magnetic solid-phase extraction (MSPE) reported DES@MOFs as a sorbent for a variety of analytes. A comparative analysis is presented to determine which technique is most appropriate among the reported techniques. Furthermore, the applications of DES@MOFs in pharmaceutical, dye, heavy metal, and pesticide analysis are discussed in various aspects and summarized in a table.