Low-density solvent-based liquid-liquid microextraction for separation of trace concentrations of different analytes

The development of analytical chemistry in the last decade is inextricably linked with the involvement of the concepts of “green” chemistry. In analytical practice, these trends are primarily realized in the sample pretreatment. This is most clearly manifested in the search for new solvents for analytical purposes. Low density solvents (LDSs), such as deep eutectic solvents (DESs), supramolecular solvents (SUPRAs), switchable hydrophobicity solvents (SHSs), and some others have been actively used in analytical chemistry for the last ten years, and since then the number of publications in this direction has been steadily growing. In this review, an attempt was made to consider the possibilities, advantages and disadvantages of LDSs and the corresponding procedures of liquid-liquid microextraction (LLME). The analytical application of LDSs (2018–2023) for the determination of inorganic and organic analytes in various matrices is discussed in this article. Some new trends in the use of LDSs in LLME are noted and prospects for further development are outlined.