Hydrophobic deep eutectic solvents in microextraction techniques–A review

Over the past decade, deep eutectic solvents (DES) have been widely studied and applied in sample preparation techniques. Until recently, most of the synthesized DES were hydrophilic, which prevented their use in the extraction of aqueous samples. However, after 2015 studies on the synthesis and application of hydrophobic deep eutectic solvents (HDES) has rapidly expanded. Due to unique properties of HDES i.e. density, viscosity, acidity or basicity, polarity and volatility, good extractabilities for various target analytes, which could be altered by careful selection of the hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) components, HDES are promising alternatives to the traditional organic…