Switchable hydrophilicity solvents in analytical chemistry. Five years of achievements

Dissolution dynamics of a binary switchable hydrophilicity solvent–polymer drop into an acidic aqueous phase

“…[7][8][9] SHSs present an economically viable and green alternative to VOCs due to their simplicity to ''switch on'' and ''off'' the hydrophobicity of the solvent with high recoverability coming from the ''switching off'' process. The potential applications of SHSs have already been demonstrated in soybean oil extraction, 10,11 separation of bitumen from oil sands, 12 biofuel extraction from microalgae, 13,14 polystyrene foam 15 and multi-layer packaging recycling, 16,17 liquid-liquid microextraction (SHS-LLME) for analytical chemistry 18,19 and latex formation. 20 In latex formation, binary drops of the SHS and dissolved polymer are made to deposit solid polymer particles by switching off SHS hydrophobicity in an aqueous environment.…”

A comprehensive review on recent developments and future perspectives of switchable solvents and their applications in sample preparation techniques

“…109,110 Over the past ten years, these solvents have become more and more common when using micro-extraction techniques. 111 Such solvents are capable of transitioning between hydrophobic and hydrophilic states, or vice versa. Some of the most often used compounds in the production of switchable hydrophilicity solvents are secondary and tertiary amines.…”

Use of green alternative solvents in dispersive liquid‐liquid microextraction: A review

“…SHSs are solvents consisting of amidines, secondary/tertiary amines, or saturated fatty acids that show the capability of changing their hydrophilicity and, therefore, change from slightly miscible to completely miscible with water by means of a simple change in the aqueous medium. This change in miscibility is usually driven by an acid-base equilibrium after the addition of CO 2 for basic SHSs or CO 3 2for acidic SHSs [12]. In general, the pH change enhances the formation of a water-soluble salt, hence solubilizing the SHS.…”