Department of Chemistry, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa.
Department of Chemistry, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa.
Talanta. 2021 Mar 1;224:121807. doi: 10.1016/j.talanta.2020.121807. Epub 2020 Oct 28.
Switchable solvents are new generation solvents that are environmentally friendly and can be used for the effective pre-concentration of pesticide residues in food and environmental matrices. They have physico-chemical properties that can be switched abruptly and reversibly between two opposite forms. The common switchable solvents used commonly during pesticide pre-concentration involve polarity switch. Such solvent switch between hydrophobic and hydrophilic forms during pesticide pre-concentration. Secondary and tertiary amines are typical switchable hydrophilicity solvents. The amines are hydrophobic but they abruptly and reversibly switch to their hydrophilic forms on addition of CO to them. The application of amine-based switchable solvents during pre-concentration of pesticide residue in food and environmental samples are discussed in this paper. Medium-chain fatty acids can also be used as switchable solvents. Their switch between hydrophobic and hydrophilic forms is usually triggered by pH changes. Applications of fatty acid-based switchable solvents during pre-concentration of pesticide residues are reviewed in this paper. Switchable solvent-based micro-extraction can be combined with other pre-concentration techniques to enhance selectivity resulting in clean chromatograms. This paper has a section dedicated to the application of hyphenated switchable solvent-based micro-extraction techniques during pre-concentration of pesticides in food and environmental samples. In addition, the challenges associated with the use of switchable solvents during micro-extraction of pesticide residues are also discussed.
可切换溶剂是新一代的溶剂，对环境友好，可用于有效浓缩食品和环境基质中的农药残留。它们具有物理化学性质，可以在两种相反的形式之间突然且可逆地切换。在农药浓缩过程中常用的常见可切换溶剂涉及极性切换。在农药浓缩过程中，这种溶剂在疏水性和亲水性之间切换。仲胺和叔胺是典型的可切换亲水性溶剂。胺类是疏水性的，但在加入 CO 后，它们会突然且可逆地转变为亲水性形式。本文讨论了基于胺的可切换溶剂在食品和环境样品中农药残留浓缩过程中的应用。中链脂肪酸也可用作可切换溶剂。它们在疏水性和亲水性之间的切换通常由 pH 值变化触发。本文综述了基于脂肪酸的可切换溶剂在农药残留浓缩过程中的应用。基于可切换溶剂的微萃取可以与其他浓缩技术结合使用，以提高选择性，从而得到干净的色谱图。本文有一节专门介绍在食品和环境样品中浓缩农药时，联用可切换溶剂的微萃取技术的应用。此外，还讨论了在农药残留微萃取过程中使用可切换溶剂所面临的挑战。
