Enhancing liquid-phase microextraction efficiency through chemical reactions

Liquid-phase microextraction (LPME) is a miniaturized extraction technique with a similar extraction principle to liquid-liquid extraction. In LPME, extraction and preconcentration can be performed in a single step. The basic LPME configuration is that in which extraction involves a single drop of solvent. Another mode of LPME, which entails the use of a porous membrane assisted hollow fiber LPME (HF-LPME) and it is suitable for direct extraction of complex environmental matrices. A more recent LPME development is dispersive liquid-liquid microextraction that has attracted tremendous interest. LPME has the versatility to incorporate chemical reactions in order to enhance extractability and impart compatibility of the final extract with analytical instrumentation. This review focuses on recent developments in LPME involving chemical reactions as part of the extraction process. Reactions that improve the sensitivity of LPME, including ion-pair extraction, complexation, chemical derivatization, phase transfer catalysis, and nanoparticle-assisted chemical reactions are given prominence. (C) 2019 Elsevier B.V. All rights reserved.