Applications of ionic liquids in the microextraction of pesticides: A mini-review

Abstract

The development of preferably simple, fast, sensitive, selective and relatively inexpensive methods for the determination of pesticide residues in food and environmental samples is essential. The design of methods with the above attributes can pose challenges, especially for complex food and environmental matrices. In this sense, isolation and pre-concentration of pesticides in such matrices are required, and are considered an important step towards the determination of low levels of these analytes. Another characteristic of an analytical approach that is gaining increasing focus is the "greenness" of the overall method, most notably in the avoidance of the use of potentially harmful organic solvents. In this vein, scientists are looking for environmentally friendlier alternatives to organic solvents. Ionic liquids (ILs) suitable for use in extraction or sample preparation procedures represent one such alternative. A better understanding of the nature of the IL-based extractions and their impact on pesticide analysis is important for their successful applicability. Due to their unique properties such as polarity, adjustable viscosity, miscibility and surface tension, and their interactions thereof (with respect to sample matrices and analytes) ILs have gained widespread attention and popularity in many areas of analytical chemistry, including modern sample preparation technologies. This mini-review critically discusses recent and/or interesting applications of ILs in the microextraction of pesticides. The topics covered include a brief overview of ILs, their structures and interactions, and their applications as extractants in liquid-phase microextraction and solid-phase microextraction.