Green sample-preparation methods using room-temperature ionic liquids for the chromatographic analysis of organic compounds

Room-temperature ionic liquids (RTILs) are novel solvents composed entirely of ions. They can dissolve a wide range of compounds, while some possess virtually no vapor pressure over a wide temperature range, and have high thermal stability, low toxicity, and low flammability, properties desirable of green solvents. Applications that take advantage for their characteristic properties are starting to appear regularly embodied in techniques, such as liquid-phase microextraction, solid-phase microextraction, and microwave-assisted extraction. In this review, we present a contemporary picture of how, where and when to use ILs in sample-preparation techniques, while recognizing limitations that inhibit their use for some applications. Since the number of potential RTILs is very large, and only a small number have been evaluated in laboratory studies, it is important not to overgeneralize on their potential as general solvents based on this small database of rather limited chemical diversity.