Switchable-hydrophilicity solvent-based microextraction combined with gas chromatography for the determination of nitroaromatic compounds in water samples

A simple, fast, sensitive, and low-cost method was developed for the quantification of nitroaromatic compounds in water samples based on CO₂ -assisted liquid-phase microextraction using a switchable-hydrophilicity solvent followed by gas chromatography detection. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible or immiscible upon the addition or removal of CO₂ as a reagent. Experimental parameters affecting the extraction efficiency such as the volume of acceptor phase, the volume of donor phase, pH of donor phase, ionic strength, and extraction time were investigated. Under the optimal conditions, detection limits and preconcentration factors were obtained in the ranges of 0.9-1.8 μg/L and 132-138, respectively. Also, the extraction recoveries of water samples were above 88%. Finally, the developed method was successfully applied to the determination of nitroaromatic compounds in real water samples.