Development of a green in-situ derivatization and deep eutectic solvent-based dispersive liquid–liquid microextraction method for analysis of short-chain fatty acids in beverage samples optimized by response surface methodology

Abstract

An in-situ dispersive liquid–liquid microextraction and derivatization method based on deep eutectic solvent has been developed for the analysis of five short chain fatty acids (as model compounds) in different beverage samples prior to their determination by gas chromatography-flame ionization detection. In this method, 2-butanol was used as dispersive solvent derivatization reagent. For this purpose, the sample solution is transferred into a test tube and after dissolving sodium chloride in the solution, a suitable volume of HCl solution is added as catalyst. Thus, a mixture of 2-butanol and ethyl methyl ammonium chloride-carvacrol deep eutectic solvent (as an extraction solvent) is prepared and the mixture is quickly injected into the solution. The analytes are derivatized and extracted into the fine droplets of extracting agent, simultaneously. After centrifugation, an aliquot of the sedimented phase is injected into the separation system. Low limits of detection (0.89–6.6 µg L-1) and quantification (3.1–22.3 µg L-1) were obtained. Good repeatabilities with relative standard deviations ≤9.2% were obtained at the selected three concentrations. Also high enrichment factors, extraction recoveries, and enhancement factors were obtained within the ranges of 223–270, 76–92%, and 1074–1845, respectively. The developed method was successfully used in determination of the analytes in different beverage samples.