Shaker-Assisted Liquid–Liquid Microextraction Followed by Solidification of Floating Organic Droplet and Back-Extraction Procedure besides Partial Least Squares Regression for Simultaneous Spectrophotometric Determination of Benzoic Acid and Sorbic Acid

Abstract

A shaker-assisted liquid–liquid microextraction followed by solidification of floating organic droplet and the final back-extraction method (SALLME-SFOD-BE) was introduced for the simultaneous quantification of benzoic acid (BA) and sorbic acid (SA) (as the model analytes) in different kinds of food products. The presented method used partial least squares calibration and UV–Vis detection. Then, the organic solvent was solidified and collected from the solution. Finally, the extracted analytes were back-extracted into an alkaline solution and analyzed by UV–Vis. Under the optimized condition, the calibration graph was linear in the range of 1–200 ng mL−1 and 1–250 ng mL−1 (R 2 > 0.995) for BA and SA, respectively. The limits of detection (LODs) of 0.5 ng mL−1 and 0.6 ng mL−1 were determined for BA and SA, respectively. The inter-day relative standard deviations (RSDs) were in the range of 2.9–3.1% and 2.6–2.8% for BA and SA, respectively. The intra-day RSDs were also in the range of 2.6–2.9% and 2.4–2.7%, respectively. The calculated enrichment factor (EF) and percent enrichment recovery (ER%) were within the range of 16.4–16.6 and 98–99 for BA and SA, respectively. The method was used for the determination of selected model analytes in real samples, and satisfactory results were obtained. Since very simple instruments were used, this method is affordable, efficient and convenient for extraction and simultaneous determination of BA and SA in real samples.