A novel methodology based on solvents less dense than water through dispersive liquid–liquid microextraction: application in quantitation of l-ascorbate in fruit juices and soft drinks by fiber optic-linear array detection spectrophotometry

Abstract

In this study a novel methodology is proposed for utilizing solvents less dense than water by using a dispersive liquid–liquid microextraction (DLLME) technique. Conventional microextraction vessels and facile strategy have been used. We have avoided using routine microextraction solvents in the DLLME procedure that are mostly chlorinated, dense, environmentally hazardous and expensive which limits the application of this method to some extent. The aforesaid process has been combined with fiber optic-linear array detection spectrophotometry (FO-LADS) with charge-coupled device (CCD) detector benefiting of a micro-cell. L-Ascorbate was selected as a model compound and the proposed method was carried out for preconcentration and assay of iodine produced by reduction of potassium iodate in fruit juices, soft drinks and pharmaceutical preparations. The influences of the various analytical parameters on the microextraction procedure and oxidation reaction have been evaluated and optimized. The accuracy of the method was confirmed by parallel analyses as the reference method (ISO 6557/2). The calibration curve was linear in the range of 1.76–26.40 μg mL⁻¹ of L-ascorbate with a correlation coefficient (r) of 0.9912. The LOD obtained from the calibration curve was 0.40 μg mL⁻¹.