A novel vortex-assisted liquid-liquid microextraction approach using auxiliary solvent: Determination of iodide in mineral water samples

A novel vortex-assisted liquid-liquid microextraction (VA-LLME) for determination of iodide was developed. The method includes the oxidation of iodide with iodate in the presence of hydrochloric acid followed by VA-LLME of the ion-pair formed between ICl2- and Astra Phloxine reagent (AP) and subsequent absorbance measurement at 555 nm. The appropriate experimental conditions were investigated and found to be: 5 mL of sample, 0.27 mol L-1 HCl, 0.027 mmol L-1 KIO3 as the oxidation agent, 250 mu L of extraction mixture containing amyl acetate as the extraction solvent and carbon tetrachloride as the auxiliary solvent (1:1, v/v), 0.04 mmol L-1 AP reagent, vortex time: 20 s at 3000 rpm, centrifugation: 4 min at 3000 rpm. The calibration plot was linear in the range 16.9-169 mu g L-1 of iodide, with a correlation coefficient (R-2) of 0.996, and the relative standard deviation ranged from 1.9 to 5.7%. The limit of detection (LOD) and limit of quantification (LOQ) were 1.75 and 6.01 mu g L-1 of iodide, respectively. The suggested procedure was applied for determination of iodide in real mineral water samples. (C) 2015 Elsevier B.V. All rights reserved.