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

• A vortex-assisted liquid–liquid microextraction approach using an auxiliary solvent.
• An inexpensive, widely available UV–Vis detection technique.
• Determination of iodide in real 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 μL 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 μg L−1 of iodide, with a correlation coefficient (R2) 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 μg L−1 of iodide, respectively. The suggested procedure was applied for determination of iodide in real mineral water samples.

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