Salting-out homogeneous liquid-liquid microextraction for the spectrophotometric determination of iodate in food grade salt

Publication date: Available online 27 December 2019Source: Journal of Food Composition and AnalysisAuthor(s): Manju Gupta, Anjali DsouzaAbstractA simple and rapid method has been reported for the determination of iodate in food grade salt samples where iodate has been used for the oxidation of phenylhydrazine to phenyldiazonium ion which then couples with 2-naphthol or with 8-hydroxyquinoline to produce orange red azo dye. The dye was extracted with microliter volume of 2-propanol, when the phase separation occurred by addition of ammonium sulphate, a process called salting out homogeneous liquid liquid microextraction (SH-LLME), and analysed spectrophotometrically. Relative efficiencies of both the coupling reagents were compared for iodate determination, when both coupling agents, 8-hydroxyquinoline and 2-naphthol, produced relatively comparable results. The method has been optimized for the reaction time, and type of extracting solvent and salt for phase separation. A linear calibration curve was obtained for 0.08-10 mg L-1 of iodate with correlation coefficient of 0.998 and limit of detection of 16 µg L-1. Food grade salt samples have been analyzed with adequate recovery in spiking experiments, being, 86.2-114.6 (RSD, 6.6-12.6%) and 90.8-111.3 (RSD, 7.1-12.6%) using 2-naphthol and 8-hydroxyquinoline as a coupler, respectively. The SH-LLME avoids pH adjustment of the final test sample before extraction, and Cu(II) and Fe(III) up to 1 and 6 mg L-1, respectively, ...
Source: Journal of Food Composition and Analysis - Category: Food Science Source Type: research