Determination of iodate in table salt by transient isotachophoresis–capillary zone electrophoresis

A transient isotachophoresis–capillary zone electrophoresis (tITP–CZE) method was first time developed for determining iodate in table salt. Sensitivity enhancement was accomplished by coupling on-capillary tITP with CZE. The interference of sample matrix was overcome by using electrophoretic buffer containing high concentration of sodium chloride. The optimal terminating electrolyte for tITP was 1500 mmol/L phosphate and the separation buffer of capillary zone electrophoresis was 10 g/L sodium chloride (pH 8.0) containing 20 mmol/L cetyltrimethylammonium chloride (CTAC). Calibration graphs based on peak height and peak area showed good linearity. Use of chromate as the internal standard significantly improved the precision of the quantitative results. The wavelength of UV detection for iodate was set at 218 nm with the detection limits of 3.5 μg/L for iodate. The quantitative results of iodate in table salt measured by the tITP–CZE method were compared with those measured by the redox titration and there was no significant difference between the two means. The method developed was sensitive, fast and simple.