Catalytic-Spectrophotometric Determination of Trace Amounts of Iodide Based on Nuclear Fast Red-Iodate Reaction

Abstract

A sensitive catalytic-spectrophotometric method has been   developed for the determination of trace amounts of iodide   based on its effect on the reaction of nuclear fast red (NFR)   with iodate in acidic media. The reaction is followed spectrophotometrically   by measuring the change in absorbance of   NFR (ΔA) at 516 nm using a fixed time method (3.5 min).   The effect of different variables on the reaction was investigated   and optimum conditions were established. The calibration   graph was linear in the range of 7-70 ng mL^-1 (r = 0.9994). The   3S_b detection limit was 5.7 ng mL^-1 and the relative standard   deviation (RSD) for ten replicate measurements of 30 and 50   ng mL^-1 of iodide was 4.8 and 2.8 %, respectively. The method   was successfully applied to the determination of iodide in   table salt sample.