Flow injection amperometry for the determination of iodate in iodized table salt

A very simple flow injection amperometric system for determination of iodate has been developed. Cyclic voltammetry was used to study reactions of iodate, iodide and iodine on a glassy carbon electrode. A single line manifold of the dow system consists of a pulse-free reagent propulsion using a simple Mariotte bottle, a home-made injection valve, and a cross flow electrochemical cell with a potentiostat for control a potential of glassy carbon working electrode at +200 mV versus Ag/AgCl electrode. Using a solution of 1.0% w/v NaCl, 0.02% w/v KI and 0.1 M HCl as a reagent and a flow rate of 2 ml/min, a linear calibration up to 25 mg/l IO3- with a detection limit of 0.5 mg/l IO3- was obtained. Relative standard deviation for 10 injections of 10 mg/l IO3- solution was 1.7%. A sample throughput of 35 injections per hour was achieved. The system was successfully applied for determination of iodate in iodized table salts, validating by the AOAC titrimetric method. (C) 2001 Elsevier Science B.V. All rights reserved.