Potassium iodate purity determination by high precision coulometric titration: New measurement procedure implementation

A modified measurement procedure for the purity determination of high purity potassium iodate is described. The procedure consists of the coulometric standardization of sodium thiosulfate by generated iodine, stoichiometric interaction of standardized sodium thiosulfate with potassium iodate and the coulometric titration of excess sodium thiosulfate by generated iodine. In the proposed measurement procedure a previously unused method of simultaneous reagents adding (potassium iodate and sodium thiosulfate solution) into a coulometric cell is implemented. A relative expanded uncertainty for the potassium iodate purity determination 0.011% (k = 2) has been achieved.