A Sensitive Method For Iodate Determination As A Function Of Chloride By Spectrophotometry

Gadde Ramachandraiah, Surendra

Abstract

A simple spectrophotometric method has been developed for the determination of IO3  as a function of Cl in 0.1% KI - 0.16 NH2SO4 medium. The calibration graphs for IO3  estimation in 0.1% KI - 0.16 NH2SO4 medium in various %Cl are determined by following the bands at 288 and 351 nm. The influence of Cl on the determination of IO3  is studied and an empirical equation involving the %Cl for IO3  estimation is proposed. At %Cl = 0, the lower detection limits for IO3  are 0.01 M at both wavelengths while the upper determination limits are 40 M and 60 M at 288 nm and 351 nm, respectively. In chloride medium, both the lower and upper limit increases with the increase in Cl concentration. At 6%Cl, the lower limit 1 M at both wavelengths while the upper detection limit increased to 80 and 100M, respectively, at 288 and 351 nm. The relative standard deviation found in five repetitive experiments are 0.74 and 1.45% at 288 nm band and 1.01 and 1.87% at 351 nm in Cl free, and 3.03 and 0.91% at 288 and 351 nm, respectively in 6 % Cl medium. The effect of K+, Ca2+ and Mg2+ commonly present in most edible salts, on the absorption intensities are reported.