OSCILLO-VOLTAMMETRIC DETERMINATION OF IODINE IN TABLE SALT SPIKED WITH POTASSIUM IODATE

In a medium of 0.2 mol·L-1 NaOH solution,two incisions at -0.6 V and -1.6 V(vs.SCE) a simple,on the cathodic branch of oscillopolarogram due to the presence of iodate were observed.Based on this fact,a simple second derivative oscillo-voltammetric method was established for the determination of iodine in table salt spiked with potassium iodate.It was shown by experimental results that the peak height of the incision at -1.6 V was linearly increased with iodate concentrations in range of 3.5×10-6-6.4×10-5mol·L-1.The regression equation was h(V)=141.40+1.03×106 c(mol·L-1),with a correlation coefficient of 0.999 1.Detection limit was 1.0×10-6mol·L-1.RSD (n=5) was 2.2% at the level of 5.0×10-6mol·L-1 of KIO3.This method has the characteristic of needing no complex instrument,ease in operation and unnecessary of removal of oxygen by blowing with nitrogen.