A simple, rapid and sensitive spectrophotometric method has been developed for the determination of periodate in solution and river water samples. The method is based on the reaction of periodate with iodide in an acid medium to liberate iodine. This liberated iodine bleaches the violet color of the azure B and is measured at 644 nm. This decrease in absorbance is directly proportional to the periodate concentration and obeys Beer's law in the range of 0.2 - 5.5 µg mL-1. The molar absorptivity, Sandell's sensitivity, detection limit and quantitation limit of the method were found to be 1.09 X 10(5) L mol-1 cm-1 , 1.75 X10-3 µg cm-2, 0.07 µg mL-1 and 0.20 µg mL-1 respectively. The optimum reaction conditions and other analytical parameters were evaluated. The effect of interfering ions on the determination is described. The proposed method has been successfully applied to the determination of periodate in solutions and river water samples.
periodate determination; spectrophotometry; azure B
