Abstract
The method uses a maximum absorbance appeared in the oxidation reaction of 2×10-3 M chlorpromazine with 0.6 M hydrogen peroxide in 4 M phosphoric acid medium by the catalytic action iodide ion. It allows the determination of iodide down to 0.06ng/ ml (0.3 ng in reaction solution 5 ml) and has the advantages of little influence from reactant concentrations and reaction temperature, and also low interference from iron ion. The linear range of the calibration curve is 0-5ml iodide with a standard deviation of 0.02ng/ ml Iron ion up to 300ng/ ml and many other do not interfere with the determination, expect a few ions such as vanadium over 20ng/ ml, thiocyanate over 10ng/ ml, etc. This method can also be applied to the determination of iodate and periodate ions in the same manner. The contents of iodine in rain and snow collected in Kofu at time was relatively lower compared with those in the literature cited, and decreased with the elapsed time of rain and snow falls.
