The microdetermination of dissolved oxygen in water. III titrimetric determination of iodine in sub‐microgramme amounts

Abstract

Abstract A sensitive electrical circuit is described for use with all‐platinum or tungsten/platinum electrodes in the amperometric titration of iodine. The procedure described is sensitive to 0·01 μg. of iodine in 100 ml. of solution. The presence of up to at least 2 p.p.m. of ferrous, ferric and cupric ions causes no interference. Thiosulphate and iodate solutions of concentration 10 −5N can be accurately prepared by successive dilution of 0·1N solutions. Titration of 100 ml. of 10 −7 N‐thiosulphate with 10 −5 N‐iodate is reproducible and practicable.