Titrimetric determination of thiocyanate and thiosulphate ions by oxidation with iodine in alkaline solution

Thiocyanate (2.7-90 mug) and thiosulphate (4.5-90 mug) ions are oxidized by iodine in alkaline media to sulphate ions. After acidification, the excess of iodine is extracted into chloroform, and the iodide ions formed in the redox reaction subjected to an amplification reaction. Either a titrimetric or a spectrophotometric finish may be used. Each thiocyanate and thiosulphate ion results in the ultimate production of 19 and 24 iodine molecules, respectively.