AN ACCURATE METHOD OF IODOMETRIC TITRATION FOR DETERMINING OXYGEN-CONTENT OF SUPERCONDUCTING CUPRATES

There are three problems existing in double iodometric titration. Firs t, the calculating equation is too rough to obtain accurate results. S econd, an error comes from iodine adsorbed by CuI. Third, when a sampl e is doped with iron-like elements, iron interferes with this method. The above problems were solved as following. We adopted a new equation , which may modify copper valence p by 4% and oxygen content by 0.02. To reduce the experimental error KSCN was added to displace the adsorb ed iodine on the CuI. NH4HF2 was introduced to prevent the interferenc e of Fe. Our experiment results show that by adding NH4HF2 the modific ation of oxygen content increases when Fe content increases.