Accuracy analysis on concentration determination of molecular iodine in gamma irradiated solutions

The gamma irradiated aqueous samples containing I2 and I− were measured by two different analysis methods using an UV–VIS spectrophotometer. One is the I2 concentration was determined by using the equilibrium relationship between I3− and I−. The other is I2 concentration was measured after extracted by toluene. In the I2 and total I measurements, both methods were confirmed to have an accuracy within 4%. The I2 concentrations measured by the toluene extraction method were always lower for the identical samples than those measured by the equilibrium relationship method. This was understood as a loss occurring in the toluene extraction step.