Catalytic Spectrophotometric Determination of Trace Amounts of Iron (III) Based on Methyl Violet - Periodate Reaction Using 1,10-phenanthroline as an Activator

摘要

Iron (III) catalyses the oxidation of methyl violet with sodium periodate in acetate buffer. It was found that 1,10-phenanthroline acts as an activator in the reaction and the rate of the reaction is increased further. The catalytic effect of iron (III) and activating effect of 1,10-phenanthroline was used to develop a kinetic method for the determination of iron (III). The reaction was monitored spectrophotometrically by measuring the change in absorbance at 585 nm using a fixed time method (4 min). The effect of variables was studied and optimum conditions were established. The calibration curve was linear in the range of 2-20 ng mL~(-1) of iron (III) and limit of detection based on 3S_b was 0.86 ng mL~(-1). The relative standard deviation for ten replicate measurements of 4 and 10 ng mL~(-1) of iron was 5.0 and 4.2 %, respectively. The method was successfully applied to the determination of iron in a drug formulation and water samples.