A highly sensitive spectrophotometric method for the determination of iodate using leuco xylene cyanol FF

A highly sensitive and selective spectophotometric method has been developed for the determination of iodate (IO3-) in table salt and sea water. The proposed method is based on the oxidation of leuco xylene cyanol FF (LXCFF) to its blue form of xylene cyanol FF by iodate in sulfuric acid medium, the absorbance of the dye is measured in an acetate buffer medium (pH 4.0) at 620 nm. Beer's law is obeyed in the range 0.4-14 mu g mL(-1)of iodate. The molar absorptivity, Sandell's sensitivity, detection limit and quantitation limit of the method were found to be 1.71 X 10(4) Lmol(-1) cm(-1), 1.02 x 10(-2) mu g cm(-2), 0.026 mu g mL(-1) and 0.0806 mu g mL(-1) respectively. The optimum reaction conditions and other analytical conditions were evaluated. The effect of interfering ions on the determination is described. The proposed method has been successfully applied to the determination of the iodate in the table salt and sea water.