Spectrophotometric Determination of Trace Amounts of Vanadium (V) by Means of Its Catalytic Effect on Oxidation of Azomethine-H by Bromate

摘要

A new selective and sensitive kinetic method for determination of trace amounts of vanadium (V) (0.5～40ng/ml) based on its catalytic effect on the oxidation of azomethine-H by bromate at pH 4.2 and 25℃ was reported and its reaction mechanism was studied. The reaction was monitored spectropho- tometrically by measuring the increase in absorbance of oxidation product of azomethine-H at 436 nm af- ter a fixed time (5 min). The detection limit of the method is down to 2.0×10~-10g/ml and the rel- ative standard deviation (RSD) for 30 ng/ml of V(V) is 0.26/100 (n=6). The effect of foreign ions on V (V) determination was also discussed, and the method is mostly free from interferenes of oth- er ions. The proposed method was successfully applied to the determination of trace amounts of vanadium in water samples.