Ultrasensitive catalytic-adsorptive stripping voltammetric determination of molybdenum using a Mo(VI)-chloranilic acid-chlorate system

A catalytic adsorptive stripping voltammetric procedure of the determination of ultratrace amounts of molybdenum using a novel catalytic system, Mo(VI)-chloranilic acid-chlorate was elaborated. In a supporting electrolyte containing 0.01 M HCl (pH 2), 2.5 × 10−4 M chloranilic acid and 0.4 M KClO3, the catalytic adsorptive stripping response observed at −0.23 V was proportional to the Mo(VI) concentration within the range of 0.16 μgl−1 to 60 μgl−1 for 60 s of accumulation. The limit of detection was found to be 1.6 × 10−10 M. The reproducibility of the blank signal was equal to 4.8%. The method was validated by quantifying Mo(VI) in certified reference surface water, and it was applied for the determination of Mo(VI) in extracts of fly ashes. The possible scheme of the catalytic reaction was suggested.