Catalytic-adsorptive stripping voltammetric determination of molybdenum in plant foodstuffs

In acetate buffer solution (pH 3.5) containing oxine and chlorate, ultratrace amounts of molybdenum can be determined after adsorptive accumulation of the Mo(VI)-oxine complex on a hanging mercury drop electrode, coupled with the catalytic effect on the reduction of chlorate. Under optimized conditions, the catalytic-adsorptive stripping voltammetric procedure gives excellent selectivity and an extremely low detection limit of 1.7 pM molybdenum (60 s accumulation). The stripping peak current increases linearly with molybdenum concentration between 10 pM and 5.0 nM. The procedure is applied to determine traces of molybdenum in plant foodstuffs.