Adsorptive-catalytic stripping measurements of ultratrace vanadium in the presence of cupferron and bromate.

An extremely sensitive stripping voltammetric procedure for ultratrace measurements of vanadium is reported. The method is based on the interfacial accumulation of the vanadium-cupferron complex onto the hanging mercury drop electrode, followed by the catalytic reduction of the adsorbed complex in the presence of bromate. The dual amplification effect associated with these accumulation and catalytic processes results in a detection limit of 4.9 x 10(-12)M (0.25 ppt). The relative standard deviation (at 50 ppt) is 1.6%. The procedure is also very selective. Such coupling of catalytic and adsorptive collection processes holds great promise for the development of an ultrasensitive voltammetric procedure for other trace metals.