Adsorptive stripping voltammetric determination of trace concentrations of molybdenum at an in situ plated lead film electrode.

An in situ plated lead film electrode has been applied for adsorptive stripping voltammetric determination of trace concentrations of molybdenum in the presence of Alizarin S. The procedure is based on the preconcentration of the molybdenum-Alizarin S complex at an in situ plated lead film electrode held at -0.6 V (versus Ag/AgCl), followed by a negatively sweeping square wave voltammetric scan. The peak current is proportional to the concentration of molybdenum over the range 2x10(-9) to 5x10(-8) mol L(-1), with a 3sigma detection limit of 9x10(-10) mol L(-1) with an accumulation time of 60 s. The measurements were carried out from underaerated solutions. The proposed procedure was validated in the course of Mo(VI) determination in water certified reference materials.