Sensitive adsorptive stripping voltammetric method for direct determination of trace concentration of lead in the presence of cupferron in natural water samples

This paper reports the use of an adsorptive voltammetric technique for Pb(II) determination using cupferron as a selective complexing agent. After accumulation of the complex onto a hanging mercury drop electrode, the electrode potential was scanned with differential pulse modulation and the reduction current of lead was observed at about-0.5V. Under optimum conditions (5x10(-4)molL(-1) cupferron concentration, 0.1molL(-1) acetate buffer (pH 5.5), adsorption at-50mV for 30s) the detection limit was 5.1x10(-10)molL(-1). The relative standard deviation of five measurements for low lead concentration was 3.1%. The accuracy of the method was tested by analysing certified reference material (SPS-WW1 Waste Water). Finally, the method was successfully applied to the determination of Pb(II) in river water samples without any pretreatments.