Differential pulse cathodic stripping adsorption voltammetric determination of trace amounts of lead using factorial design for optimization.

A sensitive cathodic stripping voltammetric method is developed for determination of lead(II), with adsorptive collection of complexes with Pyrogallol red (PGR) on to a hanging mercury drop electrode. After accumulation of the complex at -0.80 V vs. Ag/AgCl reference electrode, the potential is scanned in a negative direction from -0.20 to -0.50 V with differential pulse method. Then the reduction peak current for the lead(II)-PGR complex is measured at -0.39 V. The influence of reagent and instrumental variables was completely studied by factorial design analysis. The optimum analytical conditions for the determination of lead(II) were established. Under optimum conditions, lead(II) determined in the range of 0.1-30.0 ng ml(-1) with a limit of detection of 0.06 ng ml(-1). The method is successfully applied to determination of lead(II) in water sample.