ANALYSIS OF LEAD AND ZINC BY MERCURY-FREE POTENTIOMETRIC STRIPPING ANALYSIS

A method is presented for trace-element analysis of lead and zinc by p otentiometric stripping analysis (PSA) where both the glassy-carbon wo rking electrode and the electrolyte are free of mercury. Analysis of z inc requires an activation of the glassy-carbon electrode. The activat ion is performed by preconcentrating zinc on glassy carbon at -1400 mV (SCE) in a mercury-free electrolyte containing 0.1 M HCl and 2 ppm Zn2 +, followed by stripping at approx. -1050 mV. A linear relationship be tween stripping peak areas, recorded in the derivative mode, and conce ntration was found in the range 0-2000 ppb.