Determination of Lead with a Carbon Paste Electrode Modified with a Chelating Resin in Rainwater and Human Urine

A method is described for determination of lead using a carbon paste electrode modified wtih Dowex A-1 chelating ion-exchanger resin and cyclic voltammetry for the electrochemical measurement. The best conditions for preconcentration were found to be open circuit for 10 min in ammonium acetate, pH 5. Optima parameters for the stripping measurements were a HCl 0.1 M solution as supporting electrolyte, a delay time of 48s at -1.0 vs. S.C.E. and a scan rate of 150mv/s. The anodic peak at -0.52V vs. S.C.E. permits adequate quantification of lead in concentration between 4 and 200 ng/ml with a LD (3[sgrave]) of 1.2ng/ml. The method was used for determination of lead in rainwater and human urine.