Use of 3-D plots to avoid mutual interference in bianalyte ASV determinations: application to cadmium and lead detection.

We have examined the anodic stripping voltammetry (ASV) of Cd and Pb at carbon screen printed electrodes modified by an in situ deposited Bi film, and have demonstrated significant cross talk between the stripping peaks of the two metals. A simple and generally applicable method for dealing with this problem is described, based on curve-fitting three-dimensional calibration plots using MATLAB. Non-linear fitting to the calibrations produced coefficients of determination R(2)>0.99 for both metals. We have illustrated use of the plots in conjunction with Bi-plated electrodes by measuring 15 randomly selected mixtures of Cd and Pb of known concentration.