A pencil-lead bismuth film electrode and chemometric tools for simultaneous determination of heavy metals in propolis samples

A simultaneous determination of Zn, Cd, Pb and Cu in raw propolis samples, employing square wave anodic stripping voltammetry and chemometric tools, was developed. For this purpose, a pencil-lead bismuth film electrode was used as a working electrode. In order to optimize the parameters of square wave voltammetry a Box-Behnken design combined with desirability function was used. Different algorithms such Asymmetric Least Squares (AsLS) and Correlation Optimized Warping (COW) were employed in order to preprocess the raw data. Partial Least Squares (PLS) and Artificial Neuron Networks (ANN) were used to predict the concentration of the four metals in the samples. The method was tested successfully on raw propolis samples obtained from different localities of the Province of Buenos Aires, Argentina and the results were validated with recovery assays.