Evaluation of some dry ashing methods for anodic stripping voltammetric determination of cadmium and lead in biological materials

Several dry-ashing methods were evaluated for the accurate determination of cadmium and lead in biological materials by anodic stripping voltammetry. The method utilizing sulphuric acid as the ashing aid at 500°C was found to be most suitable for the determination of both elements. However, a carbonaceous residue still required that substantial sample dilution be made after dissolution of the sample ash to avoid interferences to the stripping electrode process(es). The dissolution of the sample ash with hydrochloric acid as preferred to the use of nitric acid in obtaining more reproducible results.