Determination of Cd and Pb in phosphorites and phosphate fertilizers by means of a portable voltammetric analyzer based on 'Virtual Instrumentation'

摘要

This works reports the determination of cadmium and lead in phosphorite rocks and phosphate fertilizers by means of a portable voltammetric analyzer based on the "virtual instrumentation" principle. The analyzer consists of a home-made potentiostat, a conventional three-electrode cell and a magnetic stirrer interfaced to a PC with control and data acquisition software developed in LabVIEW 7.1. The apparatus operates in the square-wave anodic stripping voltammetry (SWASV) detection mode and utilizes wax-impregnated graphite working electrodes covered in-situ with a thin film of mercury. The phosphorite and fertilizer samples were subjected to pre-treatment with concentrated acid before the analysis. Different acids were accessed and compared in terms of sensitivity and background characteristics. Comparison of the results obtained by SWASV and atomic absorption spectrometry (AAS) indicates that no statistical difference exists between the two techniques.