Use of voltammetric methods for the analysis of trace metals in engine oils

Abstract

Accurate and convenient analytical procedures have been developed for the trace determination of metal ions in unused engine oil using advanced voltammetric methods viz. direct current polarography (DCP), differential pulse polarography (DPP) and differential pulse anodic stripping voltammetry (DPASY). The analysis has been carried out after ashing the samples and converting it to aqueous solution. Trace metals have been determined at different <i>p</i>H values in 0.1<i>M</i> (NH₄)₂ tartrate, 0.1<i>M</i> KCl and 0.01M EDTA as supporting electrolyte with 0.001% gelatin as a maximum suppressor. The results reveal that Cr, Pb, Cd, Zn, Co, Fe and Cu are present in the sample in significant amounts. The observed voltammetric results have been compared with those obtained using AAS. Statistical treatment of the observed voltammetric data reveal high accuracy and good precision of determination.