Determination of zinc (II) in lubricant oils by stripping chronopotentiometry

摘要

A method for the determination of zinc (Il) in lubricant oils by strippingchronopotentiometry is described. The only necessary sample pretreatment was theextraction of zinc (II) from the corresponding alkyl derivatives by hot concentratedhydrochloric acid in a suitable extractor. The metal ions were concentrated as thecorresponding metals on a glassy carbon working electrode and then stripped by asuitable oxidant. Quantitative analysis was carried out by the method of standardadditions; a good linearity was obtained in the range of concentrations examined.Recoveries of 94 % were obtained from a lubricant oil spiked at different levels. Thedetection limit was 0.02 mg g-1 and the coefficient of variation (mean of ninedeterrninations) was 5.2%. Results obtained on commercial lubricant oils were notsignificantly different from those obtained by atomic absorption spectrometry.