A method for the determination of zinc (Il) in lubricant oils by stripping
chronopotentiometry is described. The only necessary sample pretreatment was the
extraction of zinc (II) from the corresponding alkyl derivatives by hot concentrated
hydrochloric acid in a suitable extractor. The metal ions were concentrated as the
corresponding metals on a glassy carbon working electrode and then stripped by a
suitable oxidant. Quantitative analysis was carried out by the method of standard
additions; a good linearity was obtained in the range of concentrations examined.
Recoveries of 94 % were obtained from a lubricant oil spiked at different levels. The
detection limit was 0.02 mg g-1 and the coefficient of variation (mean of nine
deterrninations) was 5.2%. Results obtained on commercial lubricant oils were not
significantly different from those obtained by atomic absorption spectrometry.
