Determination of copper (II) and lead (II) in olive oils by derivated potentiometric stripping analysis

A method for the determination of copper (II) and lead (II) in olive oils by derivative potentiometric stripping analysis is described. The only necessary sample pretreatment is the extraction of copper (II) and lead (II) from the corresponding chemical species to which they may be linked by hot concentrated hydrochloric acid in a suitable extractor. Quantitative analysis was carried out by the method of standard additions. Recoveries of 90-94% for copper (II) and of 92-96% for lead (II) were obtained from an olive oil spiked at different levels. The detection limits were 1.4 ng g -1 for copper (II) and 1.8 ng g -1 for lead (II) and the relative standard deviations (mean of nine determinations) were 5.3 and 4.1%, respectively. Results obtained on commercial olive oils were not significantly different from those obtained by inductively coupled plasma mass spectrometry.