Determination of Cd(II), Cu(II), Pb(II), and Zn(II) content in commercial vegetable oils using derivative potentiometric stripping analysis

• Published in: Food chemistry 2004-10, Vol.87 (4), p.639-645
• Main Authors: Dugo, Giacomo, La Pera, Lara, La Torre, Giovanna Loredana, Giuffrida, Daniele
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cadmium; Copper; Derivative potentiometric stripping analysis; Fat industries; Food industries; Fundamental and applied biological sciences. Psychology; Lead; Vegetable oils; Zinc
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2003.12.035

The purpose of this paper was to determine the content of Cd(II), Pb(II), Cu(II), and Zn(II) in commercial peanuts, sunflower, soy, maize, rice, grape-seed and hazelnut oils, using derivative potentiometric stripping analysis (dPSA). Previous reports provided evidence that hydrochloric acid extraction followed by dPSA was well suited for trace metals determination in oils: precision lower than 2.1% (expressed as relative standard deviation of the measurements) and detection limits ranging from 0.4 to 0.9 μg kg −1 were obtained for Cd(II), Cu(II), Pb(II), and Zn(II) in the studied vegetable oils. The optimised method was verified with analysing certified reference materials and the obtained accuracy ranged from 93.5% to 97.0%. The results obtained from analysis of commercial vegetable oils showed that the mean levels of cadmium were lower than 4.90 μg kg −1, the average content of lead ranged from 8.60 to 55.61 μg kg −1, the mean content of copper from 53.80 to 674.45 μg kg −1, and zinc from 51.45 to 555.61 μg kg −1.