STRIPPING VOLTAMMETRIC DETERMINATION OF HEAVY METALS IN VEGETABLE OILS
Abstract
The possibility of stripping-voltammetric determination of Zn, Cd, Pb, Cu, Hg trace amounts in vegetable oils without the use of mineralization procedure has been demonstrated. It has been established that high sensitivity of the method (<0.001 mg/dm>3) can be achieved for Zn, Cd, Pb, Cu by cathodic accumulation on the surface of the amalgamated silver indicator electrode, and by the accumulation of mercury on the electrode containing 58 % Au, 34 % Cu, 8% Ag. The amount of the deposited metal has been determined by the magnitude of the anodic current in an aqueous-acetone electrolyte containing formic (Zn, Cd, Pb, Cu) or sulfuric (Hg) acid additives. Analysis of twelve refined and unrefined vegetable oil samples (sunflower, olive, linseed, rapeseed, and corn) showed the presence of trace impurities of zinc (0.6–9.6 mg/dm3), lead (0.02–0.09 mg/dm3), and copper (0.02–0.17 mg/dm3). Additional traces of mercury (0.002–0.009 mg/dm3) were detected in eight oil samples and cadmium traces (0.02–0.05 mg/dm3) in nine samples. In general, the content of toxic metals in the samples does not exceed the permissible levels governed by technical regulations.
About the Authors
N. P. Matveiko
Belarusian State Economic University
Belarus
Belarus
D. Sc. (Chemistry), Pro- fessor, Head of the Department
A. I. Kulak
Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belarus
Belarus
Belarus
Cor. Member, D. Sc. (Chemi- stry), Professor, Director
S. K. Protasov
Belarusian State Economic University
Belarus
Belarus
Ph. D. (Technology), Associate Professor
V. V. Sadowski
Belarusian State Economic University
Belarus
Belarus
D. Sc. (Technology), Professor, Vice-Rector
References
1. Aparicio R., Harwood J., “Handbook of olive oil”, Analysis and properties, 2nd ed., Springer, New York, US, 2013, pp. 497–498, doi: 10.1007/978-1-4614-7777-8.
2. Choe E., Min D. B., “Mechanisms and factors for edible oil oxidation”, Comprehensive reviews in food science and food safety, 2006, vol. 5, no. 4, pp. 169–186, doi: 10.1111/j.1541-4337.2006.00009.x.
3. Bendini A., Cerretani L., Vecchi S., Carrasco-Pancorbo A., Lercker G., “Protective effects of extra virgin olive oil phenolics on oxidative stability in the presence or absence of copper ions”, Journal of Agricultural and Food Chemistry, 2006, vol. 54, no. 13, pp. 4880–4887, doi: 10.1021/jf060481r.
4. Lepri F. G., Chaves E. S., Vieira M. A., Ribeiro A. S., Curtius A. J., DeOliveira L. C., DeCampos R. C., “Determination of trace elements in vegetable oils and biodiesel by atomic spectrometric techniques–a review”, Applied Spectroscopy Reviews, 2011, vol. 46, no. 3, pp. 175–206, doi: 10.1080/05704928.2010.529628.
5. Mendil D., Uluözlü Ö. D., Tüzen M., Soylak M., “Investigation of the levels of some element in edible oil samples produced in Turkey by atomic absorption spectrometry”, Journal of Hazardous Materials, 2009, vol. 165, no. 1, pp. 724–728, doi: 10.1016/j.jhazmat.2008.10.046.
6. Raptis, S. E., Kaiser, G., Tölg, G., “The decomposition of oils and fats in a stream of oxygen for the determination of trace elements”, Analytica Chimica Acta, 1982, vol. 138, pp. 93–101, doi: 10.1016/S0003-2670(01)85291-0.
7. Castillo J. R., Jiménez M. S., Ebdon L., “Semiquantitative simultaneous determination of metals in olive oil using direct emulsion nebulization”, Journal of Analytical Atomic Spectrometry, 1999, vol. 14, no. 9, pp. 1515–1518, doi: 10.1039/ A900754G.
8. Llorent-Martínez E. J., Ortega-Barrales P., Fernández-de Córdova M. L., Domínguez-Vidal A. R. M. A., Ruiz-Medina A., “Investigation by ICP-MS of trace element levels in vegetable edible oils produced in Spain”, Food Chemistry, 2011, vol. 127, no. 3, pp. 1257–1262, doi: 10.1016/j.foodchem.2011.01.064.
9. Buldini, P. L., Ferri, D., Sharma, J. L., “Determination of some inorganic species in edible vegetable oils and fats by ion chromatography”, Journal of Chromatography A, 1997, vol. 789, no. 1, pp. 549–555, doi: 10.1016/S0021-9673(97)00822-4.
10. Coco F. L., Ceccon L., Ciraolo L., Novelli V., “Determination of cadmium (II) and zinc (II) in olive oils by derivative potentiometric stripping analysis”, Food Control, 2003, vol. 14, no. 1, pp. 55–59, doi: 10.1016/S0956-7135(02)00054-3.
11. Dugo G., La Pera L., La Torre G. L., Giuffrida D., “Determination of Cd (II), Cu (II), Pb (II), and Zn (II) content in commercial vegetable oils using derivative potentiometric stripping analysis”, Food Chemistry, 2004, vol. 87, no. 4, pp. 639– 645, doi: 10.1016/j.foodchem.2003.12.035.
12. La Pera L., Lo Curto S., Visco A., La Torre L., Dugo G., “Derivative potentiometric stripping analysis (dPSA) used for the determination of cadmium, copper, lead, and zinc in Sicilian olive oils”, Journal of agricultural and food chemistry, 2002, vol. 50, no. 11, pp. 3090–3093, doi: 10.1021/jf0113124.
13. Díaz T. G., Guiberteau A., Soto M. L., Ortiz J. M., “Determination of copper with 5, 5-dimethylcyclohexane-1, 2, 3-trione 1, 2-dioxime 3-thiosemicarbazone in olive oils by adsorptive stripping square wave voltammetry”, Food Chemistry, 2006, vol. 96, no. 1, pp. 156–162, doi: 10.1016/j.foodchem.2005.04.014.
14. Abbasi Sh., Allahyari M., Taherimaslak Z., Nematollahi D., Abbasi F., “New determination of lead in edible oil and water samples by high selective adsorptive stripping voltammetry with SPADNS”, International Journal of Electrochemical Science, 2009, vol. 4, pp. 602–613.
15. Wahdat F., Hinkel S., Neeb R., “Direct inverse voltammetric determination of Pb, Cu and Cd in some edible oils after solubilization”, Fresenius’ journal of analytical chemistry, 1995, vol. 352, no. 3-4, pp. 393–394, doi: 10.1007/BF00322240.
Review
Views: 485
Email this article 