ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRIC DETERMINATION OF ALUMINUM, CADMIUM, CHROMIUM, COPPER, IRON, MANGANESE, NICKEL AND LEAD IN OLIVE OIL

A simple and fast procedure for the direct ETAAS determination of Al, Cd, Cr, Cu, Fe, Mn, Ni and Pb in olive oil is proposed, N,N-Hexamethyl enedithiocarbamic acid, hexamethyleneammonium salt (HMDC-HMA), was use d as a universal modifier with two functions: isoformation of the chem ical species of the investigated elements, present in olive oil and th eir thermal stabilisation during the pre-treatment step, Various organ ic solvents were studied and 1,4-dioxane was found to be the most suit able solvent for oil dilution prior to ETAAS analysis, 1,4-Dioxane imp roves the decomposition of triglycerides during the pre-treatment step and permits aqueous standard solutions to be used for calibration, Un coated graphite tubes with platforms are proposed as atomisers for the ETAAS determination of Cd, Cu, Fe, Mn and Fe, and pyrolytic graphite coated graphite tubes with grooves are the most suitable atomisers for Al, Cr and Ni, Instrumental parameters optimised according to pre-tre atment and atomisation curves, obtained in the presence of the olive o il matrix and with HMDC-HMA as modifier, are presented, The proposed m ethod permits the determination of 0.1 mu g g(-1) Fe, 0.05 mu g g(-1) Ni, 0.02 mu g g(-1) Al, Cu, Cr and Pb, and 0.01 mu g g(-1) Cd and Mn w ith relative standard deviations of about 8-10% for all analytes in th is concentration range.