DETERMINATION OF LEAD AND ARSENIC IN WINES BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

Methods for the determination of As and Pb in wines by electrothermal atomic absorption spectrometry (ETAAS) are proposed. For As, 8 ml of wine were diluted with 1 ml of nitric acid in a PTFE bomb, followed by heating to 150-degrees-C for 90 min. The transparent solution obtained was diluted to 10 ml with de-ionized water. The integrated absorbances of the solutions were measured by ETAAS using 5 mug of Pd, as a chemical modifier. For Pb, the integrated absorbances were measured after diluting the wine sample, 1 + 4, with 0.2% nitric acid, using a mixture of 10 mug of Pd and 15 mug of Mg as modifier. The detection limits (k = 3) were 6.6 and 15.5 ng ml-1 for As and Pb, respectively, 20-30 times below the maximum limits proposed by the control agencies. Three wine samples were analysed and the concentrations found were below the maximum permissible concentrations. Recoveries were approximately 100%, for analytical solutions containing 10% v/v and 0.2% v/v of nitric acid, for As and Pb, respectively. No interference was observed.