Determination of lead and arsenic in wines by electrothermal atomic absorption spectrometry

Abstract

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 °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 µg 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 µg of Pd and 15 µg 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.