Determination of lead in table wines by graphite furnace atomic absorption spectrometry

A quick, easy method was developed for the analysis of table wines for lead quantitated at > or = 14 ng Pb/mL wine. The method uses graphite furnace atomic absorption spectrometry with Zeeman background correction and a L'vov pyrolytic graphite platform. Ammonium dihydrogen phosphate is used as a matrix modifier. Wines are diluted by a factor of 10 with 1% HNO3 and analyzed directly. Their absorbances are compared with those of a standard curve prepared with 1% HNO3. Analytical results obtained by comparison with a standard curve agreed with those obtained by the method of standard additions. Four white, 4 red, and 2 rosé wines were studied. Pb concentrations varied from 15 to 135 ng Pb/mL. Wines fortified with 100 ng Pb/mL had an average recovery of 94%. The average short-term relative standard deviation (RSD) was 2.1%; the average long-term RSD was 7.4%. The estimated detection (3 sigma) and quantitation (10 sigma) limits were 4 and 14 ng Pb/mL, respectively.