Determination of Trace Lead and Zinc in Beers by Atomic Absorption Spectrometry after Wet Digestion

In this paper,flame atomic absorption spectrometry and graphite furnace atomic absorption spectrometry were employed for Zn and Pb determination in beers after wet digestion.Instrument conditions of atomic absorption spectrometry were optimized and the optimal experimental conditions were selected.The effects of the type of mixed acid,the volume of digesting solution and digestion temperature were investigated.The complete digestion was performed using 16 mL of HNO3 and 4 mL of HClO4 at 200 ℃.The relative standard deviations(RSDs) of the flame atomic absorption spectrometry and graphite furnace atomic absorption spectrometry were 0.92% and 1.8%,respectively,and the recovery obtained for Pb and Zn were 99.8% and 96.5%,respectively.The methods showed linear relationship at 0-80 μg/L and 0-1.50 μg/mL for Pb and Zn,respectively.And the detection limit of Pb and Zn were 0.2 μg/L and 8.0 μg/L,respectively.The proposed method has the advantages of low detection limit,good precision and accuracy.It is suited for the determination of Pb and Zn concentrations in beers.The contents of Pb and Zn were 11.34-47.15 μg/L and 277-422 μg/L,respectively in nine kinds of beer samples from Nanchang City market.