研究了用湿.法消解啤酒样品、石墨炉原子吸收光谱(GFAAS)及火焰原子吸收光谱(FAAS)法分别测定啤酒中的痕量Pb2+和Zn2+。对仪器的工作参数进行了优化,探讨了混合酸消解体系、消解液用量,消解温度等因素的影响。结果表明,在200。C温度下,HNO3+HClO4(16+4)混酸能完全消解样品。Pb计、Zn计分别在0~80μg/L、0~1.50μg/mL范围内线性关系良好(线性相关系数r分别为0.9995和0.9997),其检出限分别为0.2μg/L、8.0μg/L。测定Pb2+、Zn2+的相对标准偏差(RSD)分别为1.8%和0.92%,加标回收率分别为96.5%和99.8%。该方法检出限低,精密度和准确度高,适用于啤酒样品中痕量铅、锌含量的测定。检测的9种啤酒样品中铅、锌含量范围分别为11.34~47.15μg/L、277~422μg/L,低于食品中的限量值。
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 HN()3 and 4 mI. of HC104 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 0-80μg/L and 0-1.50μg/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. 15μg/L and 277-422μg/L,respectively in nine kinds of beer samples from Nanchang City market.