微波消解—AAS法测定食品中铅、镉、铁、锰、铜和锌及其不确定度评估

Microwave-Assisted Digestion with Atomic Absorption Spectrometry for Determination of Pb,Cd,Cu,Fe,Zn and Mn in Food and Assessment of Uncertainty of Analytical Results

应用微波消解溶样,原子吸收光谱法测定食品中多种元素,其中,使用石墨炉法测定铅和镉,火焰法测定铁、锰、铜和锌,并对原子吸收光谱法分析结果的不确定度作了评估。实验结果表明,铅、镉、铁、锰、铜、锌分别在5~40,0.25~3.0μg.L^-1,0.20~3.0,0.10~2.0,0.10~2.0和0.05~1.0μg.mL^-1范围内有良好的线性关系,其线性相关系数均在0.999 8以上,用标样GBW 07602（GSV-1）测定,其相对误差均在允许范围内。可见用微波溶样,AAS法同时测定食品中多种元素,具有快速、简便、节省试剂、消解完全、污染少等特点,测定结果的精密度和准确度令人满意。

An AAS method for the determination of trace amount of Pb, Cd, Cu, Fe, Mn and Zn in food was established, and the uncertainty of the analytical results was assessed in the present paper. Microwave-assisted digestion technigue was used to prevent the elements from volatile losses and to reduce the blank. Fe, Mn, Cu and Zn were determined by flame AAS, and Pb and Cd were determined by using graphite furnace AAS. A National Standard Material GBW 07602（GSV-1） was analyzed and the results were in accordance with the certificate values, verifying the accuracy and the precision of the proposed method. The uncertainty of the analytical results was assessed on the basis of the requirements of the ISO documents. Uncertainty sources from all procedures were evaluated.