采用黄原酯棉柱分离-氢化物发生-原子荧光光谱法测定大米中的镉和铅的含量。大米样品采用硝酸-高氯酸(4+1)混合酸消解,以5 mL·min-1流量经黄原酯棉柱吸附分离后,用氢化物发生-原子荧光光谱法进行测定。镉和铅的质量浓度均在一定的范围内与其荧光强度呈线性关系,镉和铅的检出限(3s/k)依次为0.85,4.5 μg·kg-1。对5 μg·L-1的镉、铅混合标准溶液连续测定11次,两者测定值的相对标准偏差依次为1.5%,2.3%。方法用于大米样品分析,加标回收率在94.0%~105%之间。

HG-AFS was applied to the determination of cadmium and lead in rice by separation on xanthate cotton fiber column. The rice sample was digested with mixed acid of nitric acid and perchloric acid (4+1), and the solution was separated by adsorption on xanthate cotton fiber column with flow rate of 5 mL·min-1. The contents of the 2 metal ions were determined by HG-AFS. Linear relationships between values of fluorescence intensity and mass concentration of Cd2+ and Pb2+ were kept in definite ranges, with detection limits (3s/k) of 0.85 μg·kg-1 of 4.5 μg·kg-1 respectively. Precision of the method was tested with mixed standard solution at the concentration level of 5 μg·L-1, values of RSD′s (n=11) found were 1.5% for cadmium and 2.3% for lead. The proposed method was applied to the analysis of substantial rice samples, giving values of recovery in the range of 94.0%-105%.