固体悬浮液进样石墨炉原子吸收法测定茶叶中的微量镉

探讨了固体悬浮液进样石墨炉原子吸收光谱法测定镉时的最佳分析条件,建立了茶叶中微量镉的石墨炉原子吸收光谱直接测定方法。采用琼脂溶液与悬浮剂将茶叶样品均匀、稳定地悬浮于琼脂溶胶中,由自动进样器直接将茶叶悬浮液注入石墨炉中,使用基体改进技术,石墨炉原子吸收法测定茶叶中的镉,省去了以往冗长、繁琐的样品化学前处理过程。在优化的条件下,本法测定镉的检出限为0.065μg/L,相对标准偏差小于5%,线性范围为0～10μg/L,标准样品测试回收率为94%～106%,方法简便、快速、准确,用本法测定茶叶(85601)标准样品,测定结果与标准标准值一致。

Direct Determination of Trace Cadmium in Tea Using Suspension Sample Introduction by Graphite Furnace AtomicAbsorption Spectrometry

The various test conditions and effect factors for determination of cadmium were discussed and a method for thedirect determination of cadmium tee samples by using graphite furnace atomic absorption spectrometry with solid suspensionsampling was developed. Agar sol is used as a suspending agent. Ground and sieved sample is suspended homogeneously in the0.15% agar sol and injected into the graphite furnace by an autosampler, and cadmium in the samples are determined directly byusing matrix modifier techniques without chemical treatment. Thus, the tedious chemical pretreatment is omitted. The detectionlimit for cadmium was 0.065μg/L under optimum conditions. The linear range was 0～10μg/L. The relative standard deviationwas less than 5% and the recoveries of cadmium in tea standard samples were 94%～106%. The results show that the methodis accurate, simple, rapid with no interference. It has been applied to the determination of tea standard sample with satisfactoryresults.