顺序注射氢化物发生-原子荧光光谱法同时测定中药材中砷和镉

目的: 建立一种以顺序注射氢化物发生-原子荧光光谱法同时测定中药材中砷和镉含量的方法。 方法: 通过考察光电倍增管负高压、砷和镉灯电流、原子化器高度、载气流量、屏蔽气流量、增敏剂等因素对测定结果的的影响。在载流盐酸的浓度为0.6 mol·L^-1 ,KBH₄浓度为20 g·L^-1 ,增敏剂硫脲和钴离子的浓度分别为80 g·L^-1 和70 mg·L^-1 时,同时测定砷和镉的效果最佳。 结果: 在最佳实验条件下,砷和镉的检出限分别为0.014 μg·L^-1 和0.18 μg·L^-1 ,加标回收率为92.9%~103.5%,相对标准偏差小于3.2%,被测试样中共存的离子对砷和镉的测定没有干扰。 结论: 本方法操作方便、快速,用于中药材中砷和镉的同时测定,具有很好的可行性和实用性。

Objective: Method for simultaneous determination of arsenic and cadmium in Chinese herbal medicine by sequential injection hydride generation-atomic fluorescence spectrometry was established. Methods: The influence of instrument parameters such as the negative high voltage on the photomultiplier,current of lamp,carrier gas rate,shield gas rate,sensitizer on the determination of arsenic and cadmium were studied,the research has discovered when the concentration of hydrochloric acid and potassium borohydride were 0.6 mol·L^-1 and 20 g·L^-1 respectively,the concentration of sensitizer sulfocarbamide and Co²⁺ were 80 g·L^-1 and 70 mg·L^-1 respectively,the effect of determination of arsenic and cadmium was perfect. Results: Under the proposed conditions,the detection limits of arsenic and cadmium were 0.014 μg·L^-1 and 0.18 μg·L^-1 respectively.The standard addition recoveries for arsenic and cadmium were 92.9%-103.5%.The maximum RSD found was 3.2%.The coexistence ions in determined Chinese herbal medicine samples did almost not interfere in the determination of arsenic and cadmium. Conclusion: The operation is easy and its sensitivity is higher.There are feasibility and practicability to determine arsenic and cadmium in Chinese herbal medicine.