摘要
采用氢化物发生原子荧光法测定海南白沙绿茶和红茶中的硒含量,研究了仪器条件和还原剂等对硒原子荧光强度的影响。结果表明,最佳仪器条件为光电倍增管负高压300 V,灯电流80 mA;还原剂浓度为1.5%,载流盐酸浓度5%。该方法线性范围0~10μg/L时,与荧光值线性关系好,回归方程为y=75.949x-8.795 4,相关系数r=0.9998。方法检出限是0.024μg/kg,测定标准物质中硒的回收率为97.7%~109.6%。以国家标准物质茶叶(GBW10016)为监控样品,标准物质茶叶测定值与标准值吻合。白沙绿茶和红茶硒元素含量分别是34.4和20.1μg/kg。该方法线性范围宽、灵敏度高、检出限低,可用于茶叶等样品中硒元素含量的准确测定。
In this study the content of selenium in Baisha green and red tea were determined by hydride generation atomic fluorescence spectrometry. The influence factor such as instrument conditions and the concentration of reducing agent were considered. The results showed that the best instrument conditions were the photomultiplier negative pressure 300V, lamp current 80mA; the concentration of reducing agent1.5%, the concentration of hydrochloric acid current carrying 5%. The fluorescence values were good in the method when the linear range was 0 ~ 10μg/L, regression equation was y =75.949x-8.795 4,correlation coefficient, r=0.999 8, the detection limit was 0.024 μg/kg, and the recovery of method was97.7% ~ 109.6%. This method was verified by analyzing the national reference material(GBW10016) and the found value was in good agreement with the certified value. The content of selenium in Baisha green and red tea was 0.0772 μg/kg and 0.0456 μg/kg. The method has wide linear range, high sensitivity, low detection limit, which was very suitable for the determination of trace selenium of tea in general laboratory.
引文
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