摘要
试验采用原子荧光法通过测定硒的含量建立绞股蓝茶中硒含量的测定方法并评定测量不确定度。优化结果为负高压270 V、灯电流(主灯电流、辅灯电流设定值相同)45 mA、载气流速400 mL/min、屏蔽气流速600 mL/min、载液为5%(V/V)的HCl-H_(2)O溶液、还原剂为10 g硼氰化钾/L(5 g/L KOH-H_(2)O溶液)溶液。在该条件下,硒在0~5 ng/mL的范围内,浓度和荧光值线性关系良好R^(2)=0.9994,检出限为0.07956μg/L,相对标准偏差RSD范围为0.60%~1.74%,加标回收率范围为93.45%~99.98%。通过对不确定度来源的分析和计算,原子荧光法测定绞股蓝茶中硒含量为(0.083±0.003)mg/kg;k=2。结果表明该方法高效、准确、重现性好,适合绞股蓝茶中硒元素含量测定,评定结果为质量控制提供了科学依据,对生产过程及绞股蓝茶质量安全监测具有一定指导意义。
In this experiment,the content of selenium in Gynostemma pentaphyllum tea was determined by atomic fluorescence spectrometry,the method for the determination of selenium was established and its uncertainty was evaluated.The optimized analysis conditions were as follows:negative high voltage 270 V,lamp current 45 mA,flow rate of carrier gas 400 mL/min,flow rate of shield gas 600 mL/min,concentration of carrier fluid 5%(V/V)HCl-H_(2)O,concentration of reductant 10 g KBH4/1 L(5 g/L KOH-H_(2)O).Under this condition,the linear relationship between the concentration of selenium and the fluorescence value was good in the range of 0~5 ng/ml,R^(2)=0.9994,the detection limit was 0.07956μg/L,the relative standard deviation(RSD)ranged from 0.60%to 1.74%,and the recovery rate ranged from 93.45%to 99.98%.Through the analysis and calculation of the sources of uncertainty,the content of selenium in gynostemma pentaphyllum tea determined by atomic fluorescence spectrometry was(0.083±0.003)mg/Kg;k=2.The results showed that this method was efficient,accurate and repeatable,and suitable for the determination of selenium in gynostemma pentaphyllum tea.The evaluation results provided a scientific basis for quality control,and had a certain guiding significance for the production process control and the quality and safety monitoring of gynostemma pentaphyllum tea.
作者
景文祥
喻莉
刘欢
余英
JING Wenxiang;YU Li;LIU Huan;YU Ying(Yibin Academy of Foresty&Sciences,Yibin 644000,China;School of Materials Science and Engineering,Southwest University of Science and Technology,Mianyang 621000,China;China Power Sichuan Fuxi Power Development Company Ltd.,Yibin 645100,China;Sichuan will testing Technology Co.,Ltd.,Chengdu 610041,China)
出处
《茶叶通讯》
2021年第2期319-327,共9页
Journal of Tea Communication
基金
宜宾市科技计划(重点)项目(2016ZNY005)
四川省林产品质量安全监测项目(2019-JC-10、2020-JC-10、2021-JC-10)
四川省科技计划项目(2019YFN0029)。
关键词
绞股蓝茶
硒
原子荧光法
不确定度
Gynostemma pentaphyllum tea
Selenium
Atomic fluorescence spectrometry
Uncertainty
