该研究应用能量色散X射线荧光光谱分析技术(energy dispersive X-ray fluorescence,EDXRF)对茶叶中重金属进行检测。先对茶叶样品进行一系列的粉碎、过筛、压片等前处理过程,然后进入EDXRF荧光光谱仪进行检测,以计数率为检测指标,对仪器检测时间、样品颗粒粒径、样品颗粒紧实度、样品厚度这4个实验条件进行优化,并将最优条件运用于不同类型茶叶的检测。结果表明,将4 g过140目筛的茶叶粉末样品,在25 MPa压力下压片30 s后制成片状,在仪器检测时间为90 s时,所测得的计数率最高。该条件下的精密度和稳定性分别为0.03%和0.19%,说明该方法精密度和稳定性都比较高。
This paper aims to establish energy dispersive X-ray fluorescence spectrometry for tea. Firstly, a series of pre-treatment processes such as crushing, sifting and tablet pressing were carried out on the tea sample. Then they were entered into the EDXRF fluorescence spectrometer for detection. In the process of the experiment, the four experimental conditions of the instrument detection time, particle size, compactness, and thickness were optimized. The counting rate was taken as the detection index, and the optimal conditions were applied to the detection of different types of tea leaves. The results showed that 4 g sample of tea powder pass 140 mesh screen were made into sheets under 25 MPa pressure for 30 s, and the highest counting rate was measured when the detection time was 90 s. The precision and stability of this method are 0.03% and 0.19% respectively, which indicates that the precision and stability of this method are relatively high.
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