Gan Ting-ting, Zhang Yu-jun, Zhao Nan-jing, Yin Gao-fang, Xiao Xue, Zhang Wei, Liu Jian-guo, Liu Wen-qing
Guang Pu Xue Yu Guang Pu Fen Xi. 2016 Dec;36(12):4039-44.
The mixed samples of nylon film enrichment of Cr, Pb and Cd three elements and glass fiber membrane filter were as the research object. With the method of superposition of membrane filter, the XRF spectra were measured under different thin film samples thicknesses. According the changes of characteristic XRF of Cr, Pb and Cd elements in the mixed sample and Ca, As and Sr elements in glass fiber membranes, the effects of sample thickness on thin film method XRF spectrum measurement were studied. The study results showed that the effects of thin film sample thickness on the fluorescent properties of elements with characteristic spectral lines in different energy ranges were different. The energy of characteristic spectral lines was greater, the loss of element characteristic X-ray fluorescence when it passed through membrane and reached detector was less. But matrix effect caused by thin film sample thickness increase was stronger with the energy of characteristic spectral lines greater. The background fluorescent intensity in corresponding characteristic spectral line location was greater. So the impact of matrix effect caused by sample thickness increase on thin film method XRF spectrum measurement sensitivity was greater. For elements with low energy characteristic spectral lines (energy≤7 keV), the way of increasing thin film sample thickness in order to increase the mass-thickness concentration of component measured, can not effectively improve the sensitivity of thin film method XRF spectrum measurement. And thin film samples thickness within 0.96 mm is conductive to the measurement and analysis of XRF spectrum. For element with higher energy characteristic spectra lines(energy＞7 keV), the sensitivity of XRF spectrum measurement can be appropriately increased by the way of increase thin film sample thickness in order to increase the mass-thickness concentration of component measured. And thin film samples thickness within 0.96～2.24 mm is more conductive to the measurement and analysis of XRF spectrum. The study provides an important theoretical basis for thin sample preparation and enrichment technology of thin film method X-ray fluorescence spectrum analysis the atmosphere and water heavy metal.
以尼龙膜富集Cr、Pb和Cd三种元素与玻璃纤维膜过滤的混合样品为研究对象。采用膜过滤叠加法，在不同薄膜样品厚度下测量XRF光谱。根据混合样品中Cr、Pb和Cd元素以及玻璃纤维膜中Ca、As和Sr元素的特征XRF变化，研究了样品厚度对薄膜法XRF光谱测量的影响。研究结果表明，薄膜样品厚度对不同能量范围内具有特征谱线的元素荧光特性的影响不同。特征谱线能量越大，元素特征X射线荧光透过薄膜到达探测器时的损失越小。但随着特征谱线能量增大，薄膜样品厚度增加引起的基体效应越强，相应特征谱线位置的背景荧光强度越大。因此，样品厚度增加引起的基体效应对薄膜法XRF光谱测量灵敏度的影响越大。对于低能量特征谱线（能量≤7 keV）的元素，通过增加薄膜样品厚度来提高被测组分的质量厚度浓度，不能有效提高薄膜法XRF光谱测量的灵敏度。且薄膜样品厚度在0.96 mm以内有利于XRF光谱的测量与分析。对于高能量特征谱线（能量＞7 keV）的元素，可通过增加薄膜样品厚度来提高被测组分的质量厚度浓度，适当提高XRF光谱测量的灵敏度。且薄膜样品厚度在0.96～2.24 mm范围内更有利于XRF光谱的测量与分析。该研究为大气和水体重金属薄膜法X射线荧光光谱分析的薄样品制备及富集技术提供了重要的理论依据。
