Development of X-ray fluorescence analysis of light elements in biological samples --- application to the study of Alzheimer disease

我们构造了一个新的X射线荧光室，用于全反射分析和二维X射线荧光分析。该仪器适用于生物样品的微量元素分析，如活检样品（TR-XRF）和具有复杂结构的癌症组织（XRF成像）。来自同步辐射和常规X射线管的X射线可用作X射线源。我们已经使用该仪器测定生物样品中的铝水平，如下所示。通过对样品制备技术、内标和测量条件的考察，建立了同步辐射诱导全反射X射线荧光分析生物样品中铝的方法。样品为铝的标准溶液和染铝大鼠的脏器。样品在氧气流中加热，用浓硝酸和过氧化氢分解。考虑到Cr的能量、共存元素和样品制备的简单性，选择Cr作为内标。在空气中用7.25keV X射线可测定10 ng范围的铝。

We have constructed a new X-ray fluorescence chamber for total reflection analysis and two-dimensional X-ray fluoresce analysis. This instrument is suitable for trace element analysis of biological samples such as biopsy samples (TR-XRF) and cancer tissues with complex structure (XRF imaging). X-rays from Synchrotron radiation and conventional X-ray tube can be used as the X-ray source. We have used this instrument to determine Al level in biological samples as given below. We have also determined the Zen and Cu levels from biopsy samples.Synchrotron radiation Induced total reflection X-ray fluorescence analysis of Al in biological samples was developed through examinations of sample preparation technique, internal standard and measurement conditions. The samples were standard solutions of Al and organs of Al administrated rat. The sample was heated in a current of oxygen gas and decomposed with concentrated nitric acid and hydrogen peroxide. Cr was chosen as an internal standard after consideration of its energy, coexisting elements in the sample and simplicity of the sample preparation. It was possible to determine Al of 10ng range using 7.25keV X-ray in air.