Deveopment of PIXE for Small Biological Samples and Its Application to Study for Mechanism of Accumulation of Trace Elements

为了制备少量生物材料的辐照靶，必须有一层薄薄的支撑膜。我们开发了一种制备高质量支撑膜的简单技术。该聚乙烯醇（PVF）薄膜厚度为0.1 mm，均匀性好。光谱的连续x射线制作背景小于传统10mm美拉膜的1/20。我们计算了理论检出限，并观测到3MeV回旋加速器对多种元素的检出限<1ng。（文献1,2,4）<200mug生物材料的支撑膜采用PVF膜。通过对生物标准材料的分析，评估了PVF薄膜的pxie分析的可靠性。利用PVF pxie对盐渍蒿等小型甲壳类动物进行了元素丰度测定。在人工海水中养殖盐蒿，描述了元素丰度随大小和繁殖期的变化特征。（文献3）在人工海水中也饲养了来自太平洋的硅藻如Pheodictylum sp.，并利用pxie对小型Pheodictylum sp.中的元素丰度进行了调查。通过多元素分析，观察了土壤中微量元素尤其是锌的富集行为。无机元素的分析方法有很多种，但大多不适合生物材料的定量分析。生物和环境科学常常需要同时测定液体和凝胶样品中的微量元素。然而，传统的分析方法需要对样品进行预处理，如冷冻干燥、湿消解等。由于不需要预处理，立式空气PIXE是原位分析的有力工具。我们计划安装一种新的立式空气中PIXE，并讨论了液体和薄膜靶中多种元素的检出限。(参考5)

A thin support film is indispensable to make irradiation targets of a small amount of biological material for trace anlyasis by PIXE.We developed a simple technique for the preparation of high quality support film. The thickness of this polyvinylformarl (PVF) film was 0.1 mm with good homogeneity. The continuous X-ray making background of spectrum was <1/20 that of conventional 10mm Maylar film. We calculated theoretical detection limits and also observed <1ng detection limits for many kinds of elements by 3MeV protons from a cyclotron. (Reference 1,2,4) The PVF film was applied for the support film for <200mug of biological materials. The reliability of the PIXE analysis using the PVF film was evaluated by analysis for biological standart materials. The elemental abundance in the small Crustacea such as Artemia salina was surveyed by the PVF PIXE.artemia salina was bred in artificial sea water and the characteristic of elemental abundance as a function of size and breeding day was described. (Reference 3) Diatom such as Pheodictylum sp. from Pacific Ocean was also bred in artificial sea water and the elemental abundance in the small Pheodictylum sp.was surveyed by PIXE.Accumulation behavior of trace elements especially for zinc was observed by multielemental analysis by PIXE.Many kinds of analytical methods for determination of inorganic elements are available, however, most of them are not suitable for in sutu analysis of biological materials. Biological and environmental science ofter require simultaneous determination of trace elements inliquid and gel samples. However, conventional analytical methodns require pretreatment of samples such as freeze drying, wet digestion, etc. By constant, vertical type in-air PIXE is powerful tool for in situ analysis because of no pretreatment. We have planned to install a new vertical type in-air PIXE and discussed the detection limits for many kinds of elements in liquid and thin film target. (Reference 5)