用X射线吸收近边结构谱研究大气颗粒物中元素的种态

大气颗粒物中元素的种态研究，对评价其毒性和污染来源等有很重要的意义。本工作采集了不同地点和不同粒径的大气颗粒物样品，测定了样品中铬、锰、铜和锌的X射线吸收近边结构(XANES)谱，利用该谱分析了这些元素在颗粒物中的种态。结果显示，所采集的样品中铬主要以三价形式存在，锰主要以二价形式存在，铜也以二价形式存在，而锌主要以硫酸盐存在。用质子激发X射线荧光(PIXE)法测定了这些元素在样品中的浓度，观察到不同采样点和不同粒径的颗粒物中金属含量的差别，但未看到种态的这种变化。

Study on elemental speciation in airborne particulate matter by XANES

The study on elemental speciation in airborne particulate matter (PM) is important for its evaluation of toxicity and source of pollution. In the present work, samples of airborne PM were collected in different site and with different size, and the X-ray absorption near-edge structure (XANES) spectra of Cr, Mn, Cu and Zn were measured. The oxidation state of these elements and possible chemical speciation are discussed using the spectra The results show that in our samples, the oxidation state of Cr is likely tervalent, Mn exists mainly as divalence, Cu also exists as divalence and Zn exists mainly as sulfate. The elemental concentrations in the samples were determined by proton induced X-ray emission (PIXE), The difference in concentrations was observed for samples from different site and with different size, but obvious difference in speciation was not found.