建立了X射线近边吸收光谱法(1sXANES)测定大气颗粒物中无机氯和有机氯形态及含量的分析方法及质量控制体系。在储存环能量为1.5 GeV和光子能量为2.82 keV条件下,利用束流强度在300~150 mA的同步辐射光激发分析无机氯、链烃代有机氯和芳香烃代有机氯标准样品以及≤0.2μm的大气颗粒物样品。通过对标准品谱图的拟合计算,得到该方法无机氯、链烃代有机氯和芳香烃代有机氯最低检出限,分别为5.4,8.7和1.7μg/g。对已知无机氯和有机氯浓度的试样检出率均达到或接近95%,重复测定3-氯丙酸标准品(n=6),得到本方法的相对标准偏差(RSD)为0.9%。应用本方法可以实现定量无损地测定微量样品中氯的形态和含量,对城市大气颗粒物中氯的测定发现,颗粒物中无机氯和芳香烃代有机氯含量分别为110和12 ng/m3,链烃代氯的含量低于检出限。应用本方法对北京某地区大气颗粒物中氯元素形态进行测定,确定氯的主要存在形式是无机氯和芳香烃氯。
An analytical method of X-ray absorption near edge spectrometry(1sXANES) including the quality control for chlorine species in the atmospheric particles was established.The inorganic and aromatic and aliphatic chlorine in the standard and ≤0.2 atmospheric particle samples were analyzed under the conditions of 300-350 synchrotron radiation light beam intensity,storage ring energy of 1.5 GeV and photon energy of 2.82 keV.Calculated by fitting standard spectra,the method detection limits of inorganic,aliphatic and aromatic chlorine were 5.4,8.7 and 1.7 μg/g,respectively.The detectable frequency of atmospheric particle samples was almost 95%.The relative standard deviation(RSD) of repeated measurements of 3-chloro acid standard was 0.9%(n=6).The method was successfully applied to analyze the urban atmospheric particles non-destructively.The contents of inorganic chlorine,aromatic hydrocarbon-substituded organic chlorine in atmospheric ultra-fine particles(≤0.2 μm) were 110 and 12 ng/m^3,respectively,while the chain hydrocarbon substituted organic chlorine was not detected.The developed method was applied to the determination of chlorine species concentration in the atmospheric particles.The results showed that the main chlorine species in one place of Beijing were inorganic chlorine and aromatic chlorine.