飞行时间二次离子质谱法在一次污染过程中PM2.5表面组分分析中的应用

团簇离子源的发明和使用,使飞行时间二次离子质谱(TOF-SIMS)法成为材料表面化学分析越来越重要的手段,TOF-SIMS法的主要测试功能包括表层质谱、化学成像及深度剖析3种。采用TOF-SIMS法对一次污染过程中的大气细颗粒物(PM_2.5)的表层进行检测,得到了PM_2.5表面成分的质谱及成像信息。结果表明:PM_2.5表层存在多种金属离子,通过扫描电子显微镜能谱仪的形貌与飞行时间二次离子质谱仪的成像亮度分析可知,K⁺、Na⁺、Mg²⁺响应强度相对较强,含量较高;通过原子吸收光谱仪进行金属离子定量可知,2018年11月4日和12月24日的K⁺、Na⁺、Mg²⁺的平均质量分别为1.809 5、0.443 8、1.526 2 mg;从形态分布上看,PM_2.5表面烟尘集合体含量较多,其次为燃煤飞灰、矿物颗粒和超细未知颗粒;PM_2.5表层的有机物离子C

Application of Time of Flight Secondary Ion Mass Spectrometry in the Analysis of PM2.5 Surface Components in the Process of Primary Pollution

The invention and use of cluster ion sources have made time-of-flight secondary ion mass spectrometry(TOF-SIMS) an increasingly important tool for surface chemical analysis of materials.The main testing functions of TOF-SIMS include surface mass spectrometry,chemical imaging and depth analysis.TOF-SIMS was used to detect the surface of atmospheric particulate matter(PM_2.5) in Qiqihar City.Mass spectrometry and imaging information of PM_2.5 surface components were obtained.The results show that there are many kinds of metal ions on the surface of PM_2.5,The response of K⁺,Na⁺,Mg²⁺ ions is strong through the analysis of morphology and imaging brightness of time-of-flight secondary ion mass spectrometer.Metal ions were quantitatively determined by atomic absorption spectrometry.The average contents of K⁺,Na⁺,Mg²⁺ in the two days were 1.809 5,0.443 8,1.526 2 mg,respectively.The degree of PM_2.5 is relatively strong and the content is relatively high.From the morphological distribution,the content of smoke and dust aggregates on PM_2.5 surface is higher,followed by coal-fired fly ash and mineral particles and ultrafine unknown particles;and there are more C_xH_y fragments of organic matter ions on PM_2.5 surface,which are further determined by the test data m/z,indicating that there are a lot of aliphatic hydrocarbons in the surface layer of PM_2.5 particles.And aromatic hydrocarbons;in addition,there are organic and inorganic compounds containing N,O,S,etc.