利用气溶胶激光飞行时间质谱仪激光解吸电离技术开展了苯水相二次有机气溶胶在线测量研究。实验结果表明, 苯水相光氧化反应形成的二次有机气溶胶粒子粒径小于1.0μm, 激光解吸电离质谱中存在醛类m/z 29(CHO+)、57(CHOCO+), 羧酸m/z 44(COO+), 苯环m/z 77(C6H+5)、65(C5H+5)和酚类化合物m/z 93(C6H5O+)特征裂解碎片峰。醛类、羧酸和酚类化合物是苯水相SOA粒子的化学组分,各类型组分含量大小关系为: 醛类化合＞羧酸＞酚类化合物。气溶胶激光飞行时间质谱仪激光解吸电离技术能够用于水相SOA粒子化学组分的在线测量, 可用于水相SOA形成机理和过程的研究。

The on-line measurement of secondary organic aerosol formed from aqueous photooxidation of benzene with the laser desorption ionization technology of aerosol laser time-of-flight mass spectrometer was carried out. The experimental results indicated that the diameter of secondary organic aerosol particles formed from the aqueous photooxidation of benzene is less than 1.0 μm. Characteristic fragmentation peaks of aldehydes of m/z 29 (CHO+), 57 (CHOCO+), carboxylic acid of m/z 44 (COO+), benzene ring of m/z 77 (C6H+5), 65 (C5H+5) and phenolic compounds of m/z 93(C6H5O+)were found in laser desorption mass spectra of secondary organic aerosol particles. Experimental results demonstrate that aldehydes, carboxylic acids and phenolic compounds are the chemical components of secondary organic aerosol particles, and the contents of various components were: aldehydes ＞ carboxylic acids ＞ phenolic compounds. These were shown that the laser desorption ionization technology of aerosol laser time-of-flight mass spectrometer can be used for on-line measurement of chemical composition of aqueous secondary organic aerosol particles, is a useful tool to reveal the formation mechanism and process of aqueous secondary organic aerosol particles.