LI Mei1, DONG Jun-Guo1, HUANG Zheng-Xu1, LI Lei1, GAO Wei1, NIAN Hui-Qing2, FU Zhong1,2,CHENG Ping1, ZHOU Zhen1

　　Key Words:

　　Single particle aerosol mass spectrometer; On-line and real time detection; Cigarette; Smoke aerosol

　　Abstract:

　　Single particle aerosol mass spectrometer (SPAMS) is an advanced instrument for simultaneous detection of aerodynamic size and chemical composition of individual aerosol particles in real time. In this study, the principle, configuration and features of our newly independent R&D SPAMS were described. Its application on the study of cigarette smoke aerosol analysis was also discussed. Aerodynamic focusing lens and double beam particle sizing system of the SPAMS were used to measure the aerodynamic diameter of particles. The laser ionization system realizes the accurate ionization of particles, and bipolar grid-reflection time-of-flight mass analyzer realizes the simultaneous detection of positive and negative ions. The results indicate that the fresh cigarette smoke particles have a relatively broader size distribution than that of aged smoke, and, in the aged smoke, the fraction of particles containing CN– nitrate, sulfate and ammonium all increased compared with fresh smoke; in contrast, the fraction of containing chloride reduced. The results can be explained by the translation of gas phase to particle phase as well as the heterogeneous reactions between the gas and particles. The reason for the reduction of chloride may be due to the heterogeneous reactions between HNO3 and chloride.