Abstract
A rapid and simple analytical method of low molecular dicarboxylic acids and levoglucosan in PM2.5 by in-situ silylation thermal desorption GC/MS has been developed. The optimum thermal desorption conditions for the derivatization were as follows: the primary desorption temperature : 320 ℃, helium flow: 20 mL/min, the reaction time: 10 min, and the amount of the reagent (BSTFA+TMCS(99:1) :pyridine 9:1): 10μL. Standard recovery tests using PM2.5 samples showed that an excess amount of the samples caused deterioration of the peak shapes of the derivatives. The sample amount of PM2.5 should be limited. Nonpolar compounds; i. e., n-alkanes, hopane, and PAHs, can be analyzed by the same system, although a bsimultaneous analysis is difficult due to the deference in the appropriate sample amount. Application of this method to PM2.5 ambient samples in Tokyo showed that the composition of the organic matters was different between summer and winter and the composition of the n-alkanes may be varied due to emissions from different sources. This method may be an effective tool for the investigation of organic aerosols.
