Sampling and Analysis Experiments for Improved Characterization of Products of Incomplete Combustion

Abstract

Laboratory and field experiments were conducted to evaluate the volatile organic sampling train (VOST) methodology for the sampling and analysis of products of incomplete combustion (PICs). A pilot-scale incinerator was used to incinerate several volatile chlorinated organic compounds which were known to produce PICs. Approximately 300 ppm of 1,2-dichloroethane, 1,1,1-trichloroethane, and trichloroethene were individually incinerated at 700°C. Standard VOST sampling apparatus was used to collect samples for determinations of precision and for distributive volume-studies. A series of experiments was conducted to establish whether PICs were being formed at concentration levels which could be measured by the VOST methodology. Samples were collected at 1 L/ min for 20 min with standard pairs of Tenax-Tenax/charcoal cartridges. The major PICs found were vinyl chloride from 1,2-dichloroethane, 1,1-dlchloroethene from 1,1,1-trichloroethane, and carbon tetrachloride from trichloroethene. Chloromethane was also formed at significant levels for all of the compounds incinerated. Additional field samples that were collected and analyzed showed that the precision of the PIC generation was fairly constant. Use of a wide-bore (0.53 mm) capillary column, to improve chromatographic resolution, was also evaluated. This modification was used to enhance the gas chromatography/mass spectrometry performance and allow improved identification of compounds in the field samples. An Environmental Protection Agency audit cylinder containing compounds at approximately 5 ppb was also sampled and analyzed. Results showed these procedures incorporating VOST methodology were accurate and precise.