Identification and Quantification of Thiaarenes in the Flue Gas of Lignite-Fired Domestic Heating

Abstract

Lignite briquettes with different sulfur contents were burned in a common type of domestic heating system. The levels of polycyclic aromatic sulfur heterocycles (PASH, thiaarenes) and their alkylated and phenylated derivatives in the flue gas were determined. The analytical method described comprises isokinetic sampling, GC/full scan-MS for screening analysis, HPLC/wavelength programmable fluorescence detection (selected PAHs used as internal standards for GC), GC/atomic emission detection or GC/pulsed flame photometric detection (sulfur-selective detection of thiaarenes), GC/high resolution MS (verification and quantification of thiaarenes), and the determination of the gas chromatographic retention indices. In total 57 thiaarene species (individual compounds if possible and groups of isomeric compounds such as alkylated/phenylated species) were identified, their retention indices determined, and quantified as flue gas emission concentrations. Not only thiophene-related thiaarenes but also species with two sulfur atoms in the molecule (e. g. thienothiophene derivatives) were found. The thiaarene emission pattern is discussed, as is the correlation between the thiaarene emissions and the sulfur content of the different briquette types burned.