A mobile and modular single particle laser desorption/ionisation time of flight mass spectrometer for analysis of combustion aerosols at incineration plants

摘要

A recent study (Zimmermann et al.,2003) showed that the analysis of combustion aerosols from an wood incineration plant sampled on a filter by FT-LMMS (Fourier Transform-Laser Microprobe Mass Spectrometry) and by A-TOFMS (Aerosol -Time Of-Flight Mass Spectrometry) permits to differentiate chemically the aerosol samples according to their respective sampling site in the combustion chamber.Nevertheless the sampling of particles on filters modifies de facto the characteristics of the collected particles so that observed characteristics do not correspond to the native or sampling characteristics of the particle.To have a "near-real" characterization of the aerosol population,analysis should be performed on an on-line and single-particle basis.On-line measurements provide the composition of the particle at its sampling time and site.Thus single particle analysis permits to know if chemicals are internally or externally mixed in particles and if its chemical composition is size-dependant.These informations permit to better trace particles in the burning chamber and to better understand their formation conditions and processes.In this focus,the laser based aerosol mass spectrometer technique is a well suited tool.An aerosol laser desorption/ionization time-of-flight mass spectrometer,which meets specific requirements for its operation in industrial plants was built up at the GSF-Forschungszentrum.Characteristics of the instrument and first results are presented here.