TIME-RESOLVED TRACE ANALYSIS OF EXHAUST-GAS BY MEANS OF LASER MASS-SPECTROMETRY

The large number of components and their very different and rapidly va rying concentrations complicates the analysis of exhaust gases of comb ustion engines. Here, a new analytical technique, based on the combina tion of resonance enhanced multiphoton ionization, performed by pulsed tunable lasers, and time of flight mass spectrometry is presented. It allows the simultaneous detection of several trace components with co ncentrations ranging from 1 ppm up to several percent with a quantitat ive accuracy better than 10%. Time resolution of 10 ms could be achiev ed with this system. A preliminary list of substances detectable by th is technique contains 25 substances; some of them belong to the strong est compounds inducing ozone formation.