Congener-specific detection of dioxins using jet-REMPI

Although 210 chemically different polychlorinated dibenzo-p-dioxin and dibe nzofuran congeners can be produced during combustion, it is currently belie ved that fewer than 20 are toxic enough to warrant monitoring. SRI is devel oping a continuous emissions monitor to study the emission levels of these most toxic dioxins, leading eventually to an improved understanding of the formation of these molecules and to improved means of monitoring and contro l. We report here the first results of performing congener-specific detecti on for two dichloro dibenzo-p-dioxins present in low ppt concentrations in a mixture using the supersonic jet/resonantly enhanced multiphoton ionizati on time-of-flight mass spectrometer technique. In addition, we present prel iminary data on the detection of chlorinated aromatic compounds using a two -color REMPI scheme with the same instrument. (C) 2001 Elsevier Science Ltd . All rights reserved.