Abstract

The need for a continuous emissions monitor for the determination of dioxins and furans at realistic (ppt or sub-ppt) concentrations in real time (minutes) is widely recognized in the waste combustion community. The key issues are overall sensitivity, and selectivity among the many congeners found in real applications. At SRI International we have begun a project designed to meet these needs. Our instrument is based on supersonic jet expansion and cooling, followed by resonantly enhanced multiphoton ionization (REMPI) into a mass spectrometer. This furnishes the dual selectivity of tuned laser absorption and mass analysis. We have made direct measurements of several polychlorinated dioxins and furans using a one-color REMPI scheme, and we have demonstrated a two-color excitation scheme.

© 2000 Optical Society of America