New measurements of resonance ionization detection limits are presented for seven species, of high thermal stability, which are potentially useful surrogates for continuous emission monitoring of incinerator effluent. Resonance ionization detection limit data are now available for 20 aliphatic and aromatic compounds; eight of these compounds have sub part-per-billion detection limits. These eight also exhibit selectivities exceeding 10 3 when detected in the presence of a "soup" of chemically similar interferant species likely to be present in stack gas samples. Preliminary measurements indicate that detection limits, obtained under ideal conditions in a helium carrier gas, are also approached under adverse sampling conditions tested with synthetic "soups". The implications of these measurements on the selection of surrogates and the prospects for repetitive on-line hazardous emissions monitoring are discussed

Continuous monitoring techniques are needed for assurance that the stack gases of hazardous and municipal waste incinerators do not emit unacceptable levels of dangerous compounds. The development of suitable on‐line “real‐time” monitors may help answer current public concerns regarding the safety of thermal processing methods and may simplify the permitting process for new facilities. Recent research is reviewed which suggests that resonance ionization mass spectrometry is capable of real‐time monitoring of wide classes of toxic molecules at the part‐per‐billion level against complex backgrounds of interferant species. Recent advances in laser technology promise to make on‐line repetitive multispecies monitoring of hazardous emissions a practical reality.

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Strong (1+2) resonance-enhanced multiphoton ionization (REMPI) spectra have been recorded for cyanogen resonantly excited by single photon absorption on vibronically allowed transitions to the Ã 1Σu− and B̃ 1Δu electronic states at wavelengths from 205 to 220 nm. A previously unreported Fermi resonance between the ν2 and 4ν5 vibrational modes of the à state is observed for the rotationally resolved spectra of transitions that involve excitations of the ν2 mode. New measurements of vibrational and rotational spectroscopic constants are reported for the à and B̃ electronic states. A detection limit of 120 ppb measured for (1+2) REMPI of cyanogen is an order of magnitude larger than typical (2+1) REMPI detection limits for other aliphatic compounds.