Detection of formyl radicals in low pressure methane + oxygen flames

Abstract

A three stage molecular beam inlet system into a quadrupole mass spectrometer has been constructed and used to study a range of low pressure methane + oxygen flames. The formyl radical has been positively identified as an intermediate species formed within the primary reaction zone. This was accomplished by comparing the mass spectra obtained from normal methane flames with those obtained from identical fully deuterated methane flames. The instrument has been calibrated for the mass discrimination effect and this allows an estimation of the formyl radical concentration.