The Detection of Atoms and Free Radicals in Flames by Mass Spectrometric Techniques

摘要

A mass spectrometric method employing a molecular beam gas sampling system has been developed for the detection of atoms and radicals in chemical reactions. Background signals have been virtually eliminated by mechanically modulating the molecular beam and applying phase detection to the ion signal. The application of the method is illustrated by examples of lowhyphen;pressure flames. In the hydrogenhyphen;oxygen flame H, O, and OH have been positively identified. The mass spectrum of a simple hydrocarbon flame, such as the methanehyphen;oxygen flame, is complicated by the presence of a large number of stable components generated in the flame. In the methanehyphen;oxygen flame the stable intermediates include C2H2, CO, CH2O or C2H6, CH4O, and C4H2. The methyl radical has been clearly identified in the methanehyphen;oxygen flame. A search for the HO2radical in the hydrogenhyphen;oxygen flame was made without obtaining positive results. The HO2detection problem is discussed in detail.