Ion formation in hydrocarbon flames

Abstract

While it is generally accepted that ions arise in hydrocarbon flames by the CH—O mechanism, the only indication that this is the sole mechanism is the equal per carbon response of most hydrocarbons in the flame ionization detector. This response feature can equally be attributed to other flame processes and does not apply to C2H2 in any case. Comparison of rates of ion formation with CH and As emission intensities indicates that C2H2 and CH4 give abnormal rates of ion formation which can be explained on the basis of one or more additional mechanisms of ion formation.