Emission spectra obtained from the combustion of organic compounds in hydrogen flames

Abstract

A study is presented of the emission spectra produced by nebulisation of organic liquids into a nitrogen-hydrogen diffusion flame burning in air, and into a laminar-flow pre-mixed air-hydrogen flame. Both flames exhibit low background emissions and that of the diffusion flame is particularly low even over the OH-band region. Carbon, hydrogen and oxygen-containing compounds exhibit intense bands for CH, CHO, C₂ and OH species. Nitrogen-containing organic compounds additionally display NH, NO and CN bands; chlorine-containing compounds give CCl bands in the diffusion flame; sulphur compounds give CS and S₂ bands; and phosphorus compounds give HPO and PO bands.

The spectral distribution of these bands and their intensities indicate that many types of organic compound can be characterised and identified by direct observation of their emission spectra during combustion in these cool flames.