CHEMI-LUMINESCENCE DETECTOR BASED ON ACTIVE NITROGEN FOR GAS-CHROMATOGRAPHY OF HYDROCARBONS

A sensitive detector for hydrocarbons has been demonstrated on the basis of the spectrophotometry determination of the intensity of the CN(B2Σ+→Σ22+) emission that results from the introduction of the sample into active nitrogen. The most intense spectroscopic feature of the CN flame is the Δv = 0 sequence at 383 to 388 nm. Both saturated and unsaturated samples, with or without halogen constituents, are detectable by monitoring the same feature. A minimum detectable limit of 100 pg has been demonstrated for vinyl fluoride. The introduction of HCI gas into the active nitrogen flow catalyzes the production of CN ultraviolet emission. The sensitivity to simple alkanes is generally improved by the addition of HCI. Methane, for example, was detected in this manner. Spectral evidence indicates the method can be made specific to compounds that contain metal atoms by monitoring atomic lines and CN emission simultaneously. The specificity of the method to other classes of species, such as oxygen-containing compounds, is discussed. © 1979, American Chemical Society. All rights reserved.