A COMPARISON OF FLAME IONIZATION AND OZONE CHEMILUMINESCENCE FOR THE DETERMINATION OF ATMOSPHERIC HYDROCARBONS

A reactive hydrocarbon analyzer has been constructed on the basis of c hemiluminescence reaction with ozone. This detector is designed to ope rate at varying temperatures which take advantage of the different rat es of reaction of the hydrocarbon classes with ozone to yield a measur e of their atmospheric reactivity. When operated at high temperatures (170 degrees C), all hydrocarbons will give a chemiluminescence signal . Reported here is a direct comparison of the ozone chemiluminescent d etector (operated at a temperature of 170 degrees C) with a flame ioni zation detector. This comparison was accomplished by connecting a capi llary gas chromatograph to each of the two detectors by means of a swi tching valve. Twenty-seven compounds representing alkanes, alkenes, ar omatics, and oxygenated hydrocarbons (aldehydes, ketones, alcohols, an d ethers) were studied. For the compounds studied, analytical sensitiv ities were 10-1000 times better for the chemiluminescence detector. Th e results of this comparison indicate that the response of the chemilu minescent detector at 170 degrees C correlates with a total carbon det ector (flame ionization detection) and that total response is a measur e of total carbon in the sample. The chemiluminescent system will be v ery useful for gas chromatographic detection of atmospheric hydrocarbo ns, particularly of oxygenates in complex mixtures. (C) 1998 Elsevier Science Ltd. All rights reserved.