The accurate measurement of the total nonmethane volatile organic carbon emissions from stationary sources is critical to characterizing of many industrial processes and for regulating according to the Clean Air Act. Current methods are difficult to use and the ability to do performance audits has been marginal, especially at low concentrations (50 parts per million of carbon, ppmc). One of the key elements for an ideal measurement technique would be a detector that responds to all classes of organic compounds equally, based on the number of carbon atoms present. A commercially available catalytic flame ionization detector (CFID) has shown promise in this area. Laboratory studies with a CFID were performed to determine the response of compounds with various functional groups. These classes included brominated, chlorinated, nitrogenated, oxygenated, aromatic, and nonaromatic compounds. The response of each compound is compared to the response of an alkane with the same number of carbon atoms. The paper will discuss this phase of the experimental work. Future work with the detector will incorporate an approach for sampling, sample recovery, and field tests for comparison to the EPA Method 25.