DETERMINATION OF INDIVIDUAL HYDROCARBONS IN AUTOMOBILE EXHAUST FROM GASOLINE-FUELED, METHANOL-FUELED AND VARIABLE-FUELED VEHICLES

A method was developed for determining individual hydrocarbon (HC) emissions from gasoline-, methanol- and variable-fueled vehicles. The exhaust samples are collected in Tedlar® bags, and a portion of the sample is injected into a gas chromatograph, equipped with a DB-1 60 m × 0.32 mm I.D. (1.0 μm) fused-silica column. Methanol was well resolved from the gasoline HC species and did not interfere in the analysis. Validation, stability and intercomparison studies for total HC are also reported in this paper. In addition, an impinger-gas chromatography (GC) technique for determining unburned methanol emissions is also described. The detection limits of the GC methods for individual HCs and methanol was about 50 and 250 parts per billion (109) C, respectively. This corresponds to a vehicular mass emission rate of 0.1 mg/mile HC and 1.3 mg/mile methanol, respectively, for the Federal Test Procedure emissions test. © 1990.