Evaluation of Methods Used to Desorb the Constituents Adsorbed on the Charcoal Contained in Automotive Evaporative Canisters. Part 1

摘要

The study evaluates current extraction methods for analyzing charcoal canisters which are used to control evaporative emissions in automobiles. The initial phase of the study investigated various extraction procedures and solvents, including carbon disulfide, methanol, cyclohexane, methylene chloride, and a mixture containing carbon disulfide and 12% acetone. The solvents were used in the soxhlet extraction of evaporative hydrocarbons adsorbed on the charcoal of the canister. In another procedure the charcoal was subjected to ultrasonication with carbon disulfide as the extraction solvent. The various sample extracts were analyzed for detailed hydrocarbon by gas chromatography and results of the procedures were compared. The difference between the results of the soxhlet extractions in the study and those in the previous study was that there had been a significant increase in the quantity of aromatics measured. The differences in the procedures for sample introduction into the GC was determined to result in fewer measurable hydrocarbons in the prior study.