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Central Coast Analytical Services, Inc. Analytical Method for the Accurate Determination of Organic Compounds in Air Abstract Central Coast Analytical Services (CCAS) has developed an analytical method for the accurate determination of atmospheric concentrations of non -methane organic compounds in ambient air and landfill gases. The method employs cryogenic trapping to isolate trace organic compounds from the sample followed by fused silica capillary column gas chromatography/ mass spectrometry. Certified Reference Standards traceable to NBS Standard Reference Materials (SRMs) and internal standards are used to insure the accuracy of the measurements. Experimental Method Air samples from Tedlar bags or electropolished stainless steel canisters are analyzed for toxic organic compounds with detection limits in the sub part -per -billion range. The analytical technique employs cryogenic trapping to isolate trace organic components in ambient air from major air components such as oxygen and nitrogen. An evacuated reservoir of known volume is used to pull air from a sample bag (Tedlar) or electropolished stainless steel canister through a sample loop which is immersed in liquid argon (-186 C). The sample loop is packed with 60/80 mesh inert glass beads to provide a large surface area for condensation of the organics. A vacuum gauge attached to the reservoir is used to measure the pressure drop caused by transfer of the sample from the sample container to the reservoir. Since the volume of the reservoir is accurately known, the amount of air drawn through the sample loop can be calculated. Approximately 500 mL of sample is drawn through the sample loop at a rate of 25-50 mL/min. Since atmospheric water vapor will also condense at the liquid argon temperatures, and because this water can cause problems with the subsequent GC/MS analysis, a Nafion dryer is placed between the sample and the cryogenic sample loop. Nafion is an inert material selectively Central Air, Water, & Hazardous Waste Sampling, Analysis, & Consultation State Certified Hazardous Waste, Chemistry, & Bacteriology Laboratories the sample passes through the Nafion Coast Analytical Services 141 Suburban Road, Suite C-4 6483-D Calle Real San Luis Obispo, Ca 93401 Goleta, CA 93117 Fax (805) 543-2685 Fax (805) 976-4386 is swept away by a flow of dry nitrogen around the outside of (805) 543-2553 (805) 964-7838 Central Coast Analytical Services, Inc. Analytical Method for the Accurate Determination of Organic Compounds in Air Abstract Central Coast Analytical Services (CCAS) has developed an analytical method for the accurate determination of atmospheric concentrations of non -methane organic compounds in ambient air and landfill gases. The method employs cryogenic trapping to isolate trace organic compounds from the sample followed by fused silica capillary column gas chromatography/ mass spectrometry. Certified Reference Standards traceable to NBS Standard Reference Materials (SRMs) and internal standards are used to insure the accuracy of the measurements. Experimental Method Air samples from Tedlar bags or electropolished stainless steel canisters are analyzed for toxic organic compounds with detection limits in the sub part -per -billion range. The analytical technique employs cryogenic trapping to isolate trace organic components in ambient air from major air components such as oxygen and nitrogen. An evacuated reservoir of known volume is used to pull air from a sample bag (Tedlar) or electropolished stainless steel canister through a sample loop which is immersed in liquid argon (-186 C). The sample loop is packed with 60/80 mesh inert glass beads to provide a large surface area for condensation of the organics. A vacuum gauge attached to the reservoir is used to measure the pressure drop caused by transfer of the sample from the sample container to the reservoir. Since the volume of the reservoir is accurately known, the amount of air drawn through the sample loop can be calculated. Approximately 500 mL of sample is drawn through the sample loop at a rate of 25-50 mL/min. Since atmospheric water vapor will also condense at the liquid argon temperatures, and because this water can cause problems with the subsequent GC/MS analysis, a Nafion dryer is placed between the sample and the cryogenic sample loop. Nafion is an inert material selectively An aliquot (0.25 mL) of an internal standard mixture containing bromochloromethane and bromochloropropone in nitrogen is added to the sample by first loading it into a 0.25 mL loop and flushing it into the sample loop with 100 mL of zero air. The internal standard is added to the sample loop concurrently with the sample. u permeable to water. Moisture in the sample passes through the Nafion tubing and is swept away by a flow of dry nitrogen around the outside of the tube. Organic constituents in the sample have little or no tendency to permeate their original the Nafion tubing, and they pass through to the sample loop at concentration. An aliquot (0.25 mL) of an internal standard mixture containing bromochloromethane and bromochloropropone in nitrogen is added to the sample by first loading it into a 0.25 mL loop and flushing it into the sample loop with 100 mL of zero air. The internal standard is added to the sample loop concurrently with the sample. u