Valveless Sampling of Ambient Air for Analysis by Capillary Gas Chromatography

A method for the high resolution, high sensitivity analysis of polluted air for individual organic compounds is described. Samples collected from 50 mL of ambient air at 87 K (liquid argon) are Injected without use of a valve into a silica capillary column which Is then temperature programmed from — 30°C to 180°C. Hydrocarbons (4 to 10 carbons) as well as carbonyl compounds, chlorinated compounds and terpenes can be identified and quantified. The detection limit, not strongly dependent on carbon number, is estimated to be 0.3 ppbc in a 50 mL sample. Use of small samples eliminates the need to remove water vapor, a procedure which might jeopardize sample integrity.