Development of gas chromatography-flame ionization detection system with a single column and liquid nitrogen-free for measuring atmospheric C2–C12 hydrocarbons

• A liquid nitrogen-free GC-FID technique for measuring C2–C12 NMHCs was developed.
• OV-1 column can efficiently analyze C2–C12 NMHCs with GC in 31 min.
• The feature of this system is the custom sampling unit and separation unit.

A liquid nitrogen-free GC-FID system equipped with a single column has been developed for measuring atmospheric C2–C12 hydrocarbons. The system is consisted of a cooling unit, a sampling unit and a separation unit. The cooling unit is used to meet the temperature needs of the sampling unit and the separation unit. The sampling unit includes a dehydration tube and an enrichment tube. No breakthrough of the hydrocarbons was detected when the temperature of the enrichment tube was kept at −90 °C and sampling volume was 400 mL. The separation unit is a small round oven attached on the cooling column. A single capillary column (OV-1, 30 m × 0.32 mm I.D.) was used to separate the hydrocarbons. An optimal program temperature (−60 ∼ 170 °C) of the oven was achieved to efficiently separate C2–C12 hydrocarbons. There were good linear correlations (R2 = 0.993–0.999) between the signals of the hydrocarbons and the enrichment amount of hydrocarbons, and the relative standard deviation (RSD) was less than 5%, and the method detection limits (MDLs) for the hydrocarbons were in the range of 0.02–0.10 ppbv for sampling volume of 400 mL. Field measurements were also conducted and more than 50 hydrocarbons from C2 to C12 were detected in Beijing city.