Large volume injection in fast gas chromatography with on-column injector

In this work a fast gas chromatography set-up with on-column injection was optimized and evaluated with a model mixture of C 8 -C 28 n-alkanes. Usual injection volumes when using narrow-bore (e.g., 0.1 mm i.d.) analytical columns are ca. 0.1 μL. The presented configuration allows introduction of 10-30-fold larger sample volumes without any distortion of peak shapes. In the set-up a normal-bore retention gap (1 m × 0.32 mm i.d.) was coupled to a narrow-bore (4.8 m x 0.1 mm i.d. x 0.4 μm film thickness) analytical column using a low dead volume column connector. The effects of the experimental conditions such as inlet pressure, sample volume, initial injection temperature, and oven temperature on a peak focusing are discussed. H-u curves for helium and hydrogen are used to compare their suitability for high speed gas chromatography and to show the dependence of separation efficiency on the carrier gas velocity at high inlet pressures. In the fast gas chromatography system a baseline separation of C 10 -C 28 n-alkanes was achieved in less than 3 minutes.