Exploration of a Multicapillary Column for Use in Elevated Speed Gas Chromatography

Abstract

Elevated speed gas chromatography with a multicapillary column (MCC) was explored using mixtures of volatile alkanes and aromatic hydrocarbons with a 160 mm long MCC at 27°C. The van Deemter curves showed broad minima with volumetric flows from 10–60 mL/min (average linear velocities of 12–70 cm/s) and HETP values of 0.5–3 mm; corresponding retention times were 10–200 s. In comparison, a 2.89 m fused silica capillary column exhibited narrower minima with volumetric flows of 5–20 mL/min (average linear velocities of 105–418 cm/s) and HETP values of 2–70 mm; retention times were 10–60 s at 41°C. The MCC exhibited symmetry factors of ca. 1.3 at 10 ng and this rose to ca. 2.0 at 100 μ; greater loadings may be possible but were precluded here by limitations in the injector rather than the column. Comparison in the separation of volatiles in gasoline showed comparable performance with the conventional fused-silica capillary column. A first examination of the MCC suggests that major advantages exist with respect to low sensitivity in separation efficiency towards carrier gas flow rates and sample loading to at least 10 μg. The mechanical advantages of a MCC were also exploited revealing the simplicity of connecting it to other parts of a GC system.