EXPLORATION OF A MULTICAPILLARY COLUMN FOR USE IN ELEVATED SPEED GAS-CHROMATOGRAPHY

Elevated speed gas chromatography with a multicapillary column (MCC) w as explored using mixtures of volatile alkanes and aromatic hydrocarbo ns with a 160 mm long MCC at 27 degrees C. The van Deemter curves show ed broad minima with volumetric flows from 10-60 mL/min (average linea r velocities of 12-70 cm/s) and HETP values of 0.5-3 mm; corresponding retention limes were 10-200 s. in comparison, a 2.89 m fused silica c apillary column exhibited narrower minima with volumetric flows of 5-2 0 mL/min (average linear velocities of 105-418 cm/s) and HETP values o f 2-70 mm; retention times were 10-60 s at 41 degrees C. The MCC exhib ited symmetry factors of ca. 1.3 at 10 ng and this rose to ca. 2.0 at 100 mu g; 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 o f the MCC suggests that major advantages exist with respect to low sen sitivity in separation efficiency towards carrier gas flow rates and s ample loading to at least 10 mu g. The mechanical advantages of a MCC were also exploited revealing the simplicity of connecting it to other parts of a GC system.