Polyimide Filaments as a Novel Stationary Phase in Packed-Capillary Gas Chromatography

A fine fibrous polyimide (PI) material was introduced as a stationary phase in packed capillary gas chromatography (GC). Packed longitudinally into a capillary, the bundle of the PI filaments exhibited retentivity for a set of test analytes, showing that the PI-packed column was able to work as a stationary phase in GC. On the basis of a systematic consideration of the retention factors for homologous alkanes, it was confirmed that a good linear relationship between the carbon number and the logarithmic retention factor for alkanes at a constant column temperature. Linear van't Hoff plots were also obtained for alkanes, where logarithmic retention factors were plotted against the reciprocal absolute column temperatures. On the basis of the tendency in the retention factors of homologous alkane test analytes, the PI stationary phase has a trend for the retention behavior similar to that of conventional GC stationary phases widely employed, although a certain contribution of polar functional groups in the PI stationary phase to the retention of alcohols was observed. Taking advantage of the good heat-resistance of the PI material, an applicability to temperature-programmed GC separations was also suggested for the fibrous PI stationary phase.