Abstract
Spherical polyimide (PI) particles have been introduced as a stationary phase in liquid chromatography (LC). The PI was prepared with the starting materials of pyromellitic dianhydride (PMDA) and 4,4'-diaminodiphenyl ether (4,4'-oxydianiline, ODA), resulting the spherical PI (PMDA-ODA type) particles with an average diameter of about 5 μm. The synthesized PI particles were packed into a conventional blank LC column having a typical size of 4.6 mm i.d, 150 mm length, and the retention behavior for a group of polycyclic aromatic compounds (PACs) was evaluated in LC. The retention behavior was compared with that obtained on a commercially-available octadecylsilica (ODS) phase. The results indicated a significantly larger retentivity of PACs on the PI stationary phase than that on typical ODS stationary phases, where the retention tendency on the PI phase for various PACs having different molecular size and shape was similar to the trend on the ODS phase. The large retention on the PI phase can be interpreted on the basis of the surface structure of the PI particles, because a number of aromatic functionalities are in the chemical structure of the polymer chain backbone.
