Preconcentration of aqueous solution of aromatic compounds was successfully carried out with an extraction capillary packed with a bundle of polymer-coated filaments. The extracted analytes were sequentially eluted with a flow of pure water using programmed temperature elevation of the extraction capillary. The results clearly suggest that the polymer-coated fiber-packed capillary could be employed as a sample preparation medium for the analysis of aqueous matrices. The fraction of interest could be transferred to conventional microcolumn liquid chromatography (LC) allowing a heart cutting analysis of aqueous matrices. Stability of the fiber-packed capillary was confirmed with pure water as the mobile phase at elevated temperatures.

Spherical polyimide particles have been synthesized as an extraction medium of volatile organic compounds (VOCs) in air samples. The polyimide was prepared with the starting materials of pyromellitic dianhydride (PMDA) and 4,4'-diaminodiphenyl ether (4,4'-oxydianiline, ODA), resulting spherical particles having an average diameter of about 5 µm. Packed into a laboratory made mini-extraction tube, the synthesized PMDA-ODA particles were employed as the adsorbent for the subsequent analysis in capillary gas chromatography. The extraction capacities for acetone, hexane, toluene are 0.42, 0.24, 0.78 µmol/g, respectively. The recoveries for these typical organic compounds are more than about 95%. The results clearly showed a good adsorption ability of the PMDA-ODA particles to typical VOCs frequently found in indoor environments, suggesting a future possibility to develop a more miniaturized sample preparation device specially-designed for on-site sampling of indoor air samples.

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.

A needle-type sample preparation device packed cyclohexanone-coated fibers as an extraction medium has been developed for the gas chromatographic (GC) analysis of volatile amines in air samples. For a simultaneous derivatization/extraction of monoethanolamine (MEA), a fiber-packed needle was employed, where a bundle of heat resistant filaments, Zylon, poly(p-phenylene-2,6-benzobisoxazole) was packed longitudinally into the specially-designed needle. To the needle-type device, cyclohexanone was loaded in the preconditioning process. Gaseous MEA was sampled by a vacuum air sampler connected to the needle, and a simultaneous derivatization/extraction was carried out therein. Desorption of MEA derivative was successfully made at a heated GC injection port without using any desorption solvent. Introducing the simultaneous derivatization with cyclohexanone, the sensitivity was significantly improved, allowing a more sensitive detection of volatile amines. Taking advantage of the specially-designed needle, the needle was able to be stored for several days at room temperature after the sampling, where the derivatives of the volatile amines were stably trapped on the surface of the Zylon filaments in the needle.

A bundle of polymer-coated filaments was successfully introduced as an extraction medium for the preconcentration of an aqueous solution of aromatic compounds. The extraction was simply carried out with pumping the aqueous sample solution to the extraction capillary at ambient temperature. The extracted analytes were sequentially eluted with a flow of pure water using temperature-programmed heating of the extraction capillary in an oven. The results clearly suggest that the polymer-coated fiber-packed capillary could be employed in the sample preparation process for the analysis of various aqueous samples. Introducing the fractions eluted from the fiber-packed capillary to a conventional microcolumn liquid chromatography (micro-LC) system via a home-made valve-based modulator, an on-line coupled extraction/separation system was developed and a possibility to a pseudo-two-dimensional (pseudo-2D) LC separation of aromatic compounds in aqueous matrices has also been demonstrated.