Polymer-Coated Fibrous Stationary Phases in Packed-Capillary Gas Chromatography

Abstract

Gas chromatography (GC) is regarded as an essential separation method for the analysis of volatile compounds, and a wide variety of polymeric liquid-phases have been developed as the stationary phase. 1,2 Various deactivation and polymer-coating processes have been also proposed for the preparation of GC columns with good separation performance and stability. [3][4][5][6] In contrast to the successful applications and subsequent commercialization of these polymer-coated columns, such as wall-coated, support-coated and pellicular-coated, the reports for the fibrous polymer-packed stationary phases, however, have been limited, except for characterizing the surface of the fibers in inverse GC (IGC). 7,8 In general, the surface characteristics of the fiber have been analyzed with IGC technique by injecting the standard samples into a fiber-packed column and measuring the elution behavior. This characterization method is based on the observation of the specific interactions between the surface of the fibers and the standard solutes injected as the probes. Consequently, it is quite natural that a synthetic fiber can be employed as a separation medium in GC, if the fiber possesses both the thermal stability for the operation at an elevated temperature and the resistance to the gaseous chemical species through the column during the separation.In terms of the use of fibrous stationary phase in liquid phase separation methods, several applications have been reported. Kiso et al. introduced fibrous cellulose acetate (CA) stationary phase for the separation of alcohols 9 and polycyclic aromatic hydrocarbons (PAHs) 10 in microcolumn LC, and Jinno et al.reported the application of CA phase in capillary electrochromatography (CEC). 11,12 Recently, the possibility of the several synthetic fibers as the stationary phase in CEC 13 was also demonstrated. Although the separation efficiency of those columns was still not comparable with those of conventional particle-packed columns such as octadecylsilica (ODS) phase, and moreover, there were several limitations on the mobile phase composition and the packing density, still it has been clearly shown that the packed filaments could play the role as a stationary phase. Saito et al. have also reported the successful applications of fibrous polymeric material as an extraction medium for novel miniaturized sample preparations specially designed for the on-line coupling to microcolumn liquid phase separation methods. 14-22 On the basis of the above successful applications of fibrous materials as the stationary phase and the extraction medium, fiber-packed fused-silica capillaries have been introduced in our previous study for the separation of volatile compounds in GC. 23In this work, polymer coating onto the packed-filaments in a capillary was investigated using several conventional polymeric materials as the liquid-phase for capillary GC columns. As the fibrous material, Zylon ® [poly(p-phenylene-2,6-benzobisoxazole)] fiber ( Fig. 1) was employed, taking into account the heat resistance...

High-Temperature Separations on a Polymer-Coated Fibrous Stationary Phase in Microcolumn Liquid Chromatography

“…The results clearly demonstrated the contribution of the polymeric coating to the surface of the fine fibrous support material on the retentivity to these analytes. [23][24][25] In those studies, even if the retentivities to homologous analytes were different, a general trend in the selectivity between these analytes could be similar, suggesting the existence of an optimum combination of the type of polymeric coating and the fibrous material. 25,39 Based on a successful polymeric coating on the surface of Zylon fiber, confirmed as the increased retentivity to two typical non-polar analytes in Table 1, the HR-17 coating was chosen as the main coating material in following experiments.…”

“…[23][24][25][26] First, a fused-silica capillary of 0.32 mm i.d., 1.0 m length packed with 332 of Zylon filaments was connected to a pressure-proof vessel containing 10 mL of acetone, and washed with a solvent pumped by N2 gas at a pressure of 500 kPa. After the same volumes of the following solvents, water, acetone and chloroform, were pumped in a similar manner, the capillary was allowed to dry by using N2 gas flow at room temperature for about 2 h. Second, the capillary was subjected to heating in a GC oven with the flow of N2 gas.…”

“…[15][16][17][18][19][20][21][22] These fibrous materials were also employed as a stationary phase in GC, because of their excellent thermal stability over the temperature range typically used in most of GC separations. [23][24][25][26][27] Coated with typical polysiloxane-based materials onto the surface of the fibrous materials, the retentivity was significantly improved, and also the selectivity could be designed on the basis of the type of polymeric coatings. [24][25][26][27] In terms of the fibrous stationary phases in micro-LC, Kiso et al have reported examples of the separation of alcohols and polycyclic aromatic hydrocarbons (PAHs) on capillary columns packed with fibrous cellulose acetate.…”

“…[23][24][25][26][27] Coated with typical polysiloxane-based materials onto the surface of the fibrous materials, the retentivity was significantly improved, and also the selectivity could be designed on the basis of the type of polymeric coatings. [24][25][26][27] In terms of the fibrous stationary phases in micro-LC, Kiso et al have reported examples of the separation of alcohols and polycyclic aromatic hydrocarbons (PAHs) on capillary columns packed with fibrous cellulose acetate. 28,29 Marcus et al applied so-called capillary-channeled polymer (C-CP) fibers as stationary phases in LC.…”

Rapid Temperature-Programmed Separation and Retention Prediction on a Novel Packed-Capillary Column in Gas Chromatography

“…Introducing polymer-coated fine fibrous materials as a stationary phase in GC, a significant miniaturization of the column was reported, [4][5][6][7] similar to the development of microscale sample preparation devices, where the filaments were packed into a short polymeric tubing, such as polyetheretherketone or polytetrafluoroethylene to prepare capillary-based extraction cartridges. [8][9][10] Packed with a bundle of filaments having a polymeric coating material thereon, a parallel alignment of these filaments was formed in a short capillary, and the resulting polymer-coated fiber-packed columns showed a satisfactory separation performance with a fast temperature-programming rate in GC.…”