A previously developed capillary zone electrophoresis (CZE) method with indirect UV detection for the simultaneous determination of inorganic and organic anions, amino acids and carbohydrates using 20 mM 2,6-pyridinedicarboxylic acid (PDC) as the background electrolyte was extended to allow determination of 206 anions including those above--mentioned and physiological amino acids, nucleotides, aromatic acids, haloacetic acids, alcohols, phosphorylated saccharides, oxyhalides, metal oxoacids, metal-ethylenediaminetetraacetic acid (EDTA) complexes, forensic anions, Good's buffers and herbicides. Every compound could be analyzed and their electrophoretic mobility determined simply by selecting detection wavelength. This method is simple and universal for anion analysis, and could be readily applied to the simultaneous determination of anionic compounds. In this work, it was used to identify and quantify important anions in sea urchin and sake.
A fibrous rigid-rod polymer was successfully introduced as the station-Ž . ary phase in capillary gas chromatography GC and the basic separation perfor-ᮋ Ž . mance was investigated. Zylon , poly p-phenylene-2,6-benzobisoxazole , fibers were adopted as the stationary phase taking into account the chemical structure, heat resistance, solvent resistance, and the physical strength for the convenience in column packing process. About 330 and 600 filaments of the polymer were packed longitudinally into fused-silica capillaries of 0.32 and 0.53 mm inner diameter, respectively, and the separation of several test mixtures, such as n-alkylbenzenes and n-alkanes was carried out with these fiber-packed capillary columns in GC. The results clearly indicated that the fiber-packed capillary columns have a great potential as the separation media for volatile compounds. The results also showed the possibility of the synthesis of novel tailored polymer fiber to separate particular class of compounds based on the specific selectivity by the chemical structure of the fiber. Coated-fiber packings were also evaluated to confirm the contribution of the fibers and the coatings to the separation characteristics.
A novel "fiber-in-tube" configuration has been applied to the extraction tube of solid phase microextraction (SPME), and the direct coupling of the extraction process to liquid chromatography (LC) has been accomplished for the analysis of n-butylphthalate in wastewater. By using this fiber-in-tube SPME/LC system the preconcentration factor for the phthalate was about 160 with 20 min extraction and no interference peak was observed in the chromatogram. The results also showed the potential applications of this fiber-in-tube SPME/LC for the analysis of sub-ppb level (i.e., lower than 1 ng/mL) of various organic analytes in aqueous sample matrix without a large solvent consumption during the preconcentration process.
Synthetic polymer filaments have been introduced as the support material in packed capillary gas chromatography (GC). The filaments of the heat-resistant polymers, Zylon, Kevlar, Nomex, and Technora, were longitudinally packed into a short fused-silica capillary, followed by the conventional coating process for open-tubular GC columns. The separation of several test mixtures such as n-alkylbenzenes and n-alkanes was carried out with these polymer-coated fiber-packed capillary columns. With the coating by various polymeric materials on the surface of these filaments, the retentivity was significantly improved over the parent fiber-packed column (without polymer coating) as well as a conventional open-tubular capillary of the same length. The results demonstrated a good combination of Zylon as the support and poly(dimethylsiloxane)-based materials as the coating liquid-phase for the successful GC separation of n-alkanes and polycyclic aromatic hydrocarbons (PAHs), while successful applications for other separations such as poly(ethylene glycol) coating for the separation of alcohols were also obtained. From the results it has been suggested that the selectivity of the fiber-packed column could be tuned by selecting different coating materials, indicating the promising possibility for a novel usage of fine fibrous polymers as the support material that can be combined with newly synthesized coating materials specially designed for particular separations. Taking advantage of good thermal stability of the fibers, the column temperature could be elevated to higher than 350 degrees C with the combination of a short metallic capillary.
Miniaturized fiber-in-tube solid-phase extraction (fiber-in-tube SPE) has been developed as a solventless sample preconcentration technique for microcolumn liquid-phase separation methods. Short capillaries packed with polymer filaments were employed as the extraction tube and the preconcentration power for phthalates in aqueous solutions was studied. On the basis of the successful on-line coupling of this preconcentration method with liquid chromatography (LC), a more miniaturized extraction cartridge, which is installed in the rotor of the micro-injector, has been developed. With a modified commercially available valve, on-line coupling of this sample preconcentration method to capillary electrochromatography (CEC) was also investigated.
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