摘要： 自制了紫外-可见分光光度计的微柱电泳高效分离附件, 介绍了X射线衍射法在电泳微柱制备中的应用以及微柱电泳与紫外-可见分光光度法的在线联用。使用水热法合成均匀石英微米晶粒，采用X射线衍射法表征和控制产物的晶相，并用扫描电子显微镜观察产物形貌。将合成的石英微米晶粒均匀填充在2 mm i.d.石英管中，制成电泳微柱。通过微柱电泳与紫外-可见分光光度法在线联用，对非衍生的色氨酸、苯丙氨酸和酪氨酸进行了分离检测。检出限分别为0.037, 0.20和0.20 μmol·L-1，色氨酸的分离效率为每米4.5×104，电泳微柱的样品容量达到35 μL。实验结果表明，填充石英微米晶粒的微柱电泳可抑制大柱径电泳热效应，增大样品容量，提高检测灵敏度。微柱电泳与常规紫外-可见分光光度法联用可简便地对混合物进行在线分离和测定，进一步拓宽了紫外-可见分光光度计在光谱重叠组分痕量分析中的应用。
关键词：微柱电泳;高效分离附件;紫外-可见分光光度计;水热合成;石英微米晶粒;X射线衍射法;氨基酸
Abstract：In the present paper, a laboratory-made high-performance electrophoresis microcolumn unit was prepared for UV-Vis spectrophotometer. X-ray diffraction was used in the preparation of electrophoretic microcolumns. And an analytical technique of microcolumn electrophoresis coupled with UV-Vis spectrophotometry was introduced. Uniform quartz microncrystals were prepared by hydrothermal synthesis. Their crystalline phase and morphology were identified by X-ray diffraction and scanning electron microscope, respectively. The quartz microncrystals were packed into a 2-mm i.d. fused-silica tube to prepare the electrophoretic microcolumn. With 1.5 mmol·L-1 disodium phosphate buffer solution (pH 11.5) containing 25% (φ) methanol and 10% (φ) acetonitrile, tryptophan, phenylalanine and tyrosine were on-line separated on line and detected by microcolumn electrophoresis coupled with UV-Vis spectrophotometry without derivatization. The limits of detection were 0.037, 0.20 and 0.20 μmol·L-1, respectively. The separation efficiency of tryptophan was 4.5×104 plates/m. The sample capacity of the electrophoretic microcolumn achieved 35 μL. It was found that the electrophoretic microcolumn packed with quartz microncrystals was able to limit Joule heat, increase sample capacity and enhance detection sensitivity. The laboratory-made electrophoretic microcolumn could be a high-performance separation unit for conventional UV-Vis spectrophotometer. The on-line coupling of microcolumn electrophoresis and UV-Vis spectrophotometry could separate and determine samples with complicated matrices, reduce zone broadening and enhance separation efficiency, so expand the analytical function of spectrophotometer in the trace analysis of mixed components with overlapped spectra.
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