Graduate Institute of Biomedical Materials and Tissue Engineering, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
J Sep Sci. 2013 Feb;36(4):803-8. doi: 10.1002/jssc.201200889. Epub 2013 Jan 22.
An online dynamic pH junction preconcentration method was developed for quantification of 5-aminolevulinic acid (ALA) by CE with the separation time less than 6 min. The optimal dynamic pH junction of ALA was carried out between pH 9.3 borate buffer (BGE, 40 mM) and pH 2.5 phosphate buffer (sample matrix, 40 mM) when 4.1 cm of sample plug was hydrodynamically injected into an uncoated fused-silica capillary (48.5 cm in length, id of 50 μm). If a 24 kV separation voltage was applied, the calibration curve of ALA peak area (200 nm) showed good linearity (R(2) = 0.9991) ranging from 0.01 to 6.5 mg/mL. The reproducibility of this system was excellent with RSDs (n = 10) of 2.5% for peak area response and 0.6% for migration time at ALA concentration of 0.5 mg/mL. The LOD was evaluated as 1.0 μg/mL (S/N > 3). Compared to conventional CE procedure, the sensitivity was successfully improved over 50-fold. The analytical results of pharmaceutical formulations show a good agreement with those by HPLC (r = 0.94).
建立了一种在线动态 pH 连接预浓缩方法，用于通过 CE 对 5-氨基乙酰丙酸 (ALA) 进行定量分析，分离时间小于 6 分钟。当将 4.1cm 的样品塞以水力方式注入未涂层的熔融石英毛细管（48.5cm 长，内径为 50μm）中时，ALA 的最佳动态 pH 连接在 pH9.3 硼酸盐缓冲液（BGE，40mM）和 pH2.5 磷酸盐缓冲液（样品基质，40mM）之间进行。如果施加 24kV 的分离电压，则 ALA 峰面积（200nm）的校准曲线表现出良好的线性（R²=0.9991），范围从 0.01 到 6.5mg/mL。该系统的重现性非常好，ALA 浓度为 0.5mg/mL 时，峰面积响应的 RSD（n=10）为 2.5%，迁移时间的 RSD 为 0.6%。LOD 评估为 1.0μg/mL（S/N>3）。与传统 CE 程序相比，灵敏度成功提高了 50 多倍。药物制剂的分析结果与 HPLC 的结果非常吻合（r=0.94）。
