National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan.
Dr. M. A. Kazi Institute of Chemistry, University of Sindh, Jamshoro, Pakistan.
Electrophoresis. 2018 Jul;39(13):1606-1612. doi: 10.1002/elps.201700421. Epub 2018 Mar 30.
Recently, an increasing interest has been observed in ionic liquids (ILs) due to their potentialities in various chemical processes. ILs have some unique properties making them excellent additives in CE. In this work a simple, rapid, and reliable CZE method has been developed and validated using 1-butyl-3-methyl imidazolium hexafluorophosphate (BMIM-PF ) ionic liquid as a buffer additive for the determination/separation of five flavonoids including hesperedin, epicatechin (EC), epigallocatechin gallate (EGCG), and morin using photodiode array (PDA) detector. The effect of several parameters such as concentration and pH of the running buffer, applied voltage, and concentration of ionic liquid were optimized. CZE at 25°C with 25 mM borate buffer of pH 9.0 at an applied voltage of 17 kV by adding 17.5 mM of IL was found to be suitable for the separation/determination of all five analytes within 08 min. Validation of the method was performed in terms of linearity, accuracy, precision, and limit of detection and quantification. The calibration curves were plotted in the concentration range of 1-200 μg/mL for all five analytes. The response was linear with R = 0.990 for EC, chrysin, and hesperidin, 0.992 for morin, and 0.988 for EGCG. LOD and LOQ were obtained within the range of 0.4-0.5 and 1.4-1.7 μg/mL, respectively. The proposed method showed good reproducibility with RSD of less than 3% for both migration time and peak height. The method was successfully applied for the determination of flavonoids from citrus fruits and tea samples.
最近，由于离子液体（ILs）在各种化学过程中的潜力，人们对其产生了越来越大的兴趣。ILs 具有一些独特的性质，使其成为 CE 的优秀添加剂。在这项工作中，开发并验证了一种简单、快速、可靠的 CZE 方法，使用 1-丁基-3-甲基咪唑六氟磷酸盐（BMIM-PF）离子液体作为缓冲添加剂，用于测定/分离五种黄酮类化合物，包括橙皮苷、表儿茶素（EC）、表没食子儿茶素没食子酸酯（EGCG）和桑色素，使用光电二极管阵列（PDA）检测器。优化了几种参数的影响，如运行缓冲液的浓度和 pH 值、施加电压和离子液体的浓度。在 25°C 下，使用 25 mM 硼酸缓冲液（pH 9.0），施加 17 kV 的电压，并添加 17.5 mM 的 IL，发现适合于在 08 分钟内分离/测定所有五种分析物。该方法的验证是在线性、准确性、精密度和检测限和定量限方面进行的。所有五种分析物的校准曲线均在 1-200μg/mL 的浓度范围内绘制。EC、白杨素和橙皮苷的响应呈线性，R 为 0.990，桑色素为 0.992，EGCG 为 0.988。LOD 和 LOQ 的范围分别为 0.4-0.5 和 1.4-1.7μg/mL。该方法显示出良好的重现性，迁移时间和峰高的 RSD 均小于 3%。该方法成功应用于柑橘类水果和茶叶样品中黄酮类化合物的测定。
