Department of Analytical Chemistry and Food Technology, University of Castilla-La Mancha, Avenue Camilo José Cela s/n 13004, Ciudad Real, Spain.
Regional Institute for Applied Chemistry Research, IRICA, Avenue Camilo José Cela s/n 13004, Ciudad Real, Spain.
Mikrochim Acta. 2021 Nov 30;188(12):440. doi: 10.1007/s00604-021-05098-0.
Highly reliable separation and determination of various biologically active compounds were achieved using capillary electrophoresis (CE) based on β-cyclodextrin-functionalized graphene quantum dots (βcd-GQDs) as the background electrolyte additive. βcd-GQDs improve the separation efficiency between peaks of all analytes. No addition of surfactants or organic solvents was needed in the running buffer containing βcd-GQDs. Up to eight consecutive runs were acquired with high precision for the separation of resveratrol, pyridoxine, riboflavin, catechin, ascorbic acid, quercetin, curcumin, and even of several of their structural analogs. Baseline separation was achieved within just 13 min as a result of the effective mobility of the analytes along the capillary owing to the differential interaction with the additive. The proposed analytical method displayed a good resolution of peaks for all species selecting two absorption wavelengths in the diode array detector. Detection limits lower than 0.28 µg mL were found for all compounds and precision values were in the range of 2.1-4.0% in terms of the peak area of the analytes. The usefulness of the GQD-assisted selectivity-enhanced CE method was verified by the analysis of food and dietary supplements. The applicability to such complex matrices and the easy and low-cost GQD preparation open the door for routine analyses of food and natural products. The concept of using such a dual approach (macromolecules and nanotechnology) has been explored to tackle the separation of various bioactive compounds in nutritional supplements and food. Schematic illustration of the electrophoretic separation of the bioactive molecules in the capillary which is filled with the running solution without (top) and with βcd-GQDs (bottom). The fused silica capillary with negatively ionizable silanol groups at the wall. The voltage is applied at positive polarity at the outlet. R, riboflavin; r, resveratrol; P, pyridoxine; C, catechin; c, curcumin; A, ascorbic acid; Q, quercetin.
采用基于β-环糊精功能化石墨烯量子点（βcd-GQDs）作为背景电解质添加剂的毛细管电泳（CE），实现了对各种生物活性化合物的高可靠性分离和测定。βcd-GQDs 提高了所有分析物峰之间的分离效率。在含有βcd-GQDs 的运行缓冲液中，无需添加表面活性剂或有机溶剂。对于白藜芦醇、吡哆醇、核黄素、儿茶素、抗坏血酸、槲皮素、姜黄素甚至它们的几种结构类似物的分离，可获得高达 8 次连续的高精度分离。由于分析物在毛细管中的有效迁移率，由于与添加剂的差异相互作用，在 13 分钟内实现了基线分离。通过二极管阵列检测器选择两个吸收波长，为所有物种实现了良好的峰分辨率。对于所有化合物，检测限均低于 0.28µg·mL，分析物峰面积的精密度值在 2.1-4.0%范围内。通过对食品和膳食补充剂的分析，验证了 GQD 辅助选择性增强 CE 方法的有用性。这种方法适用于复杂基质，且 GQD 制备简单且成本低，为食品和天然产物的常规分析开辟了道路。该方法探索了使用这种双重方法（大分子和纳米技术）的概念，以解决营养补充剂和食品中各种生物活性化合物的分离问题。用没有（上图）和有βcd-GQDs（下图）的运行溶液填充毛细管的电泳分离生物活性分子的示意图。带有带负电荷的硅醇基团的熔融石英毛细管。在出口处施加正极性电压。R，核黄素；r，白藜芦醇；P，吡哆醇；C，儿茶素；c，姜黄素；A，抗坏血酸；Q，槲皮素。
