Departamento de Química Analítica y Análisis Instrumental, Universidad Autónoma de Madrid. Madrid, Spain.
Electrophoresis. 2011 Apr;32(8):877-83. doi: 10.1002/elps.201000498. Epub 2011 Mar 10.
A method for the simultaneous detection of five polyphenols (caffeic, chlorogenic, ferulic and gallic acids and (+)-catechin) by CZE with electrochemical detection was developed. Separation of these polyphenols was performed in a 100 mM borate buffer (pH 9.2) within 15 min. Under optimized separation conditions, the performance of glassy carbon (GC) electrodes modified with multiwalled carbon nanotube layer obtained from different dispersions was examined. GC electrode modified with a dispersion of multi-walled carbon nanotubes (CNT) in polyethylenimine has proven to be the most suitable CNT-based electrode for its application as amperometric detector for the CZE separation of the studied compounds. The excellent electrochemical properties of this electrode allowed the detection of the selected polyphenols at +200 mV and improved the efficiency and the resolution of their CZE separation. Limits of detection below 3.1 μM were obtained with linear ranges covering the 10⁻⁵ to 10⁻⁴ M range. The proposed method has been successfully applied for the detection (ferulic, caffeic and gallic acids and (+)-catechin) and the quantification (gallic acid and (+)-catechin) of polyphenols in two different white wines without any preconcentration step. A remarkable signal stability was observed on the electrode performance despite the presence of potential fouling substances in wine.
建立了一种通过 CZE 与电化学检测同时检测五种多酚（咖啡酸、绿原酸、阿魏酸和没食子酸以及（+）-儿茶素）的方法。在 100 mM 硼酸盐缓冲液（pH 9.2）中，这些多酚在 15 分钟内得到分离。在优化的分离条件下，考察了不同分散体得到的多壁碳纳米管层修饰的玻碳电极的性能。在聚亚乙基亚胺中分散多壁碳纳米管（CNT）的 GC 电极被证明是最适合的 CNT 基电极，可作为安培检测器用于研究化合物的 CZE 分离。该电极具有出色的电化学性能，可在 +200 mV 下检测所选多酚，并提高其 CZE 分离的效率和分辨率。在 10⁻⁵ 至 10⁻⁴ M 范围内，检测限低于 3.1 μM，线性范围涵盖 10⁻⁵ 至 10⁻⁴ M。该方法已成功应用于两种不同白葡萄酒中多酚（阿魏酸、咖啡酸和没食子酸以及（+）-儿茶素）的检测（阿魏酸、咖啡酸和没食子酸以及（+）-儿茶素）和定量（没食子酸和（+）-儿茶素），无需任何预浓缩步骤。尽管葡萄酒中存在潜在的污垢物质，但在电极性能上观察到了显著的信号稳定性。
