Department of Chemistry, Shanghai University, Shanghai 200444, PR China.
Department of Chemistry, Shanghai University, Shanghai 200444, PR China; Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444, PR China.
Talanta. 2018 Feb 1;178:449-457. doi: 10.1016/j.talanta.2017.08.076. Epub 2017 Sep 15.
In present study, a novel and facile electrochemical sensor based on glassy carbon electrode (GCE) modified with nitrogen-doped carbon nanotubes (N-CNT) decorated with poly (L-Cysteine) (PLCY) were fabricated and applied for the simultaneous voltammetric determination of theophylline (THEO) and caffeine (CAF). The morphology and structure of multilayer film modified on the surface of glassy carbon electrode were investigated successfully by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Raman Spectroscopy. And the properties of the modified electrode were investigated by Chronocoulometry (CC), Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) were utilized to investigate the electrochemical behavior of THEO and CAF on the composite film modified electrode. The results showed that the determination towards THEO and CAF can be operated at the same potential window with the oxidation current peak separated and non-interfering respectively. Compared to the bare GCE, the PLCY/N-CNT/GCE can signally meliorate the electrocatalytic activity towards the oxidation of THEO and CAF with a remarkably increase in the anodic peak currents of 495.94% and 465.48%. Under the optimal conditions, the fabrication multilayer film sensor had excellent performances in determination towards THEO and CAF with a wide linear dynamic range from 0.10 to 70.0μM and 0.40-140.0μM, low detection limit (S/N = 3) of 0.033μM and 0.20μM, respectively. The PLCY/N-CNT/GCE sensor also had advantages as easy-made, high-sensitivity, stability and reproducibility. Moreover, it was successfully used to analyze the THEO and CAF in green tee, oral theophylline sustained release tablets and energy drink sample with a satisfactory result.
在本研究中，制备了一种基于玻碳电极（GCE）修饰的氮掺杂碳纳米管（N-CNT）上修饰聚（L-半胱氨酸）（PLCY）的新型简便电化学传感器，并将其应用于同时测定茶碱（THEO）和咖啡因（CAF）的伏安法测定。成功地通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）和拉曼光谱研究了多层膜在玻碳电极表面的形貌和结构。通过计时库仑法（CC）、循环伏安法（CV）和差分脉冲伏安法（DPV）研究了修饰电极的性质，研究了复合膜修饰电极上 THEO 和 CAF 的电化学行为。结果表明，THEO 和 CAF 的测定可以在相同的电位窗口进行，氧化电流峰分离且互不干扰。与裸 GCE 相比，PLCY/N-CNT/GCE 可以显著改善 THEO 和 CAF 氧化的电催化活性，阳极峰电流分别显著增加了 495.94%和 465.48%。在最佳条件下，该多层膜传感器在测定 THEO 和 CAF 方面具有出色的性能，线性动态范围从 0.10 到 70.0μM 和 0.40-140.0μM，检测限（S/N = 3）分别为 0.033μM 和 0.20μM。PLCY/N-CNT/GCE 传感器还具有易于制造、高灵敏度、稳定性和重现性等优点。此外，它还成功地用于分析绿茶、口服茶碱缓释片和能量饮料样品中的 THEO 和 CAF，结果令人满意。
