Barsan Madalina M, Pinto Edilson M, Florescu Monica, Brett Christopher M A
Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
Anal Chim Acta. 2009 Mar 2;635(1):71-8. doi: 10.1016/j.aca.2009.01.012. Epub 2009 Jan 14.
A new conducting composite flexible material prepared from cellulose acetate (CA) polymer and graphite has been developed and used for the fabrication of electrodes, which were then characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Scanning electron microscopy (SEM) was used to provide information concerning the morphology of the composite electrode surface. The potential window, background currents and capacitance were evaluated by cyclic voltammetry in the pH range from 4.6 to 8.2. The voltammetry of model electroactive species demonstrates a close to reversible electrochemical behaviour, under linear diffusion control. The electroactive area of the composite electrodes increases after appropriate electrode polishing and electrochemical pre-treatment. The electrodes were used as substrate for the electropolymerisation of the phenazine dye neutral red, for future use as redox mediator in electrochemical biosensors. The composite electrodes were also successfully used for the amperometric detection of ascorbate at 0.0 V vs. SCE, and applied to the measurement of ascorbate in Vitamin C tablets; the sensor exhibits high sensitivity and a low detection limit of 7.7 microM. Perspectives for use as a versatile, mechanically flexible and robust composite electrode of easily adaptable dimensions are indicated.
一种由醋酸纤维素（CA）聚合物和石墨制备的新型导电复合柔性材料已被开发出来，并用于制造电极，然后通过循环伏安法和电化学阻抗谱对其进行表征。扫描电子显微镜（SEM）用于提供有关复合电极表面形态的信息。通过在pH值为4.6至8.2的范围内进行循环伏安法来评估电位窗口、背景电流和电容。在线性扩散控制下，模型电活性物质的伏安法显示出接近可逆的电化学行为。经过适当的电极抛光和电化学预处理后，复合电极的电活性面积增加。这些电极被用作吩嗪染料中性红电聚合的底物，以便将来在电化学生物传感器中用作氧化还原介质。复合电极还成功地用于在相对于饱和甘汞电极（SCE）为0.0 V时对抗坏血酸进行安培检测，并应用于维生素C片中抗坏血酸的测量；该传感器具有高灵敏度和7.7微摩尔的低检测限。文中指出了将其用作尺寸易于调整的通用、机械柔性且坚固的复合电极的前景。
