The present studies focus on the intrinsic role of poly(3,4-ethylenedioxythiophene) (PEDOT) in electrooxidation of caffeic acid (CA) in view of the application of this electrode material in electroanalytical sensing. Electrosynthesized PEDOT layers with different thickness and different doping counterions are investigated. Based on the scan rate dependence of the voltammetric peak currents it is found that depending on the thickness of the polymer layer different factors, i.e. adsorption for thin layers and diffusion for thick layers, are rate determining. In terms of electroanalytical characteristics it is established that adsorption control provides the opportunity to obtain higher electroanalytical sensitivity in a narrow concentration range of linear response. Diffusion control results in markedly lower sensitivity values but extended range of linearity in the concentration dependence. In the case of adsorption control a hyperbolic equation of the Langmuir/Michaelis–Menten type is suggested to model the experimentally obtained non-linear concentration dependence of the peak currents. The use of a non-linear calibration curve provides an extended concentration range for electroanalytical work under the established adsorption controlled conditions. Doping counterions (polysterene sulfonate and dodecyl sulfate) are found to have no effect on the electroanalytical performance of PEDOT for CA oxidation.

鉴于该电极材料在电分析感测中的应用，本研究集中于聚（3,4-乙撑二氧噻吩）（PEDOT）在咖啡酸（CA）电氧化中的内在作用。研究了具有不同厚度和不同掺杂抗衡离子的电合成PEDOT层。基于伏安峰电流的扫描速率依赖性，发现取决于聚合物层的厚度，决定速率的因素是不同的，即对薄层的吸附和对厚层的扩散。就电分析特性而言，可以确定的是，吸附控制为在狭窄的线性响应浓度范围内获得更高的电分析灵敏度提供了机会。扩散控制导致灵敏度值明显降低，但浓度依赖性的线性范围扩大。在吸附控制的情况下，建议使用Langmuir / Michaelis-Menten类型的双曲方程来对通过实验获得的峰值电流的非线性浓度依赖性进行建模。非线性校准曲线的使用为在既定的吸附控制条件下进行电分析工作提供了扩展的浓度范围。发现掺杂抗衡离子（聚苯乙烯磺酸盐和十二烷基硫酸盐）对PEDOT进行CA氧化的电分析性能没有影响。在吸附控制的情况下，建议使用Langmuir / Michaelis-Menten类型的双曲方程来对通过实验获得的峰值电流的非线性浓度依赖性进行建模。非线性校准曲线的使用为在既定的吸附控制条件下进行电分析工作提供了扩展的浓度范围。发现掺杂抗衡离子（聚苯乙烯磺酸盐和十二烷基硫酸盐）对PEDOT进行CA氧化的电分析性能没有影响。在吸附控制的情况下，建议使用Langmuir / Michaelis-Menten类型的双曲方程来对通过实验获得的峰值电流的非线性浓度依赖性进行建模。非线性校准曲线的使用为在既定的吸附控制条件下进行电分析工作提供了扩展的浓度范围。发现掺杂抗衡离子（聚苯乙烯磺酸盐和十二烷基硫酸盐）对PEDOT进行CA氧化的电分析性能没有影响。