Background: Nowadays, polymeric composites modified with carbonaceous nanomaterials have been popular due to their greater application potentials in many application fields. However, the structural consistency of the composite prepared by electropolymerization suffers from agglomeration of Carbon Nanotubes (CNTs) probably due to their poor dispersion in the coating solution. Present study describes a new synthesis route for the preparation of polypyrrole/CNT composite film on a Glassy Carbon Electrode (GCE) via combining the ultrasonication and electrochemical pulsed deposition for the first time. The performance of the composite film was tested by monitoring the electrochemical oxidation of droxidopa which is used as a new psychoactive drug and synthetic amino acid precursor which acts as a prodrug to the neurotransmitters.

Methods: The polypyrrole/CNT composite film was deposited onto a glassy carbon electrode via combining the ultrasonication and electrochemical pulsed deposition. The composite film was characterized by Scanning Electron Microscopy (SEM), Fourier Transfer Infrared Spectroscopy (FTIR), Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV). Then after, the electrochemical behavior of droxidopa was investigated on the GCE/PPy-CNT electrode.

Results: SEM images of the surface morphology have revealed a more ordered film formation and enhanced conductivity of the surface has been confirmed by EIS measurements. The synergetic effect of this composite film was tested by monitoring the electrochemical oxidation of a new psychoactive drug; droxidopa at 0.45 V. The influence of solution parameters such as medium pH, pyrrole concentration and amount of CNT along with the instrumental parameters including applied pulse number on the peak formation was investigated by aid of cyclic voltammetry. Under the optimal conditions, by monitoring the oxidation peak in dp mode, two linear ranges have been observed in 4 - 20 μM which is well suited for droxidopa analysis in pharmaceutical preparations. The limit of detection (S/N=3) was calculated as 1.3 μM.

Conclusion: Present study offers a fast, easy and sensitive method for the determination of droxidopa by providing a novel route for the preparation of PPy-CNT composite films for any further studies.

背景：如今，用碳纳米材料改性的聚合物复合材料由于在许多应用领域具有更大的应用潜力而受到欢迎。然而，通过电聚合制备的复合材料的结构一致性由于碳纳米管（CNT）在涂层溶液中的分散性差而遭受团聚。目前的研究描述了一种新的合成途径，该方法首次将超声和电化学脉冲沉积相结合，在玻碳电极（GCE）上制备聚吡咯/ CNT复合膜。通过监测作为一种新型精神活性药物的droxidopa和作为神经递质前药的合成氨基酸前体的电化学氧化，来测试复合膜的性能。

方法：通过超声和​​电化学脉冲沉积相结合的方法将聚吡咯/ CNT复合膜沉积在玻璃碳电极上。通过扫描电子显微镜（SEM），傅立叶转移红外光谱（FTIR），电化学阻抗谱（EIS）和循环伏安法（CV）表征复合膜。然后，在GCE / PPy-CNT电极上研究了草甘膦的电化学行为。

结果：表面形态的SEM图像显示出更有序的膜形成，并且通过EIS测量已确认表面的导电性增强。通过监测一种新型精神活性药物的电化学氧化来测试这种复合膜的协同作用。在0.45 V下使用乙草胺。通过循环伏安法研究了溶液参数（如中等pH，吡咯浓度和CNT量）以及仪器参数（包括施加的脉冲数）对峰形成的影响。在最佳条件下，通过监测dp模式下的氧化峰，已观察到4-20μM的两个线性范围，非常适合药物制剂中的去氧多巴分析。检测限（S / N = 3）计算为1.3μM。

结论：本研究通过提供一种制备PPy-CNT复合膜的新方法，为进一步研究提供了一种快速，简便，灵敏的测定多菌灵的方法。