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Abstract：
In this study, a facile approach for simultaneous determination of dopamine (DA) and tryptophan (TRP) using a 3D goethite-spongin-modified carbon paste electrode is reported. The prepared electrode exhibited excellent electrochemical catalytic activity towards DA and TRP oxidation. The electrochemical sensing of the modified electrode was investigated using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Through differential pulse voltammetry analysis, two well-separated oxidation peaks were observed at 28 and 77 mV, corresponding to the oxidation of DA and TRP at the working electrode, with a large peak separation of up to 490 mV. DA and TRP were determined both individually and simultaneously in their dualistic mixture. As a result, the anodic peak currents and the concentrations of DA and TRP were found to exhibit linearity within the ranges of 4-246 μM for DA and 2 to 150 μM for TRP. The detection limits (S/N = 3) as low as 1.9 μM and 0.37 μM were achieved for DA and TRP, respectively. The proposed sensor was successfully applied to the simultaneous determination of DA and TRP in human urine samples with satisfactory recoveries (101% to 116%).
摘要：
在这项研究中,报告了使用3D针铁矿-海绵蛋白修饰的碳糊电极同时测定多巴胺（DA）和色氨酸（TRP）的简便方法。制备的电极对DA和TRP氧化表现出优异的电化学催化活性。使用循环伏安法研究了修饰电极的电化学传感，差分脉冲伏安法,和电化学阻抗谱。通过差分脉冲伏安分析,在28和77mV处观察到两个分离良好的氧化峰，对应于DA和TRP在工作电极上的氧化，具有高达490mV的大峰分离。DA和TRP在其二元混合物中分别和同时测定。因此,发现阳极峰值电流以及DA和TRP的浓度在DA的4-246μM和TRP的2至150μM范围内呈线性。DA和TRP的检出限（S/N=3）低至1.9μM和0.37μM，分别。所提出的传感器成功地用于同时测定人尿液样品中的DA和TRP，回收率令人满意（101％至116％）。
