A sensitive electrochemical sensor determination of dopamine (DA) has been developed using the polymerized L-tryptophan (p-L-Trp) and graphene (GN) composite as the electrode. The sensor electrode is fabricated by electrochemical polymerization of L-Trp on the GN-modified glassy carbon electrode. The composite sensor electrode shows an excellent electrochemical catalytic activity towards DA oxidation. The oxidation current is recorded by differential pulse voltammetry. The peak oxidation current is in logarithmically proportion to the DA concentration in a range from 0.2 to 100 μM with a detection limit of 0.06 μM. The detection selectivity is also carried out in the presence of ascorbic acid with a high concentration. The sensor is successfully applied for detecting DA in dopamine hydrochloride injection in real samples. The success of the sensor in DA detection is ascribed to a synergetic effect and π–π stacking interaction of GN and p-L-Trp.

使用聚合的L-色氨酸（pL-Trp）和石墨烯（GN）复合材料作为电极，已经开发出灵敏的电化学传感器测定多巴胺（DA）的方法。传感器电极是通过L-Trp在GN改性玻璃碳电极上的电化学聚合反应制成的。复合传感器电极对DA氧化具有出色的电化学催化活性。通过差分脉冲伏安法记录氧化电流。氧化峰值电流与DA浓度成对数比例，范围为0.2至100μM，检测极限为0.06μM。检测选择性也可在高浓度抗坏血酸存在下进行。该传感器已成功应用于检测真实样品中盐酸多巴胺注射液中的DA。