基于氧化氮掺杂石墨烯修饰碳糊电极高灵敏测定辣椒素

Highly Sensitive Determination of Capsaicin Based on Nitrogen-Doped Graphene Oxide Modified Carbon Paste Electrode

采用一步水热合成法制备氧化氮掺杂石墨烯(nitrogen-doped graphene oxide,NGO),采用X射线光电子能谱,透射电子显微镜对其进行表征。采用滴涂法制备了氧化氮掺杂石墨烯修饰碳糊电极(nitrogen-doped graphene oxide/carbon paste electrode,NGO/CPE),研究辣椒素在NGO/CPE上的电化学行为,发现与裸碳糊电极相比,NGO/CPE能显著增加辣椒素的响应信号。优化了NGO质量浓度、富集时间、介质p H值等实验参数,利用差分脉冲伏安法对辣椒素进行测定,辣椒素氧化峰电流与其质量浓度在5.0~1 200μg/L范围内呈良好线性关系,检出限为2.0μg/L(RSN=3)。将本方法用于辣椒粉样品中辣椒素含量检测,结果与比色法基本一致。

Nitrogen-doped graphene oxide（NGO） was synthesized by a one-step hydrothermal method and characterized by X-ray photoelectron spectroscopy（XPS） and transmission electron microscopy（TEM）. A NGO modified carbon paste electrode（NGO/CPE） was prepared, and the electrochemical behaviors of capsaicin at NGO/CPE were studied. Experimental results showed that the voltammetric response of capsaicin at NGO/CPE was greatly improved when compared with bare carbon paste electrode（CPE）. Some parameters such as NGO concentration, accumulation time and p H were optimized. Capsaicin was determined by using differential pulse voltammetry. Under optimal conditions, the peak current was linearly proportional to capsaicin concentration in the range of 5.0 to 1 200 μg/L, with a limit of detection（LOD） of 2.0 μg/L（RSN = 3）. The proposed method was applied for the determination of capsaicin in hot pepper samples, and the results well agreed with those obtained by colorimetry.