血红蛋白/纳米金-还原氧化石墨烯复合物修饰电极对食品中亚硝酸盐的快速电化学传感检测

本文利用牛血红蛋白（hemoglobin，Hb）与纳米金-还原氧化石墨烯（gold nanoparticles-reduced Graphene Oxide, AuNPs-rGO）结合修饰的玻碳电极对亚硝酸盐进行检测，通过血红蛋白对亚硝酸根（NO2-）进行还原得到高铁血红蛋白和NO3-所产生的直接电子转移信号来对NO2-进行定性和定量的检测。将AuNPs-rGO复合物修饰在玻碳电极表面，干燥后再将Hb修饰上去形成Hb/AuNPs-rGO/GCE传感器，在上述修饰的电极上涂上80 μL浓度为0.5%的Nafion，干燥后形成Nafion膜，即形成Nafion/Hb/AuNPs-rGO/GCE传感器。通过研究发现，该电极对亚硝酸盐进行循环伏安法（cyclic voltammetry, CV）检测时有良好的选择性和灵敏度，且具有较宽的线性检测范围：0.5 μM~100 μM，峰电流与硝酸盐浓度符合线性方程：IP = 0.0369C(NO2-) + 0.2245（R = 0.9918），最低检测限为0.1 μM，该方法简单、快速、灵敏，可用于环境和食品中的亚硝酸盐的检测。
Nitrite (NO2-) was detected by a glassy carbon electrode (GCE) modified by hemoglobin (Hb) with gold nanoparticle-reduced graphene oxide (AuNPs-rGO) composite. The qualitative and quantitative detection of nitrite were conducted using the signal of a direct electron transfer generated from methemoglobin and NO3- that were produced by the redox reaction between hemoglobin and nitrite. The GCE surface was modified by AuNPs-rGO composites to produce AuNPs-rGO/GCE, which was modified by Hb after drying to form an Hb/AuNPs-rGO/GCE biosensor. After the modified electrode was coated with 80 μL of 0.5% Nafion to form a Nafion film, the Nafion/Hb/AuNPs-rGO/GCE biosensor was finally obtained. The results showed that the biosensor had good selectivity and sensitivity when cyclic voltammetry method was used to detect nitrites, with a relative wide linear range from 0.5 to 100 μM. The relationship between peak current and the nitrite concentration could be described by the linear equation of IP = 0.0369C(NO2-) + 0.2245 (R = 0.9918), and the limit of detection was 0.1 μM. This method is simple, rapid, sensitive and can be used for nitrite detection in food and environmental samples.