基于Au@ZIF-67/rGO纳米复合材料构建的电化学传感器在抗坏血酸检测中的应用

Electrochemical sensor based on Au@ZIF-67/rGO nanocomposites in the detection of ascorbic acid

先以氧化石墨烯(GO)、六水氯化钴(Ⅱ)、2-甲基咪唑为原料,在室温磁力搅拌条件下合成ZIF-67/GO纳米复合材料。再以氯金酸(HAuCl4)为原料,L-抗坏血酸(AA)为还原剂,在常温磁力搅拌条件下将Au还原到ZIF-67/GO表面,GO同时被还原为还原氧化石墨烯(rGO),从而制备Au@ZIF-67/rGO纳米复合材料。采用傅里叶变换红外光谱法(FT-IR)、场发射扫描电镜(FESEM)和X射线能谱仪(EDS)等技术对合成的材料进行表征。利用Au@ZIF-67/rGO纳米复合材料修饰玻碳电极(GCE)构建AA电化学传感器。采用循环伏安(CV)法研究了AA在Au@ZIF-67/rGO纳米复合材料修饰玻碳电极上的电化学行为。采用电流-时间(i-t)曲线法研究了检测电位、催化剂用量、pH对催化电流的影响,并确定检测AA的优化实验条件。在优化实验条件下,确定检测AA的线性范围为0.07634~7.14300 mmol/L,检测限(S/N=3)为0.03021 mmol/L。实验结果表明:Au@ZIF-67/rGO纳米复合材料对AA的氧化具有较高的电催化活性。该传感器为医学、食品、电镀、印染等领域AA的检测方法提供依据。

The ZIF-67/GO nanocomposites using graphene oxide(GO),cobalt chloride hexahydrate(II)and 2-methylimidazole as raw materials under magnetic stirring conditions at room temperature were synthe-sized firstly.Using chloroauric acid(HAuCl4)as the raw material and L-ascorbic acid(AA)as the reducing agent,Au was reduced onto the surface of ZIF-67/GO,and GO was simultaneously reduced to graphene ox-ide(rGO),thereby preparing Au@ZIF-67/rGO nanocomposites.The synthesized materials were characterized using techniques such as Fourier transform infrared spectroscopy(FT-IR),field emission scanning electron mi-croscopy(FESEM),and X-ray energy dispersive spectroscopy(EDS).AA electrochemical sensors were con-structed by using the glassy carbon electrode(GCE)modified by Au@ZIF-67/rGO nanocomposites.The electro-chemical behavior of AA on the GCE modified by Au@ZIF-67/rGO nanocomposites was studied using cyclic voltammetry(CV)method.The current time(i-t)curve method was used to studythe influence of detection potential,amount of catalyst,and pH on catalytic current,and to determine the optimized experimental condi-tions for detecting AA.Under the optimized experimental conditions,the linear range(0.07634-7.14300 mmol/L)and the detection limit(S/N=3,0.03021 mmol/L)were determined.The experimental results indicated that Au@ZIF-67/rGO nanocomposites exhibit high electrocatalytic activity for the oxidation of AA.This sensor provides a basis for the detection methods of AA in fields such as medicine,food,electroplating,printing and dyeing.