基于Co_(3)O_(4)@CNTs信号放大的有机磷与葡萄糖酶基传感器

Organophosphorus and glucose enzyme-based sensors based on Co_(3)O_(4)@CNTs signal amplification

利用六水合硝酸钴(Co(NO_(3))2·6H_(2)O)与对苯二甲酸(HOOC-C6H4-COOH)合成MOF-71前驱体,将其与双氰胺(C_(2)H_(4)N_(4))混合热解,得到在Co_(3)O_(4)上生长碳纳米管(CNTs)的Co_(3)O_(4)@CNTs电极修饰材料。采用扫描电子显微镜(SEM)、N2吸附-脱附曲线(BET)、X射线衍射(XRD)、X射线能谱分析(EDS)对材料进行表征。结果表明,该纳米复合材料具有丰富的孔隙结构和较大的比表面积,可增大乙酰胆碱酯酶(ACh E)和葡萄糖氧化酶(GOD)的负载量,起到信号放大的作用。电化学研究表明:MOF-71的热解及其与CNTs的复合使Co_(3)O_(4)@CNTs具有优良的导电性,也有利于信号的提升。将其分别固定ACh E和GOD,构建酶基传感器用于检测有机磷农药和葡萄糖(Glu)。检测甲基对硫磷时,其线性范围为1.0×10^(-3)~1.0 ng/mL,检出限低至0.31 pg/mL;检测对氧磷时,其线性范围为1.0×10^(-3)~1.0 ng/mL,检出限低至0.34 pg/mL;检测Glu时,其线性范围为0.1~5μmol/L和10~200μmol/L,检出限为0.04μmol/L。

Co_(3)O_(4)@CNTs electrode modification materials were obtained by mixed pyrolysis of dicyandiamide(C,H,N,)and MOF-71 precursors synthesized by cobalt nitrate hexahydrate(Co(NO_(3))_(2)·6H_(2)O)and pure terephthalic acid(HOOC-C_(3)H_(4)-COOH).The materials were characterized by scanning electron microscope(SEM),Brunner-Emmet-Teller measurement(BET),X-ray diffraction(XRD),and energy dispersive spectroscopy(EDS).The results showed that the nanocomposites had rich pore structures and large surface area,which could increase the loading of acetylcholinesterase(AChE)and glucose oxidase(GOD)for signal amplification.Meanwhile,the electrochemical performance study showed that Co_(3)O_(4)@CNTs had excellent conductivity and elevated signal due to the pyrolysis of MOF-71 and its combination with CNTs.AChE and GOD were further immobilized onto the Co_(3)O_(4)@CNTs to construct enzyme-based sensors for the detection of organophosphorus pesticides and glucose(Glu).The linear concentration ranges were 1.0×10^(-3)-1.0 ng/mL,1.0×10^(-3)-1.0 ng/mL and 0.1-5μmol/L as well as10-200μmol/L for methyl parathion detection,paraoxon detection and Glu detection,respectively,accompanied by low detection limit of 0.31 pg/mL,0.34 pg/mL and 0.04μmol/L.