聚甲苯胺蓝-(多壁碳纳米管/PDDA)_n杂化膜修饰印刷电极的制备及其对NADH的测定

利用静电层层组装的方式在印刷电极表面制备了(多壁碳纳米管/邻苯二甲酸二乙二醇二丙烯酸酯(PDDA))n多层膜,采用电位扫描电聚合法在修饰有多层膜的印刷电极表面聚合甲苯胺蓝,制备了聚甲苯胺蓝-(多壁碳纳米管/PDDA)n杂化膜修饰电极。扫描电镜实验表明,多壁碳纳米管均匀分布在杂化膜中,且多壁碳纳米管的掺杂使杂化膜表现出明显的多孔性。电化学实验表明,杂化膜具有良好的导电性且多壁碳纳米管的掺杂显著增加了聚甲苯胺蓝在电极表面的担载量,提高了检测灵敏度。在pH7.4的磷酸盐缓冲液中,杂化膜修饰电极对β-烟酰胺腺嘌呤二核苷酸(NADH)的氧化具有良好的催化作用,与裸电极相比氧化电位降低了560 mV,灵敏度明显提高。在8.7×10-8~1.3×10-4mol/L范围内,NADH的浓度与氧化电流呈线性关系,检出限为2.8×10-8mol/L,该修饰电极可用于NADH的测定。

Electropolymerization of Toluidine Blue into Multilayer Carbon Nanotube and PDDA on Screen-printed Electrode for Sensitive Detection of NADH

An electrochemical sensing platform was developed for the amperometric detection of β-nicotinamide adenine dinucleotide(NADH) via electrooxidative polymerization of toluidine blue into a multiwalled carbon nanotubes(MWCNTs)/poly(diallyldimethylammonium chloride) (PDDA) multilayer constructed by electrostatic layer-by-layer assembled onto a screen-printed electrode.Electrochemical techniques and scanning electron microscopy(SEM) were used to demonstrate that the porous composite was formed on the surface of the electrode and carbon nanotubes served as nanosized backbone for loading the polymeric toluidine blue.Compared with the pure poly(toluidine blue) modified electrode, the sensitivity of the hybrid film modified electrode was improved for the determination of NADH.In phosphate buffer solution(pH=7.4),the electrocatalytic current for NADH oxidation was enhanced with the increase of the number of layers.The assembled amount on the electrode surface of the CNTs increased significantly, thus leading to the increase of effective electrode area and the increase of the loading amount of poly(toluidine blue) on the electrode surface.Compared with the bare electrode, the oxidation potential was reduced by 560 mV, and the sensitivity increased significantly.Under the optimal condition, a linear range of 8.7×10~(-8)-1.3×10~(-4) mol/L NADH and a detection limit of 2.8×10~(-8) mol/L for NADH were obtained.Thus the(MWCNTs/PDDA)n-poly(toluidine blue) hybrid film on screen-printed electrode can be used for the detection of NADH.