Sobczak Agnieszka, Rębiś Tomasz, Milczarek Grzegorz
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Poznan University of Medical Sciences, 6 Grunwaldzka Str., 60-780 Poznań, Poland.
Institute of Chemistry and Technical Electrochemistry, Faculty of Chemical Technology, Poznań University of Technology, Berdychowo 4, 60-965 Poznań, Poland.
Bioelectrochemistry. 2015 Dec;106(Pt B):308-15. doi: 10.1016/j.bioelechem.2015.07.002. Epub 2015 Jul 13.
Electrocatalytic determination of NADH using a hybrid surface-modified electrode with multi-wall carbon nanotubes (MWCNTs) and a novel electrogenerated redox mediator is described. The redox mediator precursor - fluphenazine (Flu) was adsorbed on MWCNT-modified glassy carbon (GC) electrode which was then subjected to electrochemical activation in 0.1 M H2SO4 using cyclic voltammetry (CV) over a range of potentials -0.2 to 1.5 V vs. Ag/AgCl (6 scans at 100 mV s(-1)). Cyclic voltammograms of Flu indicated the formation of a stable electroactive material presenting one reversible redox couple at the formal potential of -0.115 vs. Ag/AgCl in a phosphate buffer (pH7.0) as a supporting electrolyte. The peaks increased linearly with increasing scan rate indicating electroactive molecules anchored to the electrode surface. The GC/MWCNT/Flu electrode efficiently catalyzed the oxidation of NADH with a decrease in the overpotential of about 600 mV and 150 mV compared to the bare GC and GC/MWCNT electrode, respectively. This modified electrode was successfully used as the working electrode in the chronoamperometric analysis. The peak current response to NADH was linear over its concentration range from 15 μM to 84 μM, and correlation coefficient 0.998. The limits of detection (5 μM) and quantitation (15 μM) were evaluated.
本文描述了一种使用多壁碳纳米管（MWCNTs）和新型电生氧化还原介质修饰的混合表面电极对NADH进行电催化测定的方法。氧化还原介质前体 - 氟奋乃静（Flu）吸附在MWCNT修饰的玻碳（GC）电极上，然后在0.1 M H2SO4中使用循环伏安法（CV）在相对于Ag/AgCl为 -0.2至1.5 V的电位范围内进行电化学活化（在100 mV s(-1)下扫描6次）。Flu的循环伏安图表明形成了一种稳定的电活性物质，在磷酸盐缓冲液（pH7.0）作为支持电解质的情况下，相对于Ag/AgCl的形式电位为 -0.115时呈现一个可逆的氧化还原对。随着扫描速率的增加，峰电流呈线性增加，表明电活性分子锚定在电极表面。与裸GC电极和GC/MWCNT电极相比，GC/MWCNT/Flu电极分别有效地催化了NADH的氧化，过电位降低了约600 mV和150 mV。该修饰电极成功用作计时电流分析法中的工作电极。对NADH的峰电流响应在其浓度范围从15 μM至84 μM内呈线性，相关系数为0.998。评估了检测限（5 μM）和定量限（15 μM）。
