以铁氰根离子为电子媒介体的氧气敏感介孔电极的研究

Meso-structured cellular foam electrode confined ferricyanide ion for detection of oxygen concentration

利用介孔泡沫硅(MCF)、离子液体功能化的介孔泡沫硅(MCF-IL)为电极材料,以壳聚糖(Chit)为粘接剂,以玻碳(GC)电极为基底,制备了两种化学修饰电极MCF/Chit/GC和MCF-IL/Chit/GC,并利用静电吸附作用实现两种修饰电极对Fe(CN)6^3-的固载,固载后的电极具有电活性,可以在电极表面发生Fe(CN)6^3-/4-氧化还原反应。实验表明,Fe(CN)6^3-对溶解氧含量具有敏感的电化学响应。其中,MCF-IL/Chit/Fe(CN)6^3-/GC电极对溶解氧含量的电化学响应最佳,在体系含氧量为6.5~7.8mg·L^-1时具有明显的线性关系(r=0.9972)。MCF-IL/Chit/Fe(CN)6^3-/GC电极对氧气的良好响应得益于MCF-IL与壳聚糖之间良好的协同作用:一方面,壳聚糖对Fe(CN)6^3-具有良好的螯合能力;另一方面,MCF上所修饰的咪唑基离子液体官能团与Fe(CN)6^3-之间具有强烈的相互作用,增加了Fe(CN)6^3-的吸附量;此外,具有三维多孔结构的MCF更利于物质的传输。因此,MCF-IL/Chit/Fe(CN)6^3-/GC电极对溶解氧含量具有直接、敏感的电化学响应。

In this study, the mesostructured cellular foam (MCF) andionic liquid functionalized mesostructured cellular foam (MCF-IL) were used for the construction of modified glassy carbon electrodes. Here, chitosan (Chit) was used as the binder and the resulting electrodes were labelled as MCF/Chit/GC, MCF-IL/Chit/GC, respectively.By adsorption effect, MCF/Chit/Fe(CN)6^3- /GC and MCF-IL/Chit/Fe(CN)6^3-/GC were prepared by dipping MCF/Chit/GC and MCF-IL/Chit/GC electrodes in Fe(CN)6^3- solution, respectively. Because Fe(CN)6^3- is an effective anionic electron mediator with excellent electron transferability and a high degree of reversibility, both of these Fe(CN)6^3- -confined electrodes performed well redox electrochemical behaviour. Through adding oxygen to the system, it was found that these Fe(CN)6^3- -confined electrodes had a directly electrochemical response to the dissolved oxygen, the redox peak currents of Fe(CN)6^3-/4- on MCF/Chit/Fe(CN)6^3- /GC and MCF-IL/Chit/Fe(CN)6^3- /GC surface were shrunk. By comparison the response of oxygen at MCF/Chit/Fe(CN)6^3- /GC and MCF-IL/Chit/Fe(CN)6^3- /GC electrodes, it was found that the MCF-IL/Chit/Fe(CN)^3- 6/GC had a better linear response for oxygen concentration in range of 6.5~7.8 mg·L^-1 ( r = 0.9972). The reasons for MCF-IL/Chit/Fe(CN)6^3-/GC behaving better responses to oxygen concentration were summarized as follows: The first one is that chitosan has a good chelating ability. The second one is that the imidazolium-based ionic liquid group could adsorb more Fe(CN)6^3- because imidazolium has a strong interaction with Fe(CN)6^3- . The last one is that the mesostructured cellular foam has a three-dimensional porous structure which is of benefit to the transmission of the substrate.