Owing to huge cationic exchange capacity, strong accumulation ability and well-layered structure, montmorillonite has attracted much attention and been widely used in electroanalysis (Lin, Li, & Wu, 2008; Zen & Kumar, 2004). Interestingly, the adsorption capacity of montmorillonite to organic species was proven to be greatly enhanced after replacing its inorganic exchangeable cations with organic cations (Kooli, Khimyak, Alshahateet, & Chen, 2005;
Yang, Zheng, Huang, & Wu, 2008). Undoubtedly, the resulting functionalized montmorillonite exhibits higher accumulation efficiency, and enhances the detection sensitivity when it is used to construct modified electrodes.