Synergistic-Effect-Controlled Tetraoctylammonium Bromide/Multi-Walled Carbon Nanotube@ Hemin Hybrid Material for Construction of Electrochemical Sensor

For improving the stability of the modified interface and response sensitivity, synergistic effect of a cationic surfactant of tetraoctylammonium bromide (TOAB), carboxylic acid functionalized multi-walled carbon nanotube (MWCNT) and Hemin was used to fabricate a novel non-enzyme electrochemical sensor. TOAB as an ion-pair reagent interacts with carboxyl groups on MWCNT and Hemin to reduce electrostatic repulsion and improve the pi-pi stacking interaction between MWCNT and Hemin, which were proved by UV-vis spectrophotometry and electrochemical technique. Moreover, TOAB matrix provided a hydrophobic surrounding required for reversible electrochemical redox of Hemin on a glassy carbon electrode (GCE) in aqueous solution. MWCNTfurther promoted the electron transfer between Hemin and electrode surface. Consequently, the proposed sensor based on TOAB/MWCNT@Hemin/GCE exhibited higher response sensitivity comparing with those of TOAB/Hemin/GCE and MWCNT@Hemin/GCE. Using hydrogen peroxide (H2O2) as a target analyte for evaluating the performance of the sensor, a high sensitivity of 1.37 mu A mu M-1 cm(-2) and low limit of detection (LOD) of 0.26 mu M were obtained on the TOAB/MWCNT@Hemin/GCE in a linear range from 0.82 to 278.6 mu M. The rapid, simple, stable, and sensitive sensing platform supplies great promising applications in electrochemical analysis and paves a new avenue for constructing the non-enzyme electrochemical sensor. (C) 2017 The Electrochemical Society. All rights reserved.