Preparation of Horseradish Peroxidase Modified Gold Nanoparticle/Coiled Carbon Nanotube Nanocomposite and its application for bromate and nitrite determination

In this paper gold nanoparticles (AuNPs) were electrodeposited on the coiled carbon nanotubes (CCNTs) modified carbon ionic liquid electrode (CILE), and horseradish peroxidase (HRP) was fixed on the modified electrode by using Nafion film to get the modified electrode. HRP immobilized with AuNPs-CCNTs composite still retained the biostructure and direct electrochemistry of Nafion/HRP/AuNPs-CCNTs/CILE showed a quasi-reversible electrochemical behavior. Electrocatalysis to KBrO 3 and NaNO 2 were further checked with the apparent heterogeneous electron transfer rate constant ( ks ), the charge transfer coefficient (α) and the Michaelis-Menten constants ( K M a p p ) calculated. The linear detection range for KBrO 3 concentration was from 0.5 to 10.0 mmol·L -1 with a detection limit of 0.16 mmol·L -1 . And for NaNO 2 , the current response showed two linear sections in the concentration range from 0.1 to 0.7 mmol·L -1 and 0.9 to 3.0 mmol·L -1 with low detection limit of 0.03 mmol·L -1 . The sensor was used for the real water samples analysis with high recovery, demonstrating the practical applications.