Highly sensitive carbon paste electrode with silver-filled carbon nanotubes as a sensing element for determination of free cyanide ion in aqueous solutions

摘要

We report on newly synthesized Ag(I)-filled multiwall carbon nanotubes as a potential sensing element in ion-selective carbon paste electrodes for the determination of free cyanide in aqueous solution. The electrode was obtained by entrapping the silver-filled nanotubes into a carbon paste and displays a Nernstian response with a slope of 59.8 ± 0.3 mV decade−1, a very wide linear range (from 21.0 nM to 0.1 M of cyanide), a lower detection limit of 13.0 nM, and a response time of 2 min. The operational lifetime is up to 3 months without significant deviation in normal function.