Improvement of Carbon Paste Ion Selective Electrode Response by Using Room Temperature Ionic Liquids (RTILs) and Multi-Walled Carbon Nanotubes (MWCNTs)

Abstract

In this work by using room temperature ionic liquids (RTILs) and multi-walled carbon nanotubes (MWCNTs), response of a cerium carbon paste potentiometric sensor was modified. A room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate, [bmim]BF4, was tested as binder for construction of the carbon paste electrode. The characteristics of these electrodes as potentiometric sensors were evaluated and compared with those of the traditional carbon paste electrode (CPE). The results indicate that potentiometric sensor constructed with ionic liquid shows an increase in performance in terms of Nernstian slope, selectivity, response time, and response stability compared to CPE. This sensor with the membrane composition of 25% [bmim] BF4, 16% NHMF, 44% graphite powder and 15% MWCNT, exhibits a rapid and good Nernstian response toward Ce(III) ions in the range of 8.0×10-7-1.0×10-1 M with a slope of 19.9±0.2 mV per decade and a detection limit of 3.6×10-7 M. The sensor can be used in a pH range from 3.5 to 9.0.