Multiwalled carbon nanotubes and TiO2 nanoparticles were used for the improvement of a hyoscine butylbromide (HYBB) potentiometric carbon paste electrode response. The electrode was based on the ammonium reineckate-hyoscine ion association complex as an ion-exchange site dissolved in 2-nitrophenyloctyl ether as pasting liquid. The characteristics of the suggested potentiometric nanocomposite-modified HYBB carbon paste electrode in comparison with the PVC membrane sensor show better responses in terms of sensitivity, dynamic concentration range, detection limit, Nernstain slope, low potential drift, response time, lifetime, and mechanical stability. The electrode exhibits good selectivity for HYB ion with respect to a large number of cations. For investigation of the effects of carbon nanotubes and TiO2 nanoparticles on the conductivity property of the electrode surface, electrochemical impedance spectroscopy measurements were done. The prepared electrode was successfully applied to the determination of hyoscine butylbromide in pharmaceutical formulations and biological samples.
