Abstract
An electrochemical detection technique based on combination of was coulometric differential fast Fourier transformation admittance voltammetry (CDFFTAV) and nano-composite film modified glassy carbon electrode was successfully applied for sensitive determination of Amlodipine. The nano-composite film was made by a mixture of ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4), multiwall carbon nanotube and Au nanoparticles as electrochemical mediators. Studies reveal that the irreversible oxidation of Amlodipine was highly facile on the electrode surface. The electrochemical response was established on calculation of the charge under the admittance peak, which was obtained by discrete integration of the admittance response in a selected potential range, obtained in a flow injection analysis. Once established the best operative optimum conditions, the resulting nano-composite film electrode showed a catalytic effect on the oxidation of the analyte. The response is linear in the Amlodipine concentration range of 1.0 x 10(-9) to 2.0 x 10(-7) M with a detection limit of 1.25 x 10(-10) M. Moreover, the proposed technique exhibited high sensitivity, fast response time (less than 6 s) and long-term stability and reproducibility around 96%, and it was successfully used to the determination of Amlodipine content in the pharmaceutical formulation. (C) 2014 Elsevier B.V. All rights reserved.