Functionalized carbon nanotubes-With silver nanoparticles to fabricate a sensor for the determination of zolmitriptan in its dosage forms and biological samples

A simple, sensitive and reproducible silver nanoparticle/multi walled carbon nanotubes modified glassy carbon electrode was developed as a sensor for the voltammetric determination of zolmitriptan with good accuracy and precision. The electrochemical behavior of zolmitriptan was investigated in detail using the proposed modified glassy carbon electrode. The results showed that the modified electrode significantly enhanced the oxidation peak current of zolmitriptan. Experimental conditions, such as pH, scan rate, accumulation time and potential, amount of silver nanoparticle and functionalized multi walled carbon nanotubes on the glassy carbon electrode were optimized for zolmitriptan assay. Under optimum conditions, the voltammetric determination of zolmitriptan was performed between the linear range of 1.00 x 10(-8) and 8.00 x 10(-7) M with a detection limit of 1.47 x 10(-9) M. The developed method was successfully applied to the determination of the drug in tablets and human urine samples with good recoveries. The detection limit was found as 2.08 x 10(-9) M for zolmitriptan in urine samples with a linear range of 1.00 x 10(-8) to 1.00 x 10(-7) M. No electroactive interferences from the tablet excipients and endogenous substances from biological material were found. The possible electrooxidation pathway and the number of transferred electrons were investigated in detail. Also, controlled potential coulometric experiments were carried out. (C) 2013 Elsevier B.V. All rights reserved.