Non-electroactive Recognition: Pico-level Monitoring of Flunixin by Its Sub-second Adsorption at Au Microelectrode by Fast Fourier Transforms Continuous Cyclic Voltammetric Technique (FFTCCV)

Parviz Norouzi^a,*, Mohammad Reza Ganjali^a, Rassoul Dinarvand^b, Sharareh Labbafia
^a Center of Excellence in Electrochemistry, Department of Chemistry, University of Tehran, Tehran, Iran
^b Medical Nanotechnologycal Reserch center, University of Tehran/Medical Sciences, Tehran, Iran
E-mail: Norouzi@khayam.ut.ac.ir

Abstract
In this work a novel method for the determination of flunixin in flow-injection systems has been developed. The fast Fourier transform continuous cyclic voltammetry (FFTCV) at gold microelectrode in flowing solution system was used for determination of flunixin in its pharmaceutical formulations. The developed technique is very simple, precise, accurate, time saving and economical, compared to all of the previously reported methods. The effects of various parameters on the sensitivity of the method were investigated. The best performance was obtained with the pH value of 2, scan rate value of 30V s^–1, accumulation potential of –100 mV and accumulation time of 0.4 s. The proposed method has some advantages over other reported methods such as, no need for the removal of oxygen from the test solution, a picomolar detection limit, and finally the method is fast enough for the determination of any such compound, in a wide variety of chromatographic methods. The method was linear over the concentration range of 14–266400 pg/ml (r = 0.9975) with a limit of detection and quantitation 4 and 14 pg/ml, respectively. We used this method to determination of flunixin in tablets.

Keywords: Flunixin, ultr-amicroelectrode, fast fourier transform cyclic voltammetry, flow injection.