Determination of Cloxacillin Residues using Design and Development of the Electrochemical Nanosensor based on Molecular Imprinted Polymer

Cloxacillin is an antibiotic useful for the treatment of a number of bacterial infections. It is semisynthetic and in the same class as penicillin [1]. Numerous Methods have been described for determination of Cloxacillin in food samples by Reversed-Phase High-Performance Liquid Chromatography, FT-NIR spectroscopy and electrochemistry. Electrochemical analysis is more attractive due to its simplicity, high sensitivity, fast response and relatively low cost [2]. On the other hand, molecularly imprinted polymers (MIPs) are tailor made materials with selective recognition properties toward a chosen guest molecule or related compounds similar to that displayed by antibodies but without their experimental restrictions. These materials are prepared by the polymerization of a suitable monomer and a cross-linker agent in the presence of a template molecule [3]. Since, the application of electropolymerization for synthesis of MIP to determination of cloxacillin residues in milk and animal tissue has not previously been reported. The aim of this work is development a procedure for separation and determination of Cloxacillin in dairy products based on electropolymerization of aniline layer on carbon ceramic electrode for creation of MIP. Firstly, a multiwall carbon nanotube modified carbon ceramic composite was prepared via sol gel. Next, presented composite was prepared into carbon ceramic electrode. The surface electrodes were coated with electropolymerization by a layer of molecular imprinted polymer from polyaniline. Electropolymerization was preformed out in presence of Cloxacillin through applying potential in range of -0.2 to 1.1 V, at scan 6 cycles. The specialty site for Cloxacillin was created in surface after extraction of Cloxacillin inside polymeric matrix. The 391 morphology of electrode coated with molecular imprinted polymer was studied by scanning electronic microscopy (Fig 1). Separation and determination of accumulated Cloxacillin on surface electrode was optimized by changing parameters include pH solution, accumulation time and temperature. The high anodic signal was obtained when presented nanosensor was allocated in solution include 1.0 mM Cloxacillin and 0.1 M phosphate buffer with pH= 3.8 and 35 °C for 95 min. a b Fig 1. SEM images of electropolymerized electrode (a) in absence and (b) in presence of Cloxacillin The electrochemical behavior of proposed sensor was evaluated in different concentration of Cloxacillin, which their DPVs depicted in Fig 2 and its linear range and detection limit obtained 120 – 600 nM and 48.0 nM, respectively. Fig 2: Differential pulse voltammograms of MIP/MWCNT/CCE in a 0.1-M phosphate-buffered solution (pH 7.0) containing different concentrations of Cloxacillin. Insets show the plots of the electrocatalytic peak current as a function of Cloxacillin concentration in the range of 120–600 nM