Potentiometric Determination of Clonazepam Using Carbon Paste Electrode Based on Molecular Imprinted Polymer (MIP) in Solution and in a Biological Fluid Model

Abstract

A potentiometric method is reported for clonazepam determination in biological fluid models. A simple, rapid and sensitive method for the determination of clonazepam in biological fluid models and pharmaceutical preparations using modified carbon paste electrodes is developed. The clonazepam selective MIP was synthesized from methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linker in methanol solution using clonazepam as the template molecule and 2, 2-azobis isobutyronitrile as the initiator. A non-imprinted polymer (NIP) was prepared by the same procedure, but in the absence of template molecule then incorporated in the carbon paste electrodes (CPEs). The effect of template ratio to monomer on the sensor performance was investigated and important role for this ratio was shown. The MIP–CP electrode showed high recognition ability in comparison to NIP-CPE. Some parameters affecting the sensor response were optimized and then the calibration curve was plotted. After optimization, the carbon past electrode constructed with a MIP exhibited a Nernstian response 29.66 ± 1.0 mVdecade−1 in a wide concentration range, from 1.0×10-7 to 1.0×10-1 M, with a low detection limit of 7.3×10-7 M and the electrode showed a response time of less than 15 s. The optimum pH values for quantitative uptake of drug were 6 and it was determined by measuring the drug content in the supernatant liquid. Finally, the proposed electrode was successfully used for potentiometric determination of clonazepam in biological fluid models and pharmaceutical samples.