Fabrication of an Electrochemical Sensor Based on Molecularly Imprinted Polymer for the Selective Determination of Clonazepam in Various Samples: Study of the Modifier Effect

In this research, a modified carbon paste electrode (CPE) has been constructed for the electrochemical determination of clonazepam (CLZP) in different real samples. Different modifiers including multi-wall carbon nanotube (MWCNT) molecularly imprinted polymer (MIP) as magnetic and non-magnetic modifiers are used for the surface modification. The characterization of the as-synthesized MIP was carried out using Fourier transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM), simultaneous thermal analysis (STA), and Brunauer-Emmett-Teller (BET). It was found that the MIP was found to be a selective modifier to design a CLZP sensor, in an electrocatalytic process. To investigate the electrochemical behavior of the sensor and determination of CLZP, the cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were applied, respectively. The effect of some parameters on sensor response such as pH, MIP percentage, and scan rate was studied and optimized. Under optimum conditions (pH=۷, scan rate of ۵۰ mV.s-۱), a linear range from ۱.۶۴ to ۷۲.۳ μM, a detection limit of ۰.۲۶ μM (۳Sb/m; N=۵), and quantification limit (LOQ) of ۰.۸۷ μM was obtained. Besides, compared to the non-imprinted polymer sample (NIP), MIP modified-CPE (MIP/CPE) showed good sensitivity toward the CLZP drug. The prepared sensor was used to determine the CLZP drug in different real samples such as drinking water, urine, blood, and tablets.