Preparation of magnetic molecularly imprinted polymers for selective adsorption of chlordiazepoxide and its determination by HPLC

Benzodiazepine drugs (BDs) belong to important and most widely used medicaments that were introduced in the 1960s [1]. They are useful for treating for as hypnotics, anxiolytic-sedative, agitation, anticonvulsive, seizures, instance anxiety, insomnia, muscle spasms and alcohol withdrawal [2]. In this study, the core-shell magnetic molecularly imprinted polymers nanoparticles (MMIPs-NP) were synthesized and then used for extraction and of chlordiazepoxide (CLD) from various samples prior to its determination by HPLC. At first, Fe3O4 nanoparticles were prepared by the coprecipitation method, stabilized with tetraethyl orthosilicate (TEOS) and functionalized with 3-(trimethoxysilyl) propyl methacrylate (MPS). Then MMIPs were synthesized under distillation conditions through precipitation polymerization of methacrylic acid (MAA) as a functional monomer, CLD as a template, ethylene glycol dimethacrylate (EGDMA) as a cross-linking agent and azobisisobutyronitrile (AIBN) as an initiator. The properties of MMIPs are characterized by fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effective variables on the extraction recovery (ER) such as the amounts of MMIP, time of adsorption, pH and volume of desorption solvent were optimized by central composite design (CCD) combined with desirability function (DF). The extraction conditions were optimized and values of variables were set as 11 mg of adsorbent, 10 min adsorption time, pH = 5.5 and 1.4 mL methanol. The linear response (r2 0.998) was obtained in the range of 0.006-10 μg mL-1 with detection limit 0.0014 μg mL-1 and ER was in the range of 90-96% with RSD 5.0% (n = 3).