Synthesis of a nano molecularly imprinted polymeric sorbent for solid phase extraction and determination of phenytoin in plasma, urine, and wastewater by HPLC

Abstract

In this work a nano polymeric sorbent for phenytoin was synthesized by non-covalent molecularly imprinted polymerization approach. We used a new mix solvent of ethanol and acetonitrile as porogen for phenytoin imprinted polymer synthesis via the precipitation method. Acrylamide and ethylene glycol dimethacrylate were used as functional monomer and crosslinker respectively. The effect of two different amounts of porogen on binding ability and thermal stability of MIP was investigated. Results indicated that increasing the porogen amount made MIP with higher thermal stability and binding efficiency. The polymers were fully characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) analyses. Then, they were evaluated by studying effect of the pH, time, and phenytoin concentration on their extraction ability in aqueous solutions. Molecularly imprinted polymer (MIP) showed high extraction capacity of >18 000 μg g⁻¹ for phenytoin molecule. Determination of phenytoin in plasma, urine, and wastewater was performed by coupling MIP as solid phase extraction (SPE) with a partially modified high performance liquid chromatography (HPLC). Analysis was performed in t < 6 min in isocratic mode on a reversed phase C₁₈ column (5 μm; 150 × 4.6 mm) using a mobile phase composed of acetonitrile-buffer phosphate 0.01 M (50 : 50, v/v) adjusted to pH of 6.0, at flow rate of 0.5 mL min⁻¹ and UV absorbance at 210 nm. The calibration curve showed good linearity in 2–30 μg mL⁻¹ range. The limit of detection (LOD) and limit of quantification (LOQ) values were 0.7 μg mL⁻¹ and 2 μg mL⁻¹ respectively. The results showed that the method could be successfully applied for the determination of phenytoin in aqueous and biological samples.