Selective separation and determination of diclofenac via magnetic molecularly imprinted polymer and spectrophotometry

A simple, rapid and selective method for the separation/preconcentration and determination of diclofenac (DFC) based on the combination of extraction with the magnetic molecularly imprinted polymer (MMIP) and analysis via fiber optic-linear array spectrophotometer was developed. MMIP were prepared by precipitation polymerization, using SiO2-coated Fe3O4 nanoparticles as the magnetic components, DFC as the template molecule, 4-vinylpyridine (4-VP) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross linker. The synthesized MMIP characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The main parameters affecting the extraction recoveries including the type and volume of desorption solvent, desorption time, sample pH, and extraction time were optimized. The highest extraction recovery (>98 %) was obtained by a mixture of the methanol and acetic acid (9: 1, v/v) as the eluting solution. The Scatchard plot analysis indicates the formation of two classes of binding sites with the maximum capacity of 44.11 and 116.35 mg g(-1). Under the optimum conditions, the calibration graph was linear (r(2) = 0.9994) in the range of 1-50 mu g L-1 with a detection limit of 0.23 mu g L-1 for the preconcentration of 100 mL of the sample and 0.5 mL of the eluent. This method was successfully applied to the determination of DFC in water samples, human blood serum, urine sample and pharmaceutical ampoules.