Magnetic molecularly imprinted polymer for the selective dispersive micro solid phase extraction of phenolphthalein in urine samples and herbal slimming capsules prior to HPLC-PDA analysis

Abstract

Magnetic molecularly imprinted polymers (MMIPs)-based dispersive micro solid phase extraction (D-µ-SPE) method have many advantages, such as high selectivity, inexpensive, simplicity, facile preparation and operation, reproducibility and environmentally friendly. In this study, a new magnetic MIP based on amino functionalized Fe3O4@SiO2 nanoparticles (NPs) was synthesized. Different characterization methods including field emission scanning electron microscopy (FESEM), Fourier transform-infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were applied for the characterization of synthesized MMIP. The proposed MMIPs-D-µ-SPE method was effectively utilized for the selective extraction of phenolphthalein from urine samples and herbal slimming capsules prior to HPLC-PDA analysis. Effect of different parameters, including the selection of pH of the sample, amount of MMIP, time of sorption, type of eluent, volume of eluent and time of elution, were examined and optimized. The maximum sorption capacity of the MMIP and MNIP were 138.2 and 68.5 mg g−1, respectively. The linearity was obtained over a wide concentration range of 0.05–10000 µg L-1 with coefficient of determination of 0.9996 and the detection limit (LOD) was found 0.01 µg L-1 (S/N = 3). The RSD values at three concentration levels (50, 250 and 500 µg L-1) ranged from 2.7% to 3.4% (intra-day, n = 5) and 4.5%-5.5% (inter-day) precision for three varied days. The present study proposed promising prospects of environmentally friendly MMIP based D-µ-SPE-HPLC-PDA method for highly efficient sample pretreatment and intended analytes determination in complex matrices.