Determination of quercetin using a molecularly imprinted polymer as solid-phase microextraction sorbent and high-performance liquid chromatography

A novel sorbent for solid-phase microextraction (SPME) based on molecularly imprinted polymers (M1Ps) was developed to determine of quercetin by high-performance liquid chromatography-UV detection (HPLC-UV). Sol-gel process as a simple method was used to prepare the sorbent. The combination of MIP and SPME increased the selectivity and stability of the SPME fiber. First, stainless steel (SS) wires were modified and then M1Ps synthesized through a sol-gel method using 3-aminopropyltriethoxysilane (APTES) as a functional monomer and tetraethyl orthosilicate (TEOS) as a cross link agent The prepared MIP was characterized by field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Influential parameters on extraction efficiency were investigated and optimized. The maximum extraction efficiency was obtained under the optimum conditions including: pH 4.5, extraction time 30 min, stirring rate 500 rpm, desorption time 20 min and MeOH/AcOH (9:1 V/V) as a desorption solvent The proposed method was found to be linear for the concentration range from 0.05 to 100 mu g mL(-1) with R-2 = 0.9998. The limit of detection (LOD) was 9.94 ng mL(-1). Relative standard deviations (RSD) (n = 6) using a single fiber and between fibers were 2.3 and 5.0%, respectively. The proposed MIP-SPME fiber was successfully applied for selective determination of quercetin in tea and coffee samples.