Fast exhaustive enrichment and electrochemical quantitative detection of anthocyanins from natural products by using dual responsive and dummy molecularly imprinted polymers

In this work, a new adsorbent was synthesized using dummy-template molecular imprinting technology, magnetic separation technology and pH-responsive technology, which was used to quickly enrich anthocyanins in fruit and detect with electrochemical methods. On the surface of magnetic particles, the molecularly-imprinted materials were synthesized by using quercetin as the dummy-template, 4-vinyl phenylboronic acid and methacrylic acid as the functional monomers. The microstructure was characterized by scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy, N2 adsorption-desorption, thermal gravimetric analysis, vibrating sample magnetometer and X-ray photoelectron spectroscopy. Compared with structural analogue, dummy-template magnetic and pH-responsive molecularly imprinted polymers (DMMIPs) had shorter kinetic equilibrium time, higher selectivity and better adsorption capacity toward anthocyanins. The binding capacity and imprinting factor of the dummy molecularly imprinted polymer could reach 59.22 mg/g and 1.56, respectively. The anthocyanins' content of blueberry and grape peel crude extracts were consistent with the reference reports.