Novel nano-sized dummy-surface molecularly imprinted polymers (DSMIPs) on a magnetic graphene oxide (GO-Fe3O4) surface were developed as substrates, using propionamide as a dummy template molecule for the selective recognition and rapid pre-concentration and removal of acrylamide (AM) from food samples. These products showed rapid kinetics, high binding capacity (adsorption at 3.68mg·g-1), and selectivity (imprinting factor α 2.83); the adsorption processes followed the Langmuir-Freundlich isotherm and pseudo-second-order kinetic models. Excellent recognition selectivity toward acrylamide was achieved compared to structural analogs, such as propionic and acrylic acids (selectivity factor β 2.33, and 2.20, respectively). Moreover, DSMIPs-GO-Fe3O4 was used to quantify acrylamide in food samples, yielding satisfactory recovery (86.7-94.3%) and low relative standard deviation (<4.85%). Thus, our DSMIPs-GO-Fe3O4-based procedure was demonstrated to be a convenient and practical method for the separation, enrichment, and removal of acrylamide from food samples.

Photonic-magnetic responsive molecularly imprinted microspheres (PM-MIMs) were prepared by seed polymerization, through suitable functionalization of magnetic nanoparticles for further coating with photoresponsive functional monomer and imprinted layers, and then were successfully applied to the fast and selective extraction of 17β-estradiol (17β-E2) from real samples. The PM-MIMs possessed a sandwich micro-spherical structure containing Fe3O4 core, SiO2 middle layer, and MIPs shell with thickness of 25 nm. The PM-MIMs displayed excellent photoresponsive properties and could be rapidly separated from solutions under an external magnet. The PM-MIMs had specific affinity towards 17β-E2 with high adsorption capacity (Qmax=0.84 mg g(-1)) and fast binding kinetics (Kd=26.08 mg L(-1)). The PM-MIMs proved to be an ideal photoswitch with the ability of reversible uptake and release of 17β-E2 upon alternate 365 and 440 nm irradiation: 45.0% of 17β-E2 released from the PM-MIMs upon 365 nm irradiation, and 94.0% of the released 17β-E2 was rebound to the PM-MIMs at 440 nm. Accordingly, the PM-MIMs were applied for fast separation and extraction of 17β-E2 followed by HPLC-UV determination, presenting the low limit of detection (LOD, S/N=3) and quantification (LOQ, S/N=10) of 0.18 and 0.62 μmol L(-1), respectively. The high recoveries for spiked milk powder and drinking water samples were in the range of 97.5-113.0% with relative standard deviations less than 4.4%. This study reasonably combined photonic response, magnetic separation and surface imprinting, which endowed the PM-MIMs with significant advantages of high adsorption capacity and fast binding kinetics, convenient separation and recycled use, and simple rapid eco-benign adsorption/elution processes for template molecules. Thus, the PM-MIMs based method may be a simple, rapid, convenient, cost-effective and environmentally-friendly way for simultaneous separation, enrichment and detection of trace 17β-E2 in complicated matrices.