Fe₃O₄/graphene molecularly imprinted composite for selective separation of catecholamine neurotransmitters and their...

In this study, a novel of magnetic molecularly imprinted polymers (Fe₃O₄/GO/DMIPs) with multi-targets recognizing function were prepared by surface molecular imprinting technique adopting isoprenaline as the dummy-template molecule and graphene oxide (GO) as the carrier. The morphology, structures and magnetic properties of nanosorbents were characterized and assessed in detail and the results indicated that the 3D recognition cavities and matching functional groups with catecholamine neurotransmitters (CNs) were successfully fabricated on Fe₃O₄/GO surface. Moreover, the kinetic, isothermal and selective adsorption experiments were conducted to further reveal the adsorption behavior of adsorbent toward CNs and the results showed that the Fe₃O₄/GO/DMIPs possessed high adsorption capacity, rapid binding rate and excellent selectivity for CNs. On this basis, the Fe₃O₄/GO/DMIPs were further applied as adsorbent of magnetic solid-phase extraction (MSPE) for selective recognition and separation of CNs (dopamine, epinephrine, norepinephrine) followed by UPLC-MS/MS detection. The crucial parameters affecting the extraction efficiency were systematically optimized by Box-Behnken statistical design. Under the optimum conditions, satisfactory linearity (r > 0.99) was obtained with the lower limit of quantification from 0.53 to 1.93 ng mL^-1. The accuracy (RE) ranged from -7.6% to 6.4% and the intra- and inter-day precisions were not more than 8.7% and 10.2%, respectively. Hence, the strategy proposed in this study might be used for high selectivity recognition and determination of CNs in complex biological matrices, which would provide a basis and reference for its application in the fields of separation and clinical monitoring.