Morin functionalized Merrifield's resin: A new material for enrichment and sensing heavy metals

In this paper, we report the synthesis of morin covalently attached to Merrifield's resin to be used in metal sorption and recognition. The potential in sensing and sorbent properties of these materials for Cu(II), Pb(II), Zn(II) and Cd(II) in batch and using a flow-through optosensing approach is outlined. The sorption capacity was evaluated in a batch approach using atomic absorption spectroscopy. It was observed that morin modified Merrifield's resin retained all the studied metals with high efficiency (90-95%). The influence of pH on the ion binding capacity of the resin was investigated by batch method as a function of their fluorescence quenching/enhancement efficiency. The sensing properties of the morin modified beads were also evaluated by packing the resins into a flow-through cell in a FIA (flow injection analysis) format. Results demonstrated that fluorescence emission increased upon Zn2+ and Cd2+ interaction with a higher sensitivity for Zn2+. In contrast, fluorescence quenching was observed when Cu2+ and Pb2+ were injected and reacted with the resin. The potential applicability of the sensing approach for the selective determination of Cu2+ and Zn2+ ions is discussed.