Carboxymethyl chitosan crosslinked ꞵ-cyclodextrin containing hydrogen bonded NC QDs nanocomposites to design fluorescence probes for manganese ion (II) sensing.

Abstract The direct determination Mn2+ using carboxymethyl chitosan crosslinked with cyclodextrin containing hydrogen-bonded N C QDs (N C QD/CCSCD nanocomposites). The probable mechanism of the N C QD/CCSCD nanocomposites' fluorescence was quenched by Mn2+ could be interpreted as acyclic crown ether chelation. Mn2+ induced the N C QD/CCSCD clusters assembly to form large aggregates, which resulted in aggregation-caused quenching. The linear detection (I = 479.93–15.94C (R2 = 0.9954)) can be established at Mn2+ concentrations from 0 to 21.11 × 10−6 mol/L. Common metal ions, except iron and magnesium, showed minimal effect on detection. It could satisfy the standard range of Mn2+ in actual water samples. The method which using chelating assembly mechanism to build a novel sensor would provide a new model for the application of polymer materials in this field, but the precise assembly of polymer is an unsolved challenge.