LAUSR

Abstract A novel film consisting of ZnCdS/ZnS quantum dots (QDs) and g-C3N4 nanosheets conjugated with carboxymethyl chitosan (CMCS) chains via weak bonds was built. The Mn2+ in contact with the composite film forced the chitosan to undergo conformational changes, resulting in the intermolecular complex R–COO–(Mn2+)–NH2–R, which enhanced the fluorescence. The film was developed for trace Mn2+ determination according to the fluorescence resonance energy transfer mechanism by the enhancement effect of the film. The sensor exhibited a good linearity (F = 2.0852C + 168.667) for Mn2+ at a concentration of 1.961 × 10−6–1.667 × 10−5 mol/L under certain conditions with a correlation coefficient of 0.9981. The film was successfully used to determine Mn2+ with recoveries in the range of 90%–107% in the real water samples. The proposed method provides a simple, facile, sensitive, and fast detection method for Mn2+.