A novel p-nitroaniline fluorescent sensor based on molecular recognition of carboxymethyl-β-cyclodextrin-capped ZnO/ZnS/MgO nanocomposites.

Carboxymethyl-β-cyclodextrin (CMCD)-capped ZnO/ZnS/MgO nanocomposites, which combined water-soluble host molecules with multi-shelled nanocrystals, have been prepared. The nanocomposites have good fluorescence performance and host-guest complexation. Thus, a novel fluorescent sensor for the determination of p-nitroaniline based on the molecular recognition of water-soluble CMCD-capped ZnO/ZnS/MgO nanocomposites has been proposed. Factors affecting the p-nitroaniline detection were investigated, and the optimum conditions were determined. Under the optimum conditions, the relative fluorescence intensity of CMCD-capped ZnO/ZnS/MgO nanocomposites was linearly proportional to the concentration of p-nitroaniline over the range from 8.33 × 10−7 to 5.83 × 10−5 mol L−1 with a correlation coefficient of 0.9967 and a detection limit of 6.38 × 10−7 mol L−1. The proposed method was successfully applied to the determination of p-nitroaniline in water samples. The related mechanisms were also discussed.