Highly Sensitive and Selective Fluorescent Sensor for Ag+ in Using β-Cyclodextrin / Chitosan Polymer Coated S QDs Based on Aggregation Caused Quenching Mechanism

Abstract

A fluorometric sensor based on poly (β- cyclodextrin/chitosan) with H bonded S QDs/CTSCD nanocomposites was synthesized by self-assembly. They were characterized by FTIR, UV–Vis spectroscopy, XPS, and TEM. The S QDs on the chain of the polymer could coordinate with transition-metal ions due to surface electronegativity. The distance between the S QDs on the different chains of polymer could construct the bridge bond of S–Ag+–S with silver ions leading to fluorescence aggregation-caused quenching. The linear range of the method was from 1.0×10-5 -5.5×10−5mol/L. The correlation coefficient was 0.9992 with a detection limit of 66.7 nM. This method could be used to detect silver ions in real samples with excellent sensitivity and selectivity, indicating its potential as a novel sensor.