Optical Dual Response Detection of Iodine Based on Polymethacrylic Acid-Protected Silver Nanoclusters

A polymethacrylic acid-protected silver nanocluster with fluorescence (AgNCs@PMAA) was prepared in one step using ultraviolet light irradiation. Based on the fact that the interaction between iodine and AgNCs@PMAA could cause fluorescence quenching and characteristic absorption, a dual response method for determination of iodine by fluorescence emission spectrometry and UV-vis absorption spectrometry was established. The prepared AgNCs@PMAA was characterized by TEM, XPS and FTIR, and the results showed that the AgNCs@PMAA had uniform small nanometer size and strong fluorescence luminescence, however, the fusion effect of iodine on AgNCs@PMAA could cause changes in its composition and morphology. Based on the linear relationship between the fluorescence emission peak and absorption peak intensity change of AgNCs@PMAA and the concentration of iodine elemental substance, two methods and visual detection method for detecting iodine were established and applied to actual sample determination. The fluorescence quenching efficiency of AgNCs@PMAA was linearly correlated with I-2 concentration within the range of 1.0-90.0 mu g/mL, and the detection limit was 0.168 mu g/mL (S / N = 3). The fluorescent probe was applied to the determination of iodine in iodine tincture samples with recoveries of 100.5% - 100.9%, and the relative standard deviations were less than 4.7%. The optical probe combined with multiple detection methods showed good practical significance and application prospects.