A Novel Magnetic Fluorescent Fe3O4@ZnS@MPS Nanosensor for Highly Sensitive Determination and Removal of Ag+

Abstract

A novel magnetic fluorescent nanoprobe (Fe3O4@ZnS@MPS(MFNPs)) was synthesized, which recognized and cooperated with Ag+ ions, and a rapid method for detecting Ag+ was established in solution. It was found by fluorescence spectroscopy analysis that the MFNPs could detect Ag+ in PBS solution and, upon addition of Ag+ ions, the fluorescence (FL) of MFNPs could be quenched significantly. The sensor has a low limit of detection (LOD) of 7.04 µM for Ag+. The results showed that MFNPs were extremely specific and sensitive for the quantitative detection of Ag+ over a wide pH range. Then, the recognition mechanism between MFNPs and guest Ag+ was explored via measures of infrared spectroscopy and electron microscopy. It was speculated that the oxygen atoms in the sulfonic acid group cooperated with Ag+ to form a synergistic complexation. The assay was successfully used to determine the content of Ag+ in real samples.