Preparation And Performance Of New Fluorescent Sensors For Mercury Ion

As people pay more attention to environmental protection and human heathy, it is of great significance for the detection of metal ions. Among all detecting method, the method of detecting metal ions based on fluorescent molecular sensor technology, its low detection limit and easy to operate, has received much attention. However, the application of most sensors is limited because of their low sensitivity and low sensitivity. Therefore, it is necessary to design fluorescent sensors for metal ions with higher selectivity and sensitivity.Based on the principle of fluorescence sensing and molecular recognition mechanism, three cases fluorescent sensors for mercury ion were designed and synthesized by Rhodamine B. Their performances were analyzed, such as selectivity and competition for ions, detection limit and so on. The main results are summarized as follows.1. Fluorescent nanosensor was prepared and their properties were studied.A fluorescent nanosensor?RhB-APTES-SiNPs? was developed by connecting Rh B-APTES to Si O2 nanoparticles prepared by the reverse microemulsion method. Based on the "Turn-on" mechanism, Rh B-APTES-Si NPs achieved the detection for Hg²⁺ in aqueous solution on-line, in real time and with the naked eye. Rh B-APTESSi NPs detected Hg²⁺ in aqueous solution selectively, its linear range of detection was 1⁶ ?mol/L and detection limit was 5.2 ppb.2. Turn-on fluorescent sensor was prepared and its performance was studied.Based on 2-methoxybenzophenone and Rhodamine B hydrazide,this Turn-on fluorescent sensor MR-1 for detecting Hg²⁺ was synthsized. The intensity?at 580 nm? of MR-1 increased with the concentration change of Hg²⁺ from 1 to 7 ?mol/L and its detection limit of Hg²⁺ was 6.8 ppb. MR-1 achieved the detection of Hg²⁺, high selectively and with the naked eye.3. Fluorescent sensor based on FRET and ICT was prepared and its performance was studied.With Rhodamine B and phenothiazine derivatives based, a ratiometric fluorescent sensor PR-1 basaed on FRET and ICT was builded for Hg²⁺. Its detection limit of Hg²⁺ at 1.8 ppb was achieved. With the increase of Hg²⁺ from 0.1 to 1 equivalent, the fluorescence intensity ratio?F580/F520? increased gradually. The detection limit of PR-1 is 1.8 ppb. The energy from phenothiazine was transferred to rhodamine B in the process of FRET. The Hg²⁺ respond of PR-1 was achieved by color and fluorescence changes.