The Preparation And Sensing Properties Of The Fluorescent Chemosensing Material

Fluorescence is the output signal of fluorescent chemical sensor. The fluorescent chemical sensor was widely used in analysis, analytical science, life sciences and other fields due to its good selectivity, high sensitivity and simple means of detection. Our work is focused on the design and synthesis of fluorescent chemical sensor, and carried out in two parts.The first part, we designed and synthesized a kind of oxygen sensing material. Firstly, we synthesized a kind of ruthenium complex denoted as [Ru(Phen)2Phen–Si]Cl2. It was used as fluorescent indicator and then was linked to Si-C bond of the xerogels by co-hydrolysis and co-condensation with TEOS and VTES. The number of functional groups, the performances of rigidity and polarity were reduced because of the addition of VTES. The results indicated that this sensing material had high sensitivity, good reversibility and showed good linear relationship with the concentration of oxygen, so it can be used as a good fluorescent sensing material.The second part, we designed and synthesized a kind of Hg2+ sensing material denoted as SiO₂@mSiO₂/ Py-Si. Firstly, we synthesized a core-shell mesoporous structured nanospheres denoted as SiO₂@mSiO₂. Then the fluorescent indicator pyridine derivatives (Py-Si) was covalently grafted onto the outer mesoporous silica shell. The small angle X-ray diffraction analysis confirmed the existence of mesoporous structure and the fluorescence analysis showed the sensing materials had good sensitivity, selectivity and good linear relationship with the concentration of Hg2+ between10?7 - 10?4 M. Most important, a satisfactory detection limit of 3.4×10-9 gml-1 (down to the ppb level) was obtain, which is lower 100 times than covalently grafted the same fluorescent indicator to the bulk mesoporous silica SBA-15. These results indicated that SiO₂@mSiO₂/Py-Si can be used as a wonderful fluorescent sensing material for Hg2+.