Several Novel Fluorescent Probes Synthesis And Analytical Application

Chapter1The classification and mechnism of fluorescent probes are briefly introduced. The optical properties of quantum dots and their analytical applications have been reviewed.Chapter2Water-soluble luminescent CdSe quantum dots surface-modified with mercaptosuccinic acid (MSA-CdSe-QDs) were prepared and characterized by UV-vis and fluorescence spectroscopy, FT-IR, and TEM techniques. The results show that the sulfur atom of MSA coordinate with Cd2+ion on the QD surface and partially replaced the original oleic acid. After the MSA modification, the QDs exhibited no obvious change in shape or size. Due to the metal ion binding capability of MSA, the synthesized QDs could potentially function as a fluorescent probe for metal ions.Chapter3The sensing behavior of MSA-CdSe-QDs towards metal ions was investigated by fluorescence spectroscopy. It was found that in neutral PBS buffer solution, Cd2+enhanced the fluorescence of the QDs, whereas Cu2+exhibited a significant quenching effect on the fluorescence of the QDs. The fluorescence responses were concentration-dependent, which could be used for recognition of Cu2+ions and Cd2+in aqueous solution. The possible mechanism was also discussed.Chapter4A new fluorescent probe,4-N, N-di (2-hydroxyethyl) imino-7-nitrobenzo-2-oxa-1,3-diazole (NBD-OH) was synthesized in a single step with reasonably good yield. It was found that Vitamin B12(VB12) had the ability to quench the fluorescence of NBD-OH, and the quenched fluorescence intensity was proportional to the concentration of VB12. A method for VB12determination based on the quenching fluorescence of NBD-OH was thus established. Interference effects of various substances including sugars, vitamins, amino acids, inorganic cations and some organic substances have been studied. Under optimal conditions, the linear range is0.0-2.4×10-5M. The determination limit is8.3×10-8M. The method was applied to measure VB12injections and tablets with satisfactory results.Chapter5α-bromonaphthalene (α-BrN) has been used as a donor of triplet state energy for the acceptor camphorquinone (CQ) in y-cyclodextrin nanocavity. Intense RTP phosphorescence emission of CQ was observed in non-deoxygenated γ-CD solution. Several parameters that affect the intensity of sensitized phosphorescence have been examined. It was found that Vitamin B12(VB12) had the ability to quench the phosphorescence of CQ, and the quenched RTP intensity was proportional to the concentration of VB12. A method for VB12determination based on the phosphorescence quenching of CQ was thus established.