Preparation of a novel fluorescence nanoparticles and its application in the determination of Hg(II).

The strong fluorescence 2-vinylnaphthalene and acrylic acid polymer nanoparticles have been prepared under ultrasonic radiation. Based on the fluorescence quenching of polymer by Hg(II), a method for the selective determination of Hg(II) was developed. The reaction conditions between Hg(II) and polymer were investigated in detail. The assay is very few interference stable fluorescence signals (at least 2h), simple instrument (common spectrofluorometer) and simple step. Under optimal experimental conditions, a limit of detection of 0.01 microg ml(-1) was achieved. The calibration curve was linear over the concentration range 0.04-0.1 microg ml(-1) with a correlation coefficient of 0.9927. The proposed method has been applied to the selective quantification of Hg(II) in synthetic samples with the satisfactory results.

Using organic nanoparticle fluorescence to determine nitrite in water.

Organic fluorescence nanoparticles (1-aminopyrene nanoparticles) were prepared under ultrasonic radiation and used to determine nitrite. Such nanoparticles have a broad, continuous excitation spectrum, but they are also photochemically stable and water-soluble. Nitrite determination was based upon nitrite quenching the fluorescence of the nanoparticles due to a simple diazotization reaction; a simple and specific method. Under optimal conditions, the linear range of the calibration curve was 20-1400 ng ml(-1), with a correlation coefficient of 0.9987 for nitrite. The detection limit was 3 ng ml(-1). The method was applied to various water samples from several sources. Quantitative nitrite recoveries and satisfactory results were achieved.

[Spectroscopic studies of interaction of brilliant cresyl blue and DNA].

The interaction of dye brilliant cresyl blue (BCB), which features a phenoxonium group, with hydroxypropyl-beta-cyclodextrinl and DNA in aqueous solution was studied by spectroscopic methods. The experimental results indicate that BCB can be included into the hydrophobic cavity of HP-beta-CD to form an inclusion, a complex with a stability constant of 1.98 x 10(3) L x mol(-1). At low DNA concentrations, BCB can be bound to DNA to form a 1:1 association complex with the binding constant of 4.3 x 10(4) mol x L(-1), and the major binding model of BCB to DNA is "electrostatic binding". However, the major binding model changes to "intercalative binding" at high DNA concentrations. In addition, the interactions of BCB-(HP-beta-CD) inclusion complex and DNA have been investigated. The results suggest that BCB displayed a high affinity for DNA and the inclusion complex decomposed when it was bound to DNA.