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1.
Int J Mol Sci ; 12(6): 4009-20, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21747721

RESUMO

A new type of cross-linked chitosan was synthesized with Diethylene Triamine (DCCTS). The adsorption of Se (VI) on DCCTS was studied. The effect factors on adsorption and the adsorption mechanism were considered. The results indicated that the DCCTS could concentrate and separate Se (IV) at pH = 3.6; the maximum adsorption efficiency was 94%, the adsorption equilibrium time was 30 min; the maximum adsorption capacity was 42.7 mg/g; the adsorption fitted Langmuir equation. A novel method for speciation of Se (VI) and Se (IV) in environmental water samples has been developed using DCCTS as adsorbent and ICP-OES as determination means. The detection limit of this method was 12 ng/L, the relatively standard deviation was 4.5% and the recovery was 99%~104%.


Assuntos
Quitosana/química , Selênio/química , Poluentes Químicos da Água/química , Adsorção , Quitosana/síntese química , Concentração de Íons de Hidrogênio , Íons/química , Poliaminas/química , Selênio/análise , Espectrofotometria
2.
Chem Biodivers ; 4(12): 2780-90, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18081088

RESUMO

The interaction between bovine serum albumin (BSA) and tinidazole (Tindamax; 1) in aqueous solution was investigated in detail by means of UV/VIS and fluorescence spectroscopy, as well as through resonance light-scattering (RLS) spectroscopy. The apparent binding constant and number of binding sites were determined at three different temperatures, as well as the average binding distances between 1 and the nearest amino acid residue(s) of BSA, as analyzed by means of Förster's theory of non-radiation energy transfer. Compound 1 was found to quench the inner fluorescence of BSA by forming a tight 1:1 aggregate, based on both static quenching and non-radiation energy transfer. The entropy change upon complexation was positive, and the enthalpy change was negative, indicating that the observed spontaneous binding is mainly driven by electrostatic interactions.


Assuntos
Soroalbumina Bovina/química , Tinidazol/química , Animais , Sítios de Ligação , Bovinos , Estrutura Molecular , Soluções/química , Análise Espectral , Temperatura , Termodinâmica
3.
Anal Chim Acta ; 589(2): 186-91, 2007 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-17418180

RESUMO

A rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) using resonance light scattering (RLS) on an ordinary fluorescence spectrometer was developed. The viable MRSA reduced 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to produce insoluble particles which displayed intense resonance scattering light. It showed a linear relationship between the number of viable MRSA and the RLS intensity. Dead MRSA were unable to reduce MTT. MRSA exposed to flavonoids extracted from Marchantia convoluta (MCF) showed a MCF concentration-dependent inhibition of the ability to reduce MTT. The RLS could, in combination with the MTT assay, be a rapid and sensitive detection method for vitro-cultured MRSA.


Assuntos
Resistência a Meticilina , Staphylococcus aureus/isolamento & purificação , Sais de Tetrazólio/química , Tiazóis/química , Contagem de Colônia Microbiana , Flavonoides/isolamento & purificação , Luz , Espalhamento de Radiação , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta
4.
Guang Pu Xue Yu Guang Pu Fen Xi ; 27(10): 2088-92, 2007 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-18306802

RESUMO

A new method using alternating penalty trilinear decomposition algorithm coupled with excitation-emission matrix fluorometry has been developed for simultaneous resolution and determination of tyrosine, phenylalanine and tryptophan. Their correlation coefficients were 0.9987, 0.9995 and 0.9993 respectively. The contents of tyrosine, phenylalanine and tryptophan in Hibiscus syriacus L. leaves were also be determined by this method after being extracted by ultrasonic. The coefficients of variation and the recoveries of the three amino acids were 0.84%, 0.36%, 1.59% and 101.0%-92.7%, 106.5%-93.0%, 103.0%-95.0% respectively. All these show that this is a simple, fast and cridible method.


Assuntos
Fenilalanina/análise , Espectrometria de Fluorescência/métodos , Triptofano/análise , Tirosina/análise , Algoritmos , Clorexidina/análogos & derivados , Clorexidina/química , Folhas de Planta/química
5.
Anal Sci ; 22(12): 1547-51, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17159313

RESUMO

In this research, bis(2,2'-bipyridine)(4-methyl-2,2'-bipyridine-4'-carboxylic acid)ruthenium(II).2PF(6)- complex (1), was first used as a fluorescent chemosensor to recognize Cu(II) in EtOH/H(2)O (1:1, v/v) solution. The response of the sensor is based on the fluorescence quenching of complex 1 by binding with Cu(II). The analytical performance characteristics of the proposed Cu(II)-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Cu(II) with a linear range covering from 5.0 x 10(-8) to 1.0 x 10(-4) M and a detection limit of 4.2 x 10(-8) M. The experiment results show that the response behavior of 1 to Cu(II) is pH independent in medium condition (pH 4.0 - 8.0), and show excellent selectivity for Cu(II) over other transition metal cations.


Assuntos
Cobre/análise , Corantes Fluorescentes/química , Compostos de Rutênio , 2,2'-Dipiridil , Ácidos Carboxílicos , Concentração de Íons de Hidrogênio
6.
Talanta ; 70(2): 364-9, 2006 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-18970776

RESUMO

A fluorescent chemical sensor for Hg(II) using 5,10,15-tris(pentafluorophenyl)corrole (H(3)(tpfc)) as fluorophore is described in this paper. The response of the sensor is based on the fluorescence quenching of H(3)(tpfc) by coordination with Hg(II). H(3)(tpfc) based sensor shows a linear response towards Hg(II) in the concentration range from 1.2x10(-7) to 1.0x10(-4)M, with a working pH range from 5.0 to 8.0. The response time for Hg(II) concentration

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