RESUMO
A new fluorescent reagent 1,5-bis(4,6-dichloro-1,3,5-triazinylamino)naphthalene (DTAN) was synthesized. The optimum conditions of fluorescent reaction of this reagent with aniline (PA) were also investigated. Based on this reaction, a new spectrofluorimetric method was developed for the determination of aniline. The fluorescent intensity was directly proportional to the concentration of aniline in the ranges 0.05-2.0 microg mL(-1) and 2.0-50 microg mL(-1) with the detection limits of 34 ng mL(-1) and 90 ng mL(-1). This method is simple, practical and can afford good precision and accuracy and can be successfully applied to assess aniline in water samples. A possible mechanism of the change of fluorescence intensity introduced by putting the aniline into the system is also discussed.
Assuntos
1-Naftilamina/análogos & derivados , Compostos de Anilina/análise , Triazinas/síntese química , 1-Naftilamina/síntese química , 1-Naftilamina/química , Concentração de Íons de Hidrogênio , Esgotos/química , Espectrometria de Fluorescência , Temperatura , Fatores de Tempo , Triazinas/química , Água/químicaRESUMO
A new fluorescent reagent, 2-hydroxy-1-naphthaldehydene-8-aminoquinoline (HNAAQ), was synthesized. The fluorescent reaction of this reagent with mercury was also studied. Based on this chelation, a highly sensitive spectrofluorometric method was developed for the determination of trace amounts of mercury in a water-ethanol (5 + 1, v/v) medium at pH 8.0. Under these conditions, the Hg-HNAAQ complex has excitation and emission maxima at 406 and 445 nm, respectively. The linear range of the method is from 0 to 16 microg L(-1) and the detection limit is 0.056 microg L(-1) of mercury. The interference of other ions was studied. In order to enhance the selectivity in the determination of mercury by the present method, we also applied the separation of mercury by distillation. Thus, the selectivity of the method could be increased remarkably. The procedure can be easily performed, and affords good precision and accuracy. This method has been successfully applied to the determination of mercury in waste water and prawns.
RESUMO
A new spectrofluorometric method is described for the determination of metacycline (MC), based on modified enzyme-amplified lanthanide luminescence. Under the optimum conditions, Eu3+-MC forms a ternary complex with lysozyme in close proximity. Then lysozyme can remarkably enhance the characteristic fluorescence intensity of Eu3+ at 612 nm in metacycline-Eu3+ binary complex. The enhanced fluorescence intensity is in proportion to the concentration of MC. The limit of detection is 1.6 x 10(-8) mol L(-1), with a linear range from 6.2 x 10(-6) to 1.7 x 10(-5) mol L(-1). Interferences of other coexisting substances were studied. The developed method was successfully applied to the determination of MC in serum and urine samples. The mechanism of fluorescence enhancement was also studied.
Assuntos
Európio/química , Metaciclina/química , Muramidase/química , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Luminescência , Oxirredução , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , TemperaturaRESUMO
A new spectrofluorimetric method is described for the determination of doxycycline, based on modified enzyme-amplified lanthanide luminescence. Under the optimum conditions, Eu(3+)-doxycycline forms a ternary complex with lysozyme in close proximity and lysozyme can remarkably enhance the characteristic fluorescence intensity of Eu(3+) at 612nm in doxycycline-Eu(3+) binary complex. The enhanced fluorescence intensity is in proportion to the concentration of doxycycline. The limit of detection is 1.28 x 10(-8) moll(-1), with a linear range from 1.7 x 10(-7) to 1.7 x 10(-6) moll(-1). Interferences of other coexisting substances were studied. The developed method was successfully applied to the determination of doxycycline in serum, urine and real samples. The mechanism of fluorescence enhancement was also studied.
Assuntos
Doxiciclina/análise , Antibacterianos/análise , Európio/química , Humanos , Medições Luminescentes , Estrutura Molecular , Muramidase/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria de Fluorescência , Análise Espectral/métodos , Temperatura , Fatores de TempoRESUMO
The interactions between daunorubicin and human serum albumin (HSA) were studied using the spectrofluorimetric method. The binding constants of daunorubicin with HSA were obtained at different temperatures. The effects of various metal ions on the binding constants of daunorubicin with HSA were also studied. The optimum conditions of fluorometric determination of daunorubicin were studied and the developed method was successfully applied to the determination of daunorubicin in serum samples.
Assuntos
Daunorrubicina/sangue , Albumina Sérica/metabolismo , Análise Química do Sangue/métodos , Transferência de Energia , Humanos , Técnicas In Vitro , Cinética , Metais/farmacologia , Ligação Proteica/efeitos dos fármacos , Espectrometria de Fluorescência/métodos , TemperaturaRESUMO
Applying supercritical CO2 fluid extraction technology, flavonoids were extracted from Chinese traditional medicine asarum heterotropoides, atractylodes macrocephala, and rheum palmatun. Using the method of autoxidation pyrogallol (known as 325 nm method), the superoxide radical scavenging effect of the extraction was carried out in the buffer solution of HCl-tris (pH 8.2). With spectrophotometry, hydroxyl radical created by the system Co2+ + H2O2 in the reaction like Fenton reaction was eliminated by alizarin violet as the color developing agent in the buffer solution HCl-tris (pH 9.0) and the reaction condition was investigated. Result showed that these extractions are elimination agent for these radicals. Asarum heterotropoides is the best of the three.
Assuntos
Antioxidantes/farmacologia , Dióxido de Carbono/farmacologia , Cromatografia com Fluido Supercrítico/métodos , Medicamentos de Ervas Chinesas/química , Sequestradores de Radicais Livres/química , Antraquinonas , Antioxidantes/química , Atractylodes , Dióxido de Carbono/química , Cromatografia com Fluido Supercrítico/normas , Medicamentos de Ervas Chinesas/metabolismo , Sequestradores de Radicais Livres/metabolismo , Medicina Tradicional Chinesa/normas , Extratos Vegetais , Pressão , TemperaturaRESUMO
The interaction between polymyxin B sulfate and ct-DNA was studied with ethidium bromide (EB) probe by UV spectroscopy, fluorescence spectroscopy, fluorescent polarization etc. The phenomena of hyperchromism effect and fluorescence quenching proved that polymyxin B sulfate in buffer solution at pH 7.4 can intercalate into the base pairs of ct-DNA. This interaction can cause conformational change of ct-DNA double helix. This interaction can be inhibited in the presence of high concentration of ions. At the same time, PB can combine with the phosphate group of ct-DNA by non-characteristic static force. In this paper, the interaction of PB and ct-DNA was made further discussion.
Assuntos
DNA/química , Substâncias Intercalantes/química , Polimixina B/química , Interações Medicamentosas , Etídio , Corantes Fluorescentes , Espectrometria de Fluorescência/métodos , Espectrofotometria Ultravioleta/métodosRESUMO
A new fluorescent reagent, 1,5-bis(4,6-dichloro-1,3,5-triazinylamino)naphthalene, containing two active chlorines, was synthesized by a one-step reaction. Under the optimum conditions for the determination of dopamine, the enhanced fluorescence intensity is proportional to the dopamine concentration. The fluorescence intensity was measured at lambda(ex/em) = 400/460 nm, with and without dopamine. The linear range and detection limit for the determination of dopamine were 1.0 x 10(-7) mol/L-5.0 x 10(-5) mol/L and 4.0 x 10(-8) mol/L. This method is simple, practical, can afford good precision and accuracy and can be successfully applied to assess dopamine in injections and human serum samples.
Assuntos
1-Naftilamina/análogos & derivados , Dopamina/sangue , Corantes Fluorescentes/síntese química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Triazinas/síntese química , 1-Naftilamina/síntese química , Humanos , Concentração de Íons de Hidrogênio , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The interactions between tetracycline analogues (oxytetracycline, doxycycline, methacycline) and lysozyme (LYSO) were studied by using UV-visible absorption and spectrofluorimetric method. Tetracycline analogues can make LYSO's fluorescence quenching. The quenching mechanism is static quenching. Absorption spectrum and quenching constant all support this conclusion. The binding constants of tetracycline analogues with LYSO were obtained at various temperatures. According to the Förster nonradiative energy transfer theory, we can get the distances of donators and acceptors. We also determined the main acting force between them is electrostatic gravitation according to the thermodynamic parameter.