RESUMO
A rapid, novel spectrofluorimetric method to determine epristeride (EP) in biological fluids and a pharmaceutical formulation was developed, based on the fact that fluorescence intensity of L-tryptophan could be quenched by EP in the medium of pH ? 9.0. The various factors influencing fluorescence quenching were discussed. The quenching mechanism was investigated with the quenching type, synchronous fluorescence spectra and quantum efficiency. Under the optimized conditions, fluorescence quenching value (ΔF ? FL-tryptophan-FEP-L-tryptophan) showed a good linear relationship with the EP concentration ranging from 0.4 to 12.0μg/mL. The linearity, recovery and limit of detection demonstrated that the proposed method was suitable for EP determination in biological fluids and EP tablets. The method was successfully applied to the analysis of EP in real samples and the obtained results were in good agreement with the results of the official method.
RESUMO
The β-cyclodextrin cross-linked polymer(β-CDCP) was used as adsorbent to pre-concentrate/separate the trace p-nitrophenol and then the determination was carried by UV-Vis spectrophotometry. Under alkaline condition,the adsorption/elution behavior of p-nitrophenol was studied. In 0. 02 mol/L NaOH solution and at room temperature for 30 min,the resin could separate and pre-concentrate the p-nitrophenol effectively. Methanol solution(1:1,V/V) was used as eluent and the β-CDCP could be used repeatedly. The linear range and detection limit was 0.5 -90.0 mg/L and 3. 10 μg/L,respectively. The proposed method has been used to determine the p-nitrophenol in synthesized sample with satisfactory results.