4-Fluoro-7-nitrobenzo-2-oxa-1,3-diazole（NBD-F） was employed as a colorimetric probe for differential detection of biothiols in different media. The spectral response and the selectivity of NBD-F toward thiols were s...4-Fluoro-7-nitrobenzo-2-oxa-1,3-diazole（NBD-F） was employed as a colorimetric probe for differential detection of biothiols in different media. The spectral response and the selectivity of NBD-F toward thiols were significantly improved by surfactant micelles. Mercapto group exhibited high reactivity in all the solvents（including Tris–HCl buffer solution, CTAB and SDS micelles）. The 4-thioether derivatives of NBDF reacting with Cys and Hcy but not GSH could transfer to the corresponding 4-amino-substituents via intramolecular nucleophilic aromatic substitution, thus, GSH could be discriminated from Cys/Hcy. In CTAB micelles, the reaction product of NBD-F with Cys is non-fluorescent and it absorbs in longwavelength region. According to the spectral responses of NBD-F toward different low-molecularweight thiols, we could identify Cys, Hcy and GSH from each other.展开更多
Highly sensitive spectrofluorimetric method was developed and validated for the determination of gabapentin in pure and pharmaceutical preparations. The method was based on nucleophilic substitution reaction of gabape...Highly sensitive spectrofluorimetric method was developed and validated for the determination of gabapentin in pure and pharmaceutical preparations. The method was based on nucleophilic substitution reaction of gabapentin with 4-fluoro-7-nitrobenzofurazan （NBD-F） in an alkaline medium （pH 9.5） to form a highly fluorescent derivative that was measured at 521 nm after excitation at 458 rim. The factors affecting the reaction was carefully studied and optimized. The method was successfully validated for linearity, limit of detection, limit of quantification, accuracy, precision, robustness and specificity. Under the optimized conditions, linear relationship with good correlation coefficient （0.9998） was found between the relative fluorescence intensity and gabapentin concentration in the range of 10--100 ng·mL^-1. The limit of detection and limit of quantification were 0.43 and 1.30 ng·mL ^-1, respectively. The proposed method was successfully applied to the determination of gabapentin in its pharmaceutical capsules. The results obtained by the proposed method were comparable with those obtained by the official method. Statistical comparison by t- and F- tests revealed that there was no significant difference between the results of the two methods with respect to mean values and standard deviations at the 95% confidence level.展开更多
基金financially supported by Shanghai Municipal Natural Science Foundation(No.15ZR1409000)the open fund of Shanghai Key Laboratory of Chemical Biology(No.SKLCB-2013-03)
文摘4-Fluoro-7-nitrobenzo-2-oxa-1,3-diazole（NBD-F） was employed as a colorimetric probe for differential detection of biothiols in different media. The spectral response and the selectivity of NBD-F toward thiols were significantly improved by surfactant micelles. Mercapto group exhibited high reactivity in all the solvents（including Tris–HCl buffer solution, CTAB and SDS micelles）. The 4-thioether derivatives of NBDF reacting with Cys and Hcy but not GSH could transfer to the corresponding 4-amino-substituents via intramolecular nucleophilic aromatic substitution, thus, GSH could be discriminated from Cys/Hcy. In CTAB micelles, the reaction product of NBD-F with Cys is non-fluorescent and it absorbs in longwavelength region. According to the spectral responses of NBD-F toward different low-molecularweight thiols, we could identify Cys, Hcy and GSH from each other.
文摘Highly sensitive spectrofluorimetric method was developed and validated for the determination of gabapentin in pure and pharmaceutical preparations. The method was based on nucleophilic substitution reaction of gabapentin with 4-fluoro-7-nitrobenzofurazan （NBD-F） in an alkaline medium （pH 9.5） to form a highly fluorescent derivative that was measured at 521 nm after excitation at 458 rim. The factors affecting the reaction was carefully studied and optimized. The method was successfully validated for linearity, limit of detection, limit of quantification, accuracy, precision, robustness and specificity. Under the optimized conditions, linear relationship with good correlation coefficient （0.9998） was found between the relative fluorescence intensity and gabapentin concentration in the range of 10--100 ng·mL^-1. The limit of detection and limit of quantification were 0.43 and 1.30 ng·mL ^-1, respectively. The proposed method was successfully applied to the determination of gabapentin in its pharmaceutical capsules. The results obtained by the proposed method were comparable with those obtained by the official method. Statistical comparison by t- and F- tests revealed that there was no significant difference between the results of the two methods with respect to mean values and standard deviations at the 95% confidence level.
