A new type of HPLC stationary phase containing thymine derivative was successfully prepared.It was found to give selective separation of nucleic acid bases and several purine derivatives,such as caffeine and theophyll...A new type of HPLC stationary phase containing thymine derivative was successfully prepared.It was found to give selective separation of nucleic acid bases and several purine derivatives,such as caffeine and theophylline.The retention behaviour and elution order of the solutes were interpreted in terms of molecular structure.展开更多
Rapid and sensitive reversed phase high performance liquid chromatography (RP-HPLC) and ultra performance liquid chromatography (RP-UPLC) method with UV detection has been developed and validated for quantification of...Rapid and sensitive reversed phase high performance liquid chromatography (RP-HPLC) and ultra performance liquid chromatography (RP-UPLC) method with UV detection has been developed and validated for quantification of parathyroid hormone (PTH) in presence of meta-cresol as a stabilizer in a pharmaceutical formulation.Chromatography was performed with mobile phase containing 0.1% Trifluoroacetic acid (TFA) in MilliQ water and 0.1% TFA in acetonitrile with gradient program and flow rate at 0.3 mL/min for HPLC and 0.4 mL/min for UPLC.Quantification was accomplished with internal reference standard (qualified against innovator product and National Institute for Biological Standards and Control (NIBSC) standard).The methods were validated for linearity (correlation coefficient 0.99),range,accuracy,precision and robustness.Robustness was confirmed by considering three factors;mobile phase composition,column temperature and flow rate/age of mobile phase.Intermediate precision was confirmed on different equipments,different columns and on different days.The relative standard deviation (RSD) (<2% for RP-HPLC and <1% for UPLC,n=30) indicated a good precision.Retention time was found about 17 min and 2 min by HPLC and UPLC methods,respectively.Both methods are simple,highly sensitive,precise and accurate and have the potential of being useful for routine quality control.展开更多
Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlatio...Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlation between the parameters of chromatograph capacity factor （CCF） and molecular structural parameters. As a result, the correlation equation of the reversed phased high performance liquid chromatograph capacity factor to the intercept lgk＇w and slope S of CCF were obtained, from which the correlation coefficients of lgk＇w to the structural parameters are r^2 = 0.9596 and q^2 = 0.9262. While the correlation coefficients of the parameter S r^2 q^2 with structures are = 0.9750 and = 0.9252. Moreover, the effect of water as solvent on the present two models was also considered using SCRF method, and the result shows that the predicting capacity of correlation equation of lgkw＇ increases, while that of the model for S decreases slightly. Both two correlation equations achieved in this work are more advantageous than those using theoretical descriptors from molecular connectivity indices.展开更多
An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction.The extraction procedure（including loading,...An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction.The extraction procedure（including loading, washing, and eluting） used a flow rate of1.0 m L/min, and dicyandiamide was eluted with 20 m L of a methanol/acetonitrile mixture（V/V = 2：3）, followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography–ultraviolet spectroscopy（HPLC–UV）. Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge（with activated carbon）.Separation was achieved on a ZIC-Hydrophilic Interaction Liquid Chromatography（ZIC-HILIC）（50 mm × 2.1 mm, 3.5 μm） chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions（R^2〉 0.999）. Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations（RSDs, n = 3） were below 6.1% with a detection limit of 5.0 ng/m L for stream water samples.展开更多
文摘A new type of HPLC stationary phase containing thymine derivative was successfully prepared.It was found to give selective separation of nucleic acid bases and several purine derivatives,such as caffeine and theophylline.The retention behaviour and elution order of the solutes were interpreted in terms of molecular structure.
文摘Rapid and sensitive reversed phase high performance liquid chromatography (RP-HPLC) and ultra performance liquid chromatography (RP-UPLC) method with UV detection has been developed and validated for quantification of parathyroid hormone (PTH) in presence of meta-cresol as a stabilizer in a pharmaceutical formulation.Chromatography was performed with mobile phase containing 0.1% Trifluoroacetic acid (TFA) in MilliQ water and 0.1% TFA in acetonitrile with gradient program and flow rate at 0.3 mL/min for HPLC and 0.4 mL/min for UPLC.Quantification was accomplished with internal reference standard (qualified against innovator product and National Institute for Biological Standards and Control (NIBSC) standard).The methods were validated for linearity (correlation coefficient 0.99),range,accuracy,precision and robustness.Robustness was confirmed by considering three factors;mobile phase composition,column temperature and flow rate/age of mobile phase.Intermediate precision was confirmed on different equipments,different columns and on different days.The relative standard deviation (RSD) (<2% for RP-HPLC and <1% for UPLC,n=30) indicated a good precision.Retention time was found about 17 min and 2 min by HPLC and UPLC methods,respectively.Both methods are simple,highly sensitive,precise and accurate and have the potential of being useful for routine quality control.
基金This work was supported by the National Basic Research Program of China (2003CB415002) and the China Postdoctoral Science Foundation (No. 2003033486) and the Natural Science Research Fund of University in Jiangsu (04KJB150149)
文摘Sixteen indole derivatives have been computed at B3LYP/6-31 IG^＊＊ level using density functional theory （DFF）. Based on linear solvation energy theory, the structural parameters were employed to present correlation between the parameters of chromatograph capacity factor （CCF） and molecular structural parameters. As a result, the correlation equation of the reversed phased high performance liquid chromatograph capacity factor to the intercept lgk＇w and slope S of CCF were obtained, from which the correlation coefficients of lgk＇w to the structural parameters are r^2 = 0.9596 and q^2 = 0.9262. While the correlation coefficients of the parameter S r^2 q^2 with structures are = 0.9750 and = 0.9252. Moreover, the effect of water as solvent on the present two models was also considered using SCRF method, and the result shows that the predicting capacity of correlation equation of lgkw＇ increases, while that of the model for S decreases slightly. Both two correlation equations achieved in this work are more advantageous than those using theoretical descriptors from molecular connectivity indices.
基金Department of Chemistry at Mississippi State University for financial support for this project
文摘An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction.The extraction procedure（including loading, washing, and eluting） used a flow rate of1.0 m L/min, and dicyandiamide was eluted with 20 m L of a methanol/acetonitrile mixture（V/V = 2：3）, followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography–ultraviolet spectroscopy（HPLC–UV）. Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge（with activated carbon）.Separation was achieved on a ZIC-Hydrophilic Interaction Liquid Chromatography（ZIC-HILIC）（50 mm × 2.1 mm, 3.5 μm） chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions（R^2〉 0.999）. Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations（RSDs, n = 3） were below 6.1% with a detection limit of 5.0 ng/m L for stream water samples.
