[Objective] To accurately determine the components and content of fermentable sugars in wort. [Method] The components and content of fermentable sugars in wort made from degermed corn extruded at low temperature as be...[Objective] To accurately determine the components and content of fermentable sugars in wort. [Method] The components and content of fermentable sugars in wort made from degermed corn extruded at low temperature as beer adjunct were determined by HPLC. [Result] The contents of sugar components were shown as below: fructose was 3.8 g/L, glucose was 7.4 g/L, sucrose was 4.2 g/L, maltose was 53.8 g/L and maltotriose was 10.6 g/L.The content of the five fermentable sugars had good linear relation within their peak area in the determination range, the correlation coefficient was 0.977 6-0.990 7, the recoveries of samples were >96%, the standard deviation was 1.27%-3.26%. [Conclusion] The method is simple and rapid with high sensitivity and good reproducibility, it provides reliable and accurate analytic method for determining the components of fermentable sugars in wort made from degermed corn extruded at low temperature as beer adjunct.展开更多
5-Fluorouracil (5-FU) has a broad spectrum of anti-tumor activity, widely applied to the treatment of cancers. However, it is necessary to determine the plasma concentration of 5-FU in clinical practice due to its nar...5-Fluorouracil (5-FU) has a broad spectrum of anti-tumor activity, widely applied to the treatment of cancers. However, it is necessary to determine the plasma concentration of 5-FU in clinical practice due to its narrow therapeutic index. Therefore, a simple, economic and sensitive high-performance liquid chromatography (HPLC) method was developed and validated for the determination of 5-FU in human plasma. Ethyl acetate was chosen as extraction reagent. Chromatographic separation was performed on a Diamonsil C18 column (250 mm × 4.6 mm i.d., 5 μm) with the mobile phase consisting of methanol and 20 mmol/L ammonium formate using a linear gradient elution at a flow rate of 0.8 mL/min. 5-FU and 5-bromouracil (5-BU) were detected by UV detector at 265 nm. The calibration curve was linear over the concentration range of 5—500 ng/mL and the correlation coefficient was not less than 0.992 6 for all calibration curves. The intra- and inter-day precisions were less than 10.5% and 4.3%, respectively, and the accuracy was within ±3.7%. The recovery at all concentration levels was 80.1±8.6%. 5-FU was stable under possible conditions of storing and handling. This method is proved applicable to therapeutic drug monitoring and pharmacokinetic studies of 5-FU in human.展开更多
Separation of fluoxetine enantiomers on five chiral stationary phases （chiralcel OD-H, chiralcel OJ-H, chiralpak AD-H, cyclobond 1 2000 DM and kromasil CHI-TBB） was investigated. The optimal mobile phase composition...Separation of fluoxetine enantiomers on five chiral stationary phases （chiralcel OD-H, chiralcel OJ-H, chiralpak AD-H, cyclobond 1 2000 DM and kromasil CHI-TBB） was investigated. The optimal mobile phase compositions of fluoxetine separation on each column were hexane/isopropanol/diethyl amine （98/2/0.2, v/v/v）, hexane/isopropanol/diethyl amine （99/1/0. l, v/v/v）, hexane/isopropanol/diethyl amine （98/2/0.2, v/v/v）, methanol/0.2% triethylamine acetic acid （TEAA） （25/75, v/v; pH 3.8） and hexane/isopropanol/diethyl amine （98/2/0.2, v/v/v）, respectively. Experimental results demonstrated that baseline separation （Rs〉1.5） of fluoxetine enantiomers was obtained on chiralcel OD-H, chiralpak AD-H, and cyclobond I 2000 DM while the best separation was obtained on the last one. The eluate orders of fluoxetine enantiomers on the columns were determined. The first eluate by chiralcel OJ-H and kromasil CHI-TBB is the S-enantiomer, while by chiralpak AD-H and cyclobond 12000 DM is the R-enantiomer.展开更多
The chemical stability of cefixime was determined by high-performance liquid chromatography （HPLC） under different conditions, including factors such as pH, solvents, initial concentration, temperature and additives...The chemical stability of cefixime was determined by high-performance liquid chromatography （HPLC） under different conditions, including factors such as pH, solvents, initial concentration, temperature and additives. The degradation process follows the first-order kinetics. A pH-rate profile exhibits the U-shape and shows the maximum stability of cefixime at pH = 6. The stability in different pure solvents is ranked as acetone 〉 ethanol 〉 methanol 〉 water, while the degradation rate of cefixime exists a maximum at the ratio of 0.6 in water ＋ methanol mixtures. In addition, the degradation rate increases with the temperature increasing and the activation energy of degradation was found to be 27.078 kJ. mol- 1 in acetone ＋ water mixed solvents. The addition of different additives was proven to either inhibit or accelerate the degradation. The degradation products were analyzed using HPLC, LC-MS and infrared spectroscopy, and the possible degradation pathways in acid as well as alkaline environment were proposed to help us understand the degradation behavior of cefixime.展开更多
A rapid and sensitive high performance liquid chromatography-mass spectrometry （HPLC-MS） method for the quantification of nimesulide in human plasma was developed and validated. Sample aliquots of 100μL were extrac...A rapid and sensitive high performance liquid chromatography-mass spectrometry （HPLC-MS） method for the quantification of nimesulide in human plasma was developed and validated. Sample aliquots of 100μL were extracted by one-step liquid-liquid extraction after addition of hydrochlorothiazide as the internal standard （IS）. Analytes were separated on a reverse phase C18 column using methanol-water （84：16, v/v） as the mobile phase and detected by a single quadrupole mass spectrometer in selected ion monitoring （SIM） negative mode. Monitored m/z values for nimesulide and IS were 307.00 and 295.90, respectively. The overall run time was 4.2 min. Validation experiments demonstrated good precision and accuracy over a wide concentration range of 20.0-7000 ng/mL with a lower limit of quantification （LLOQ） at 20.0 ng/mL. No interference by endogenous substances or matrix effect was observed. Average extraction recoveries for nimesulide and IS were all greater than 84.4%. The assay was successfully applied to a bioequivalence study of nimesulide dispersible tablets in Chinese male volunteers after oral administration.展开更多
Safflower is a popular Chinese medicinal plant and Safflower injection is extensively used for the clinical treatment of cerebrovascular and cardiovascular diseases. In this study, HPLC-DAD-ESI-MSn was utilized to stu...Safflower is a popular Chinese medicinal plant and Safflower injection is extensively used for the clinical treatment of cerebrovascular and cardiovascular diseases. In this study, HPLC-DAD-ESI-MSn was utilized to study the stability and degradation of the two major but chemically unstable bioactive compounds hydroxysaffior yellow A and anhydrosaffior yellow B, in Safflower injection. The impact of light irradiation, temperature, and pH on the stability of these two compounds were studied. The results showed that hydroxysafflor yellow A and anhydrosafflor yellow B could degrade at high temperature （〉60 ℃） or extreme pHs （pH ≤ 3.0 or 〉7.0）, but not under light irradiation. The common degradation product was p-coumaric acid. Chemical structures of the other degradation products were characterized by LC-MS. Hypothetical degradation pathways were proposed. In addition, ADP-induced platelet aggregation tests showed that the degradation of anhydrosaffior yellow B could reduce the anticoagulation activities of Safflower injection. Our results suggest that temperature and pH are critically important for the preparation and storage of Safflower injection.展开更多
基金Supported by Shandong Natural Foundation(Y2008B10)
文摘[Objective] To accurately determine the components and content of fermentable sugars in wort. [Method] The components and content of fermentable sugars in wort made from degermed corn extruded at low temperature as beer adjunct were determined by HPLC. [Result] The contents of sugar components were shown as below: fructose was 3.8 g/L, glucose was 7.4 g/L, sucrose was 4.2 g/L, maltose was 53.8 g/L and maltotriose was 10.6 g/L.The content of the five fermentable sugars had good linear relation within their peak area in the determination range, the correlation coefficient was 0.977 6-0.990 7, the recoveries of samples were >96%, the standard deviation was 1.27%-3.26%. [Conclusion] The method is simple and rapid with high sensitivity and good reproducibility, it provides reliable and accurate analytic method for determining the components of fermentable sugars in wort made from degermed corn extruded at low temperature as beer adjunct.
基金Supported by National Natural Science Foundation of China (No. 30630075 and 20675056)Major State Basic Research Development Program of China ("973" Program) (No. 2006CB933303)
文摘5-Fluorouracil (5-FU) has a broad spectrum of anti-tumor activity, widely applied to the treatment of cancers. However, it is necessary to determine the plasma concentration of 5-FU in clinical practice due to its narrow therapeutic index. Therefore, a simple, economic and sensitive high-performance liquid chromatography (HPLC) method was developed and validated for the determination of 5-FU in human plasma. Ethyl acetate was chosen as extraction reagent. Chromatographic separation was performed on a Diamonsil C18 column (250 mm × 4.6 mm i.d., 5 μm) with the mobile phase consisting of methanol and 20 mmol/L ammonium formate using a linear gradient elution at a flow rate of 0.8 mL/min. 5-FU and 5-bromouracil (5-BU) were detected by UV detector at 265 nm. The calibration curve was linear over the concentration range of 5—500 ng/mL and the correlation coefficient was not less than 0.992 6 for all calibration curves. The intra- and inter-day precisions were less than 10.5% and 4.3%, respectively, and the accuracy was within ±3.7%. The recovery at all concentration levels was 80.1±8.6%. 5-FU was stable under possible conditions of storing and handling. This method is proved applicable to therapeutic drug monitoring and pharmacokinetic studies of 5-FU in human.
文摘Separation of fluoxetine enantiomers on five chiral stationary phases （chiralcel OD-H, chiralcel OJ-H, chiralpak AD-H, cyclobond 1 2000 DM and kromasil CHI-TBB） was investigated. The optimal mobile phase compositions of fluoxetine separation on each column were hexane/isopropanol/diethyl amine （98/2/0.2, v/v/v）, hexane/isopropanol/diethyl amine （99/1/0. l, v/v/v）, hexane/isopropanol/diethyl amine （98/2/0.2, v/v/v）, methanol/0.2% triethylamine acetic acid （TEAA） （25/75, v/v; pH 3.8） and hexane/isopropanol/diethyl amine （98/2/0.2, v/v/v）, respectively. Experimental results demonstrated that baseline separation （Rs〉1.5） of fluoxetine enantiomers was obtained on chiralcel OD-H, chiralpak AD-H, and cyclobond I 2000 DM while the best separation was obtained on the last one. The eluate orders of fluoxetine enantiomers on the columns were determined. The first eluate by chiralcel OJ-H and kromasil CHI-TBB is the S-enantiomer, while by chiralpak AD-H and cyclobond 12000 DM is the R-enantiomer.
基金Supported by the National Natural Science Foundation of China(81361140344 and21376164)National High Technology Reseach and Development Program of China(863Program,2015AA021002)Major National Scientific Instrument Development Project(21527812)
文摘The chemical stability of cefixime was determined by high-performance liquid chromatography （HPLC） under different conditions, including factors such as pH, solvents, initial concentration, temperature and additives. The degradation process follows the first-order kinetics. A pH-rate profile exhibits the U-shape and shows the maximum stability of cefixime at pH = 6. The stability in different pure solvents is ranked as acetone 〉 ethanol 〉 methanol 〉 water, while the degradation rate of cefixime exists a maximum at the ratio of 0.6 in water ＋ methanol mixtures. In addition, the degradation rate increases with the temperature increasing and the activation energy of degradation was found to be 27.078 kJ. mol- 1 in acetone ＋ water mixed solvents. The addition of different additives was proven to either inhibit or accelerate the degradation. The degradation products were analyzed using HPLC, LC-MS and infrared spectroscopy, and the possible degradation pathways in acid as well as alkaline environment were proposed to help us understand the degradation behavior of cefixime.
文摘A rapid and sensitive high performance liquid chromatography-mass spectrometry （HPLC-MS） method for the quantification of nimesulide in human plasma was developed and validated. Sample aliquots of 100μL were extracted by one-step liquid-liquid extraction after addition of hydrochlorothiazide as the internal standard （IS）. Analytes were separated on a reverse phase C18 column using methanol-water （84：16, v/v） as the mobile phase and detected by a single quadrupole mass spectrometer in selected ion monitoring （SIM） negative mode. Monitored m/z values for nimesulide and IS were 307.00 and 295.90, respectively. The overall run time was 4.2 min. Validation experiments demonstrated good precision and accuracy over a wide concentration range of 20.0-7000 ng/mL with a lower limit of quantification （LLOQ） at 20.0 ng/mL. No interference by endogenous substances or matrix effect was observed. Average extraction recoveries for nimesulide and IS were all greater than 84.4%. The assay was successfully applied to a bioequivalence study of nimesulide dispersible tablets in Chinese male volunteers after oral administration.
基金Changjiang Scholar and Innovative Research Team in University (Grant No. 985-2-063-112)Youth Research Fellowship of Chinese Center for Disease Control and Prevention (Grant No. 2009A203)
文摘Safflower is a popular Chinese medicinal plant and Safflower injection is extensively used for the clinical treatment of cerebrovascular and cardiovascular diseases. In this study, HPLC-DAD-ESI-MSn was utilized to study the stability and degradation of the two major but chemically unstable bioactive compounds hydroxysaffior yellow A and anhydrosaffior yellow B, in Safflower injection. The impact of light irradiation, temperature, and pH on the stability of these two compounds were studied. The results showed that hydroxysafflor yellow A and anhydrosafflor yellow B could degrade at high temperature （〉60 ℃） or extreme pHs （pH ≤ 3.0 or 〉7.0）, but not under light irradiation. The common degradation product was p-coumaric acid. Chemical structures of the other degradation products were characterized by LC-MS. Hypothetical degradation pathways were proposed. In addition, ADP-induced platelet aggregation tests showed that the degradation of anhydrosaffior yellow B could reduce the anticoagulation activities of Safflower injection. Our results suggest that temperature and pH are critically important for the preparation and storage of Safflower injection.
