In this study, fructose and glucose contents in honey were determined by liquid chromatography-refractive index detection method and alkaline copper tartrate solution-direct titration method. According to the results,...In this study, fructose and glucose contents in honey were determined by liquid chromatography-refractive index detection method and alkaline copper tartrate solution-direct titration method. According to the results, there were great differences between determination results of reducing sugar contents by liquid chromatography-refractive index detection method and alkaline copper tartrate solution-direct titration method. Specifically, average determination results of reducing sugar contents by liquid chromatography-refractive index detection method were reduced by about 9.5% compared with alkaline copper tartrate solution-direct titra- tion method. Subsequently, determination results of reducing sugar contents by two methods were compared and analyzed. Liquid chromatography-refractive index detection method was used to determine fructose and glucose monomers in honey, but alkaline copper tartrate solution-direct titration method was used to determine reducing sugar composition in honey, which might lead to significantly different results. Due to small sample size and limited conditions, the determination results were not necessarily representative. Bee product acquisition and processing enterprises and relevant departments should pay much attention on these issues and fully consider the current situation of grass-roots units to develop scientific, rigorous, simple, universal, convenient, low-cost and practicable standards, thus ensuring the safety and reliability of food quality.展开更多
Five phospholipids in human placenta were determined by phosphorus 31 nuclear magnetic resonance(^(31)P NMR)spectroscopy and thin-layer chromatography(TLC) scanning combined with the corrective method of absorbance pr...Five phospholipids in human placenta were determined by phosphorus 31 nuclear magnetic resonance(^(31)P NMR)spectroscopy and thin-layer chromatography(TLC) scanning combined with the corrective method of absorbance proportional coefficient. The NMR spectrometer used this investigation was a Bruker AM-500 spectrometer operating at 202.4 MHz for ^(31)P chemical shifts are relative to 85% phosphoric acid. TIC was carried out by silica gel H plate developed in chloroform-methanol-glacial acetic acid-ethanol-water(25:4:6:2:0.5),with Vaskovsky reagent as colour -developing agent of phospholipids.展开更多
Objective： To study the cerebrospinal fluid pharmacokinetics of intravenously administered high dose-methotrexate （HD-MTX） and provide a solid fundament for clinical practice. Methods： MTX at a high dose ranging f...Objective： To study the cerebrospinal fluid pharmacokinetics of intravenously administered high dose-methotrexate （HD-MTX） and provide a solid fundament for clinical practice. Methods： MTX at a high dose ranging from 1.0 to 3.0 g per course was intravenously administered to 30 patients with malignant tumors. Blood and CSF samples were consecutively collected up to 36 h after the initiation of infusion （6 h）. MTX concentrations were measured by using a reversed phase high-performance liquid chromatography （RP-HPLC） assay. Results： CSF MTX concentrations were （1.65±1.52）×10^-6, （4.3±3.34）× 10^-7, （1.46±1.10）×10^-7 and （3.19±4.38）×10^-8 mol/L, respectively, at 0, 6, 12 and 24 h post infusion, and became undetectable at 36 h post infusion. The concentration-time curve of CSF MTX closely resembled that of the plasma MTX and fitted with the following linear regression equation： Y=0.057 97＋0.010 82X （Y： CSF MTX concentration, X： Plasma MTX concentration, r=0.8357）. Conclusion： CSF MTX was metabolized in a linear two-compartment model. Additionally, pharmacokinetic analysis of MTX levels indicated a positive correlation between CSF MTX and plasma MTX levels.展开更多
A computer-assisted method is presented for optimization of multicomponent solvent mobile phase selection for separation of O-ethyl-N-isopropyl phosphoro(thioureido)thioates in reversed-phase HPLC and four geometric i...A computer-assisted method is presented for optimization of multicomponent solvent mobile phase selection for separation of O-ethyl-N-isopropyl phosphoro(thioureido)thioates in reversed-phase HPLC and four geometric isomers of pesticides Decis in normal-phase HPLC.The method is based on Snyder's solvent selection triangle concept using a statistical method.The optimization of the separation over the experimental region is based on a special polynomial esti- mation from seven experimental runs,and resolution(R_s)is used as the selection criterion.Excellent agreement was obtained between predicted data and experimental results.展开更多
文摘In this study, fructose and glucose contents in honey were determined by liquid chromatography-refractive index detection method and alkaline copper tartrate solution-direct titration method. According to the results, there were great differences between determination results of reducing sugar contents by liquid chromatography-refractive index detection method and alkaline copper tartrate solution-direct titration method. Specifically, average determination results of reducing sugar contents by liquid chromatography-refractive index detection method were reduced by about 9.5% compared with alkaline copper tartrate solution-direct titra- tion method. Subsequently, determination results of reducing sugar contents by two methods were compared and analyzed. Liquid chromatography-refractive index detection method was used to determine fructose and glucose monomers in honey, but alkaline copper tartrate solution-direct titration method was used to determine reducing sugar composition in honey, which might lead to significantly different results. Due to small sample size and limited conditions, the determination results were not necessarily representative. Bee product acquisition and processing enterprises and relevant departments should pay much attention on these issues and fully consider the current situation of grass-roots units to develop scientific, rigorous, simple, universal, convenient, low-cost and practicable standards, thus ensuring the safety and reliability of food quality.
文摘Five phospholipids in human placenta were determined by phosphorus 31 nuclear magnetic resonance(^(31)P NMR)spectroscopy and thin-layer chromatography(TLC) scanning combined with the corrective method of absorbance proportional coefficient. The NMR spectrometer used this investigation was a Bruker AM-500 spectrometer operating at 202.4 MHz for ^(31)P chemical shifts are relative to 85% phosphoric acid. TIC was carried out by silica gel H plate developed in chloroform-methanol-glacial acetic acid-ethanol-water(25:4:6:2:0.5),with Vaskovsky reagent as colour -developing agent of phospholipids.
文摘Objective： To study the cerebrospinal fluid pharmacokinetics of intravenously administered high dose-methotrexate （HD-MTX） and provide a solid fundament for clinical practice. Methods： MTX at a high dose ranging from 1.0 to 3.0 g per course was intravenously administered to 30 patients with malignant tumors. Blood and CSF samples were consecutively collected up to 36 h after the initiation of infusion （6 h）. MTX concentrations were measured by using a reversed phase high-performance liquid chromatography （RP-HPLC） assay. Results： CSF MTX concentrations were （1.65±1.52）×10^-6, （4.3±3.34）× 10^-7, （1.46±1.10）×10^-7 and （3.19±4.38）×10^-8 mol/L, respectively, at 0, 6, 12 and 24 h post infusion, and became undetectable at 36 h post infusion. The concentration-time curve of CSF MTX closely resembled that of the plasma MTX and fitted with the following linear regression equation： Y=0.057 97＋0.010 82X （Y： CSF MTX concentration, X： Plasma MTX concentration, r=0.8357）. Conclusion： CSF MTX was metabolized in a linear two-compartment model. Additionally, pharmacokinetic analysis of MTX levels indicated a positive correlation between CSF MTX and plasma MTX levels.
文摘A computer-assisted method is presented for optimization of multicomponent solvent mobile phase selection for separation of O-ethyl-N-isopropyl phosphoro(thioureido)thioates in reversed-phase HPLC and four geometric isomers of pesticides Decis in normal-phase HPLC.The method is based on Snyder's solvent selection triangle concept using a statistical method.The optimization of the separation over the experimental region is based on a special polynomial esti- mation from seven experimental runs,and resolution(R_s)is used as the selection criterion.Excellent agreement was obtained between predicted data and experimental results.
