As an important constituent of Glycyrrhiza uralensis Fisch.,glycyrrhetinic acid has been widely used in Chinese traditional medicine.In order to improve its water solubility and bio-avalability and to reduce its side ...As an important constituent of Glycyrrhiza uralensis Fisch.,glycyrrhetinic acid has been widely used in Chinese traditional medicine.In order to improve its water solubility and bio-avalability and to reduce its side effects,a new derivative of glycyrrhetinic acid,arginine glycyrrhetinate,was synthesized by the reaction of 18β-glycyrrhetinic acid with L-arginine.The chemical composition and structure of this new compound were determined by a series of spectral technology,including MS,NMR,UV and IR spectroscopy.This study will be useful to identification of compounds with similar structure and also be helpful to quality control during drug production.展开更多
A hydride generation Fe(Ⅱ) 1,10 phenanthroline spectrophotometric method was established for the determination of selenium in seafoods.After digested in mixture of sulfuric,nitric and perchloric acids,selenium in the...A hydride generation Fe(Ⅱ) 1,10 phenanthroline spectrophotometric method was established for the determination of selenium in seafoods.After digested in mixture of sulfuric,nitric and perchloric acids,selenium in the sample was transformed to selenite and separated from coexistent elements by solvent extraction with benzene and re extraxtion with water.The hydride of selenium was generated by reduction with 3% NaBH 4 from the extract solution containing 2 mol/L of HCl and absorbed in Fe(Ⅲ) 1,10 phenanthroline solution,whose absorbency was measured at 510nm after reduction.The apparent molar absorptivity for selenium is 5.9×10 4L·mol -1 ·cm -1 and the linear range is within 0～20μg.The method is characteristic of its high sensitivity,strong selectivity and convenient operation.Total selenium in four high grade seafood samples inshore Yantai has been determined with RSD<6% and coverage within 92～103%.展开更多
An orthogonal-design experiment with the type of L9(34) is applied to optimize the condition for sulfonation of andrographolide with concentrated sulfuric acid.The optimal sulfonation condition is established by gener...An orthogonal-design experiment with the type of L9(34) is applied to optimize the condition for sulfonation of andrographolide with concentrated sulfuric acid.The optimal sulfonation condition is established by general analysis of reacting percentage of sulfonation agent and the yield of main aim product with multi-target grading method.The multi-target grade is significantly affected by the weight ratio of concentrated sulfuric acid to andrographolide,whereas reaction time and concentration of the alkali used for neutralization have insignificant effect.The optimal condition is established as concentrated sulfuric acid reacting with half weight of andrographolide for 72 h and then neutralized by sodium hydroxide with a weight concentration of 30%.展开更多
文摘As an important constituent of Glycyrrhiza uralensis Fisch.,glycyrrhetinic acid has been widely used in Chinese traditional medicine.In order to improve its water solubility and bio-avalability and to reduce its side effects,a new derivative of glycyrrhetinic acid,arginine glycyrrhetinate,was synthesized by the reaction of 18β-glycyrrhetinic acid with L-arginine.The chemical composition and structure of this new compound were determined by a series of spectral technology,including MS,NMR,UV and IR spectroscopy.This study will be useful to identification of compounds with similar structure and also be helpful to quality control during drug production.
文摘A hydride generation Fe(Ⅱ) 1,10 phenanthroline spectrophotometric method was established for the determination of selenium in seafoods.After digested in mixture of sulfuric,nitric and perchloric acids,selenium in the sample was transformed to selenite and separated from coexistent elements by solvent extraction with benzene and re extraxtion with water.The hydride of selenium was generated by reduction with 3% NaBH 4 from the extract solution containing 2 mol/L of HCl and absorbed in Fe(Ⅲ) 1,10 phenanthroline solution,whose absorbency was measured at 510nm after reduction.The apparent molar absorptivity for selenium is 5.9×10 4L·mol -1 ·cm -1 and the linear range is within 0～20μg.The method is characteristic of its high sensitivity,strong selectivity and convenient operation.Total selenium in four high grade seafood samples inshore Yantai has been determined with RSD<6% and coverage within 92～103%.
文摘An orthogonal-design experiment with the type of L9(34) is applied to optimize the condition for sulfonation of andrographolide with concentrated sulfuric acid.The optimal sulfonation condition is established by general analysis of reacting percentage of sulfonation agent and the yield of main aim product with multi-target grading method.The multi-target grade is significantly affected by the weight ratio of concentrated sulfuric acid to andrographolide,whereas reaction time and concentration of the alkali used for neutralization have insignificant effect.The optimal condition is established as concentrated sulfuric acid reacting with half weight of andrographolide for 72 h and then neutralized by sodium hydroxide with a weight concentration of 30%.
