A quick, efficient and environmentally beneficial approach for the extraction of alkaloids in goldenseal based on pressurized hot water extraction (PHWE) is presented. PHWE was evaluated following the extraction of hy...A quick, efficient and environmentally beneficial approach for the extraction of alkaloids in goldenseal based on pressurized hot water extraction (PHWE) is presented. PHWE was evaluated following the extraction of hydrastine and berberine which are the two main alkaloids of goldenseal. The effects of temperature and other parameters on extraction yields were monitored by high performance liquid chromatography coupled to diode array detector (HPLC-DAD). The extraction yields were compared to those achieved through reflux and ultrasonic extraction methods. PHWE employed hot water at an optimal temperature of 140℃, a pressure of 50 bars and flow rate of 1 mL.min-1 for extraction experiments conducted in the dynamic mode. Both PHWE and conventional methods achieved comparable extraction yields. Reflux and ultrasonic extractions had procedures that were slower (over 6 h) and employed large quantities (200 mL) of organic solvents. The PHWE method was simple and relatively fast as extraction was achieved in 15 min. At 95% confidence level (n = 3), reflux and ultrasonic methods recorded extraction yields that were not significantly different from that of PHWE. Moreover, PHWE employed a more readily available “green” solvent, (water) to achieve comparable results to those of conventional methods which utilized organic solvents. The percentage relative standard deviations (%RSD) for the extraction yields were less than 3% in all cases indicating the high reproducibility of the method. However, when using PHWE to extract thermally labile analytes like alkaloids, degradation effects also occurred. Increasing the temperatures certainly achieved higher extraction yields but also led to degradation of these thermally labile compounds indicating a necessity for optimization.展开更多
A technique of ultrasound-assisted low density solvent based dispersive liquid-liquid microextraction was developed for the determination of four phthalate esters, including dimethyl phthalate（DMP）, diethyl phthalat...A technique of ultrasound-assisted low density solvent based dispersive liquid-liquid microextraction was developed for the determination of four phthalate esters, including dimethyl phthalate（DMP）, diethyl phthalate（DEP）, di-n-butyl phthalate（DnBP） and di（2-ethylhexyl） phthalate（DEHP） in bottled water samples. A low density solvent, toluene, was selected as extraction solvent. In the extraction process, a mixture of 15 μL of toluene（extraction solvent） and 100 μL of methanol（disperser solvent） was rapidly injected into 1.0 mL of water samples. A cloudy solution was formed after ultrasounded for 5 min, and then centrifuged at 5000 r/min for 5 min. The enriched analytes in the floa- ting phase were determined by means of gas chromatograph. Under the optimum conditions, the enrichment factors were found to be in a range of 29--67, and the recoveries were ranged from 81.2% to 103.9%. The limits of the detection were in a range of 3.8--5.6 μg/L. The proposed method was applied to the extraction and determination of phthalate esters in bottled water samples, and the concentrations of phthalate esters found in the water samples were below the allowable levels.展开更多
为探究亚临界流体萃取天然产物的研究热点和趋势,对web of science核心合集中科学引文索引(Science Citation Index Expanded, SCIE)数据库内收录的相关文献进行了检索和筛选,并对筛选出的文献进行分析和综述。结果表明:有53个国家266...为探究亚临界流体萃取天然产物的研究热点和趋势,对web of science核心合集中科学引文索引(Science Citation Index Expanded, SCIE)数据库内收录的相关文献进行了检索和筛选,并对筛选出的文献进行分析和综述。结果表明:有53个国家266家机构发表相关文献282篇,以中国发文数量最多;研究机构主要以高等院校和研究所为主;亚临界流体萃取以亚临界水、丙烷、丁烷等溶剂为主;亚临界水萃取产物除了精油、多酚、黄酮等外,还延伸至植物蛋白、可溶性膳食纤维等功能性产物;亚临界丙烷、丁烷萃取的研究聚焦在开发新的特种植物种子油、油脂中保健成分及油粕中优质蛋白等物质的再利用。展开更多
文摘A quick, efficient and environmentally beneficial approach for the extraction of alkaloids in goldenseal based on pressurized hot water extraction (PHWE) is presented. PHWE was evaluated following the extraction of hydrastine and berberine which are the two main alkaloids of goldenseal. The effects of temperature and other parameters on extraction yields were monitored by high performance liquid chromatography coupled to diode array detector (HPLC-DAD). The extraction yields were compared to those achieved through reflux and ultrasonic extraction methods. PHWE employed hot water at an optimal temperature of 140℃, a pressure of 50 bars and flow rate of 1 mL.min-1 for extraction experiments conducted in the dynamic mode. Both PHWE and conventional methods achieved comparable extraction yields. Reflux and ultrasonic extractions had procedures that were slower (over 6 h) and employed large quantities (200 mL) of organic solvents. The PHWE method was simple and relatively fast as extraction was achieved in 15 min. At 95% confidence level (n = 3), reflux and ultrasonic methods recorded extraction yields that were not significantly different from that of PHWE. Moreover, PHWE employed a more readily available “green” solvent, (water) to achieve comparable results to those of conventional methods which utilized organic solvents. The percentage relative standard deviations (%RSD) for the extraction yields were less than 3% in all cases indicating the high reproducibility of the method. However, when using PHWE to extract thermally labile analytes like alkaloids, degradation effects also occurred. Increasing the temperatures certainly achieved higher extraction yields but also led to degradation of these thermally labile compounds indicating a necessity for optimization.
文摘A technique of ultrasound-assisted low density solvent based dispersive liquid-liquid microextraction was developed for the determination of four phthalate esters, including dimethyl phthalate（DMP）, diethyl phthalate（DEP）, di-n-butyl phthalate（DnBP） and di（2-ethylhexyl） phthalate（DEHP） in bottled water samples. A low density solvent, toluene, was selected as extraction solvent. In the extraction process, a mixture of 15 μL of toluene（extraction solvent） and 100 μL of methanol（disperser solvent） was rapidly injected into 1.0 mL of water samples. A cloudy solution was formed after ultrasounded for 5 min, and then centrifuged at 5000 r/min for 5 min. The enriched analytes in the floa- ting phase were determined by means of gas chromatograph. Under the optimum conditions, the enrichment factors were found to be in a range of 29--67, and the recoveries were ranged from 81.2% to 103.9%. The limits of the detection were in a range of 3.8--5.6 μg/L. The proposed method was applied to the extraction and determination of phthalate esters in bottled water samples, and the concentrations of phthalate esters found in the water samples were below the allowable levels.
文摘为探究亚临界流体萃取天然产物的研究热点和趋势,对web of science核心合集中科学引文索引(Science Citation Index Expanded, SCIE)数据库内收录的相关文献进行了检索和筛选,并对筛选出的文献进行分析和综述。结果表明:有53个国家266家机构发表相关文献282篇,以中国发文数量最多;研究机构主要以高等院校和研究所为主;亚临界流体萃取以亚临界水、丙烷、丁烷等溶剂为主;亚临界水萃取产物除了精油、多酚、黄酮等外,还延伸至植物蛋白、可溶性膳食纤维等功能性产物;亚临界丙烷、丁烷萃取的研究聚焦在开发新的特种植物种子油、油脂中保健成分及油粕中优质蛋白等物质的再利用。
