The application of soxhlet, ultrasonic and accelerated solvent extractiontechniques to the analysis of six organochlorine pesticides (α-HCH, β-HCH, γ-HCH, o, p'-DDT,p,p'-DDT and p,p'-DDE) in Taihu Lake ...The application of soxhlet, ultrasonic and accelerated solvent extractiontechniques to the analysis of six organochlorine pesticides (α-HCH, β-HCH, γ-HCH, o, p'-DDT,p,p'-DDT and p,p'-DDE) in Taihu Lake sediment samples is described. It was found that the limits ofquantification ranged from 0.002 μg g^(-1) to 0.004 μg g^(-1), and the recoveries oforganochlorine pesticides with the three extraction techniques were acceptable ( 】80.7%). With amass selective detector, better results were obtained by accelerated solvent extraction usinghexane-acetone (1:1) as compared with soxhlet and ultrasonic extraction. It was shown that theaccelerated solvent extraction was the optimum technique for the analysis of organochlorinepesticides in sediments. The general features of the three extraction techniques are also presented.展开更多
The development of a rapid, robust and reliable method for extracting plant food materials is important for screening a wide range of plant bioactives for their health benefits. In this study, extractions of bioactive...The development of a rapid, robust and reliable method for extracting plant food materials is important for screening a wide range of plant bioactives for their health benefits. In this study, extractions of bioactive polyphenolic com-pounds from fruits and vegetables were per-formed using a pressurised solvent extraction technique. Variables including solvent, extrac-tion temperature and time, and number of ex-traction cycles, were optimised to develop a rapid and efficient extraction protocol. The re-sulting extracts were then analysed for antioxi-dant capacity, total phenolic content and com-position. The optimal parameters found were 19:1 methanol/water (95% methanol) as solvent and three extraction cycles, of 10 minutes at 40oC or 2 minutes at 100oC. High performance liquid chromatography mass spectrometry did not detect any difference in extract composition between low and high temperatures. Extraction at 100°C generally gave a moderately higher yield of polyphenolics for some fruit and vege-table extracts but appeared to reduce the anti-oxidant activity particularly for turnip leaf, el-derberry and sour cherry extracts as measured by oxygen radical absorbance capacity assay. We found that all 40°C extracts were better at protecting cells from H2O2-induced cellular damage than their 100°C counterparts. The 40°C apple puree and elderberry extracts were about 2 fold and 1.7 fold more effective, respectively, than extracts prepared at 100°C. Our results demonstrated that pressurised solvent extrac-tion technique with careful parameter selection can be used as a quick method for screening the health benefits of plant food materials.展开更多
考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水...考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水)=1∶1为溶媒,在125℃用加速溶剂萃取仪提取,所得提取物对DPPH自由基的清除率为89.378%,而索式提取法仅为68.45%。表明加速溶剂萃取技术可以作为萝芙木中活性成分的一种高效提取手段。展开更多
文摘The application of soxhlet, ultrasonic and accelerated solvent extractiontechniques to the analysis of six organochlorine pesticides (α-HCH, β-HCH, γ-HCH, o, p'-DDT,p,p'-DDT and p,p'-DDE) in Taihu Lake sediment samples is described. It was found that the limits ofquantification ranged from 0.002 μg g^(-1) to 0.004 μg g^(-1), and the recoveries oforganochlorine pesticides with the three extraction techniques were acceptable ( 】80.7%). With amass selective detector, better results were obtained by accelerated solvent extraction usinghexane-acetone (1:1) as compared with soxhlet and ultrasonic extraction. It was shown that theaccelerated solvent extraction was the optimum technique for the analysis of organochlorinepesticides in sediments. The general features of the three extraction techniques are also presented.
文摘The development of a rapid, robust and reliable method for extracting plant food materials is important for screening a wide range of plant bioactives for their health benefits. In this study, extractions of bioactive polyphenolic com-pounds from fruits and vegetables were per-formed using a pressurised solvent extraction technique. Variables including solvent, extrac-tion temperature and time, and number of ex-traction cycles, were optimised to develop a rapid and efficient extraction protocol. The re-sulting extracts were then analysed for antioxi-dant capacity, total phenolic content and com-position. The optimal parameters found were 19:1 methanol/water (95% methanol) as solvent and three extraction cycles, of 10 minutes at 40oC or 2 minutes at 100oC. High performance liquid chromatography mass spectrometry did not detect any difference in extract composition between low and high temperatures. Extraction at 100°C generally gave a moderately higher yield of polyphenolics for some fruit and vege-table extracts but appeared to reduce the anti-oxidant activity particularly for turnip leaf, el-derberry and sour cherry extracts as measured by oxygen radical absorbance capacity assay. We found that all 40°C extracts were better at protecting cells from H2O2-induced cellular damage than their 100°C counterparts. The 40°C apple puree and elderberry extracts were about 2 fold and 1.7 fold more effective, respectively, than extracts prepared at 100°C. Our results demonstrated that pressurised solvent extrac-tion technique with careful parameter selection can be used as a quick method for screening the health benefits of plant food materials.
文摘考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水)=1∶1为溶媒,在125℃用加速溶剂萃取仪提取,所得提取物对DPPH自由基的清除率为89.378%,而索式提取法仅为68.45%。表明加速溶剂萃取技术可以作为萝芙木中活性成分的一种高效提取手段。
