An ultra-performance liquid chromatography quadrupole time of flight mass spectrometry （UPLC-qTOF-MS/MS） method was developed and validated for the simultaneous determination of glycyrrhizin and glycyrrhetic acid. T...An ultra-performance liquid chromatography quadrupole time of flight mass spectrometry （UPLC-qTOF-MS/MS） method was developed and validated for the simultaneous determination of glycyrrhizin and glycyrrhetic acid. These analytes were separated on a reverse phase C18 column using a mobile phase of acetonitrile：2% acetic acid in water （75：25, v/v） with a flow rate of 200 μL/min. The qTOF-MS was operated under multiple reaction monitoring （MRM） mode using the electrospray ionization （ESI） technique with positive ion polarity. A comparison of three different extraction techniques i.e. accelerated solvent extraction （ASE）, extraction under ultrasonic waves （USW） and the classical extraction by percolation （CE） method was done and quantification of these extracts was also carried out by the proposed method.展开更多
A coupled reaction-solvent extraction process was used to remove HC1 from a simulated distiller waste. The extraction performances of various extractants and diluents were compared and the apparent basicity ofN235 （a...A coupled reaction-solvent extraction process was used to remove HC1 from a simulated distiller waste. The extraction performances of various extractants and diluents were compared and the apparent basicity ofN235 （a mixture of tertiary amines） in various diluents was determined. The best results were obtained using N235 and isoamyl alcohol as the extractant and diluent, respectively. The yield of HC1 from the coupled extraction was 75% with this extraction system. The mechanisms for the removal of HC1 in both the direct and coupled extractions were investigated. For the coupled extraction, the formation of an RaNHC1 ion-pair complex was involved in the HC1 removal. For the direct extraction, the mechanism involved the formation of hydrogen bonds at high concentrations of HC1.展开更多
Recently, biodiesel has received much more attention. Soybean oil, rapeseed oil, palm oil and corn oil are primary feedstock for biodiesel production. However, biodiesel production from these traditional oil-rich crop...Recently, biodiesel has received much more attention. Soybean oil, rapeseed oil, palm oil and corn oil are primary feedstock for biodiesel production. However, biodiesel production from these traditional oil-rich crops is limited by land availability, climate, and environmental and social issues regarding the use of feed and food crops for fuel. Oleaginous microorganisms, including microalgae, bacteria, yeast and fungi can be cultivated with high lipid contents and used as promising feedstock for biodiesel production. However, the high cost of biodiesel production using oil microorganisms has been the biggest obstacle for its industrialization. The process of biodiesel production from microorganisms involves many steps, of which the lipids extraction is the most important and costly. Therefore, searching for an effective and economical extraction system is critical. Various approaches of lipids extraction are discussed in this review, including traditional extraction procedures such as solvent extraction, pressing and solvent integrated extraction, as well as some new procedures.展开更多
文摘An ultra-performance liquid chromatography quadrupole time of flight mass spectrometry （UPLC-qTOF-MS/MS） method was developed and validated for the simultaneous determination of glycyrrhizin and glycyrrhetic acid. These analytes were separated on a reverse phase C18 column using a mobile phase of acetonitrile：2% acetic acid in water （75：25, v/v） with a flow rate of 200 μL/min. The qTOF-MS was operated under multiple reaction monitoring （MRM） mode using the electrospray ionization （ESI） technique with positive ion polarity. A comparison of three different extraction techniques i.e. accelerated solvent extraction （ASE）, extraction under ultrasonic waves （USW） and the classical extraction by percolation （CE） method was done and quantification of these extracts was also carried out by the proposed method.
文摘A coupled reaction-solvent extraction process was used to remove HC1 from a simulated distiller waste. The extraction performances of various extractants and diluents were compared and the apparent basicity ofN235 （a mixture of tertiary amines） in various diluents was determined. The best results were obtained using N235 and isoamyl alcohol as the extractant and diluent, respectively. The yield of HC1 from the coupled extraction was 75% with this extraction system. The mechanisms for the removal of HC1 in both the direct and coupled extractions were investigated. For the coupled extraction, the formation of an RaNHC1 ion-pair complex was involved in the HC1 removal. For the direct extraction, the mechanism involved the formation of hydrogen bonds at high concentrations of HC1.
基金Acknowledgements This work was financed by the National Natural Science Foundation of China （Grant No. 20976140）. The authors are grateful to Department of Chemical Engineering, School of Engineering, University of Louisiana at Lafayette, USA and Key Laboratory for Green Chemical Process of Ministry of Education for providing the condition of researching.
文摘Recently, biodiesel has received much more attention. Soybean oil, rapeseed oil, palm oil and corn oil are primary feedstock for biodiesel production. However, biodiesel production from these traditional oil-rich crops is limited by land availability, climate, and environmental and social issues regarding the use of feed and food crops for fuel. Oleaginous microorganisms, including microalgae, bacteria, yeast and fungi can be cultivated with high lipid contents and used as promising feedstock for biodiesel production. However, the high cost of biodiesel production using oil microorganisms has been the biggest obstacle for its industrialization. The process of biodiesel production from microorganisms involves many steps, of which the lipids extraction is the most important and costly. Therefore, searching for an effective and economical extraction system is critical. Various approaches of lipids extraction are discussed in this review, including traditional extraction procedures such as solvent extraction, pressing and solvent integrated extraction, as well as some new procedures.
