In this paper a simple preparative method for isolation and purification of ginkgolides A and B was developed,As starting material,a commercially available standardized ginkgo extract (EGb761,containing 24% flavonoid ...In this paper a simple preparative method for isolation and purification of ginkgolides A and B was developed,As starting material,a commercially available standardized ginkgo extract (EGb761,containing 24% flavonoid and 6% terpene trilactones) was used,After a pretreatment step,optimized by the uniform design method ,the concentrated intermediate extract with high content of GA and gb(+90%) was separated into the individual terpenes by preparative liquid chromatography eluted with petroleum ether-ethylacetate,Analysis of products was carried out by means of HPLC-ELSD(evaporative light -scattering detector),The results show that ginkgolides A and B are obtained in higher yield and better purity.展开更多
Crude oil hydrocarbon composition characteristics and oil viscosity prediction are important bases in petroleum exploration. A total of 54 oil/heavy-oil samples and 17 oil sands were analyzed and quantified using both...Crude oil hydrocarbon composition characteristics and oil viscosity prediction are important bases in petroleum exploration. A total of 54 oil/heavy-oil samples and 17 oil sands were analyzed and quantified using both comprehensive 2D gas chromatog raphy (GCxGC) and comprehensive 2D gas chromatography/time-of-flight mass spectrometry (GCxGC/TOFMS). The results show that crude oil in the West slope is mainly heavy oil and its hydrocarbon composition is characterized overall by paraf fins 〉 mono-aromatics 〉 naphthenes 〉 non-hydrocarbons 〉 di-aromatics 〉 tri-aromatics 〉 tetra-aromatics. Aromatics are most abundant and non-hydrocarbons are least abundant, whilst content differences among paraffins, naphthenes, aromatics, and non-hydrocarbons are less than 15%. There are two types of heavy oil, secondary type and mixing type. Biodegradation is the main formation mechanism of heavy oil. Biodegradation levels cover light biodegradation, moderate biodegradation, and se- vere biodegradation. With increasing biodegradation, paraffin content decreases while contents of aromatics and non- hydrocarbons increase. In contrast, naphthene content increases first and then decreases with increasing biodegradation. In se- vere biodegradation stage, naphthenes decrease more quickly than aromatics and non-hydrocarbons. This provides a new method for studying oil/heavy-oil biodegradation mechanism and biodegradation resistance of different hydrocarbons at dif- ferent biodegradation stages. In the Longhupao-Daan terrace and Qijia-Gulong depression, most crude oil is conventional oil. Its composition is dominated by paraffins with the lowest content of aromatics. In some casual oil wells from the Long- hupao-Daan terrace, crude oil from Saertu oil reservoirs is moderately biodegraded whereas crude oil from Putaohua oil reser voir is lightly biodegraded. Chemical parameters using saturate hydrocarbons and aromatics are usually not suitable for deter mining organic type and thermal maturity of biodegraded oil, especially of moderately or severely biodegraded oil, whilst Ts/(Ts+Tm) ratio can be used to determine thermal maturity of both conventional crude oil and heavy oil.展开更多
A method was established to determine the activity of hexokinase by reverse-phase high-performance liquid chromatography (RP-HPLC). The activity of hexokinase was determined by detecting the amount of ADP in the rea...A method was established to determine the activity of hexokinase by reverse-phase high-performance liquid chromatography (RP-HPLC). The activity of hexokinase was determined by detecting the amount of ADP in the reaction that converts glucose into glucose-6-phosphate. The separation degree of ATP and ADP was as good as 3.46 (separation degree^l.5). In the range of 0.01-0.40 mmol/L, there was a good linear relationship between concentration of ADP and its peak areas (the correlation coefficient was 0.999). The relative standard deviation(RSD) of intraday was 1.43%-1.46%, that of interday was 2.12%-2.15%. At 30℃ (optimal temperature) and pH7.0 (optimal pH), the recovery rate of hexokinase was 95.3%-97.6%. The results showed that the method had good precision and high recovery rate, and the enzyme activity was determined through only one-step reaction. To some extent, this method can reduce the cost.展开更多
基金Supported by the Natural Science Foundation of Tianjin(No.993606911).
文摘In this paper a simple preparative method for isolation and purification of ginkgolides A and B was developed,As starting material,a commercially available standardized ginkgo extract (EGb761,containing 24% flavonoid and 6% terpene trilactones) was used,After a pretreatment step,optimized by the uniform design method ,the concentrated intermediate extract with high content of GA and gb(+90%) was separated into the individual terpenes by preparative liquid chromatography eluted with petroleum ether-ethylacetate,Analysis of products was carried out by means of HPLC-ELSD(evaporative light -scattering detector),The results show that ginkgolides A and B are obtained in higher yield and better purity.
基金supported by National Basic Research Program of China(Grant No.2006CB701404)CNPC Grand S&T Special Project(Grant No.2012E-2603)
文摘Crude oil hydrocarbon composition characteristics and oil viscosity prediction are important bases in petroleum exploration. A total of 54 oil/heavy-oil samples and 17 oil sands were analyzed and quantified using both comprehensive 2D gas chromatog raphy (GCxGC) and comprehensive 2D gas chromatography/time-of-flight mass spectrometry (GCxGC/TOFMS). The results show that crude oil in the West slope is mainly heavy oil and its hydrocarbon composition is characterized overall by paraf fins 〉 mono-aromatics 〉 naphthenes 〉 non-hydrocarbons 〉 di-aromatics 〉 tri-aromatics 〉 tetra-aromatics. Aromatics are most abundant and non-hydrocarbons are least abundant, whilst content differences among paraffins, naphthenes, aromatics, and non-hydrocarbons are less than 15%. There are two types of heavy oil, secondary type and mixing type. Biodegradation is the main formation mechanism of heavy oil. Biodegradation levels cover light biodegradation, moderate biodegradation, and se- vere biodegradation. With increasing biodegradation, paraffin content decreases while contents of aromatics and non- hydrocarbons increase. In contrast, naphthene content increases first and then decreases with increasing biodegradation. In se- vere biodegradation stage, naphthenes decrease more quickly than aromatics and non-hydrocarbons. This provides a new method for studying oil/heavy-oil biodegradation mechanism and biodegradation resistance of different hydrocarbons at dif- ferent biodegradation stages. In the Longhupao-Daan terrace and Qijia-Gulong depression, most crude oil is conventional oil. Its composition is dominated by paraffins with the lowest content of aromatics. In some casual oil wells from the Long- hupao-Daan terrace, crude oil from Saertu oil reservoirs is moderately biodegraded whereas crude oil from Putaohua oil reser voir is lightly biodegraded. Chemical parameters using saturate hydrocarbons and aromatics are usually not suitable for deter mining organic type and thermal maturity of biodegraded oil, especially of moderately or severely biodegraded oil, whilst Ts/(Ts+Tm) ratio can be used to determine thermal maturity of both conventional crude oil and heavy oil.
基金Supported by the Key Project of Science and Technology Department of Fujian Province (2008Y0052)
文摘A method was established to determine the activity of hexokinase by reverse-phase high-performance liquid chromatography (RP-HPLC). The activity of hexokinase was determined by detecting the amount of ADP in the reaction that converts glucose into glucose-6-phosphate. The separation degree of ATP and ADP was as good as 3.46 (separation degree^l.5). In the range of 0.01-0.40 mmol/L, there was a good linear relationship between concentration of ADP and its peak areas (the correlation coefficient was 0.999). The relative standard deviation(RSD) of intraday was 1.43%-1.46%, that of interday was 2.12%-2.15%. At 30℃ (optimal temperature) and pH7.0 (optimal pH), the recovery rate of hexokinase was 95.3%-97.6%. The results showed that the method had good precision and high recovery rate, and the enzyme activity was determined through only one-step reaction. To some extent, this method can reduce the cost.