首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 106 毫秒
1.
墨红花超临界二氧化碳香味萃取成分的色谱-质谱法测定   总被引:1,自引:1,他引:1  
张骊  向智敏  毕丽君  谢珍珍  陈力 《色谱》1996,14(6):438-440
 由墨红花提取的精油或油树脂是优质的天然香料,被广泛用于化妆品和食品工业。超临界CO2萃取墨红花精油,既可保持很好的香气,又能克服传统的有机溶剂萃取时有残余溶剂的缺点。用气相色谱-质谱联用法对超临界CO2萃取物与石油醚萃取物中的组成进行了分析比较。色谱条件为:OV-101固定相,氦气,0.2mm×50m石英毛细管柱,柱温70℃2min,然后以5℃/min程序升温至250℃。超临界萃取条件为50℃,21MPa,CO2流量为10mL。  相似文献   

2.
墨红花超临界二氧化碳香味萃取成分的色谱-质谱法测定   总被引:2,自引:0,他引:2  
由墨红花提取的精油或油树脂是优质的天然香料,被广泛用于化妆品和食品工业。超临界CO2萃取墨红花精油,既可保持很好的香气,又能克服传统的有机溶剂萃取时有残余溶剂的缺点。用气相色谱-质谱联用法对超临界CO2萃取物与石油醚萃取物中的组成进行了分析比较。色谱条件为:OV-101固定相,氦气,0.2mm×50m石英毛细管柱,柱温70℃2min,然后以5℃/min程序升温至250℃。超临界萃取条件为50℃,21MPa,CO2流量为10mL。发现超临界萃取物中的成分包括了石油醚萃取物中的多数主要香味成分,但对香味影响较小的、分子量较大的烷烃和烯烃的含量较少。超临界二氧化碳萃取物的香气与鲜花相近。  相似文献   

3.
任丽  王国俊 《色谱》1998,16(3):238-243
 利用吸附剂GDX-301对黄河水中的有机污染物富集并以超临界CO2脱附后,通过气相色谱、色谱-红外-质谱联用技术对各目标分析物逐一定性,并比较了超临界CO2萃取和溶剂洗脱的结果。实验表明,在20MPa,60℃,40min条件下进行超临界CO2萃取时的萃取效率和溶剂萃取效率相当或略高。  相似文献   

4.
本文用超临界CO_2对高酸价麦胚油进行选择住萃取,结果表明,萃取温度和压力不同时,萃取物中甾醇的含量不同.且甾醇混合物主要为β-谷甾醇和菜籽甾醇。萃取物的酸价也明显高于高酸价麦胚油。  相似文献   

5.
八角的超临界CO2流体萃取产物化学成分的研究   总被引:15,自引:0,他引:15  
采用GC和GC-MS技术对八角的超临界CO2流体萃取物的化学成分进行了研究,共鉴定出34种化合物,它们的含量占出峰物质总量的962%。同时与八角的水蒸汽蒸馏产物的组成进行了比较。  相似文献   

6.
游静  包永新 《分析化学》1998,26(7):886-890
通过固体吸附富集,再用超临界CO2脱附后用气相色谱及质谱技术对实验室内空气中气相有机污染物进行了考察,文中对采样和萃取条件进行了优化,并与热脱附所得结果做了比较,结果表明在22MPa,80℃时,用甲醇改性的超临界CO2进行萃取的结果优于热脱附法,该法鉴定出气相有机污染物中52个组分,占色谱峰总面积的99.6%。  相似文献   

7.
通过团体吸附剂富集,再用超临界CO2脱附后用气相色谱及质谱技术对实验室内空气中气相有机污染物进行了考察。文中对采样和萃取条件进行了优化,并与热脱附所得结果做了比较。结果表明在22MPa,80℃时,用甲醇改性的超临界CO2进行萃取的结果优于热脱附法。该法鉴定出气相有机污染物中52个组分,占色谱峰总面积的99.6%。  相似文献   

8.
硫化态NiMoK/Al2O3变换催化剂对水的吸附性能   总被引:2,自引:0,他引:2  
硫化态NiMoK/Al_2O_3变换催化剂对水的吸附性能李利民,郭益群,王贵昌,王文祥(郑州大学化学系郑州450052)关键词水煤气变换催化剂,硫化,水吸附,脉冲气相色谱CO(Ni)MoK/Al_2O_3型催化剂用于变换反应时需首先进行硫化,硫化温度...  相似文献   

9.
新型碳分子筛毛细管色谱柱中国科学院兰州化学物理研究所色谱技术研究开发中心研究人员经过两年多的探索,成功地研制开发出碳分子筛石英毛细管气相色谱柱。经修饰改性的碳分子筛C-2000色谱柱能够一次进行分离H2、C2、N2、CO、CH4、CO2、C2H2、C...  相似文献   

10.
双柱串联色谱一次分析甲烷部分氧化制合成气产物   总被引:6,自引:0,他引:6  
采用PorapakN色谱柱,延迟空管和13X分子筛色谱柱串联方法,用一个TCD,通过AnaStar色谱工作站实时采集信号进行在线分析,可成功地一次性和分析POM产品气听CH4,CO,CO2,O2等几处可能组分,消除了两台色谱仪无法同时取样分析和在两个不同TCD检测器上采集数据引起的实验误差,提高了分析的可靠性。  相似文献   

11.
Colon cancer is one of the major causes of cancer mortality worldwide. Hydroalcoholic extract of ginger peel extract was more potent against colon cancer cells than ginger pulp hydroalcoholic extract using MTT assay, while ginger pulp hydroalcoholic extract showed higher anti-inflammatory and antioxidant activities. The two samples of ginger showed a different polyphenolic content and lipophilic composition. Peel extract possessed twice the polyphenolic content than pulp and the highest number of non-polar compounds. Among them, α-zingibirene was found to be the major constituent. The findings add to epidemiologic evidence for therapeutic effects of ginger peel in colorectal carcinoma.  相似文献   

12.
The rhizome of ginger (Zingiber officinale Roscoe) is known to have several bioactive compounds including gingerols and shogaols which possess beneficial health properties such as anti-inflammatory and chemopreventive effects. Based on recent observations that 6-shogaol may have more potent bioactivity than 6-gingerol, we obtained a 6-shogaol-rich extract from ginger and examined its effects on the nuclear factor E2-related factor2 (Nrf2)/antioxidant response element (ARE) pathway in vitro and in vivo. 6-Shogaol-rich extract was produced by extracting ginger powder with 95% ethanol at 80 °C after drying at 80 °C (GEE8080). GEE8080 contained over 6-fold more 6-shogaol compared to the room temperature extract (GEE80RT). In HepG2 cells, GEE8080 displayed much stronger inductions of ARE-reporter gene activity and Nrf2 expression than GEE80RT. GEE8080 stimulated phosphorylations of mitogen-activated protein kinases (MAPKs) such as ERK, JNK, and p38. Moreover, the GEE8080-induced expressions of Nrf2 and HO-1 were attenuated by treatments of SB202190 (a p38 specific inhibitor) and LY294002 (an Akt specific inhibitor). In a mouse model, the GEE8080 decreased the diethylnitrosamine (DEN)-mediated elevations of serum aspartate transaminase and alanine transaminase as well as the DEN-induced hepatic lipid peroxidation. Inductions of Nrf2 and HO-1 by GEE8080 were also confirmed in the mice. In addition, the administration of GEE8080 to the mice also restored the DEN-reduced activity and protein expression of hepatic antioxidant enzymes such as superoxide dismutase, glutathione peroxidase and catalase. In conclusion, GEE8080, a 6-shogaol-rich ginger extract, may enhance antioxidant defense mechanism through the induction of Nrf2 and HO-1 regulated by p38 MAPK and PI3k/Akt pathway in vitro and in vivo.  相似文献   

13.
The utilization of fossil fuels causes serious negative impacts on the environment and human life. To mitigate greenhouse gases and other pollutants, a novel combustion process-the nonflame combustion technology with a thermal cyclic carrier of molten salt is introduced. In this technology, a whole combustion is divided into two steps, i.e. , the section of producing oxide and the section of combustion. In the first step, oxygen is separated from air, and pure N2 is simultaneously formed which is easily recovered. In the other step, the fuels react with lattice oxygen in the oxides formed in the first step, and at the same time, thermal energy, CO2 and H2O vapor are produced. It is noted that the CO2 is easily separated from water vapor and ultimately captured. Theoretically, there are no environmental-unfriendly gases such as CO2, NOx and SO2 discharged in the whole combustion process. Some metal oxides scattered into molten salts play the roles of oxygen carriers in the combustion system, and they can constantly charge and discharge oxygen element from air to fuels during the combustion process. A nonflame combustion system with Li2CO3 K2CO3 Na2SO4 as the molten salt system, CH4 as the fuel and CuO as the catalyst was experimentally investigated. The experimental resuits show that the combustion process proceeded as it was theoretically analyzed, and CO2 with a high volume fraction of 77.0M--95.0M and N2 with a high volume fraction of 91.9%-99.3% were obtained. The high concentration of CO2 is favorable for capturing and storing subsequently. Therefore, the potential of reducing CO2 emissions of this nonflame combustion technology is huge.  相似文献   

14.
弋瑛  俞贤达 《应用化学》1993,10(1):77-79
前曾报道聚乙烯醇(PVA)与脂肪醛缩合后亲水性的羟基减少,影响到其薄膜的透湿性和透气性,本文考察PVA及其三种脂肪族缩醛物膜在加湿条件下的透气性。 PVA膜为10%PVA水溶液用流涎法制成。缩醛膜为PVA缩醛衍生  相似文献   

15.
The extraction of metallic nanoparticles from perovskite-type oxides(ABO3) under mild reducing conditions is a novel way to prepare well-dispersed supported catalysts(B/AOd). Herein, we found that the encapsulated PdO in perovskite LaCoO_3(PdO@LaCoO_3) could facilitate the phase transformation of the perovskite structure at a low temperature owing to both strong H2 spillover of Pd and intimate interaction between the encapsulated PdO and LaCoO3. The pure LaCoO3 without PdO was relatively inert to CO2 hydrogenation(CO2 conversion <4%). In contrast, PdO@LaCoO3 exhibited excellent CO2 methanation performance with 62.3% CO2 conversion and >99% CH4 selectivity. The characterization results demonstrated that the catalytically active Co2 C was in-situ formed by carburization of the extracted Co0 during CO2 methanation for the PdO@LaCoO3 sample. Whereas, the LaCoO3 with surface supported PdO(PdO/LaCoO3) showed a weak interaction and remained a perovskite structure with few Co2C active centers after the catalytic reaction, which was similar to the parent LaCoO3. Accordingly, the PdO/LaCoO3 showed an inferior catalytic performance with 31.8% CO2 conversion and 87.4% CH4 selectivity. Therefore, the designed encapsulation structure of PdO within perovskite is critical to extract metallic NPs from perovskite-type oxides, which has the potential to prepare other integrated nanocatalysts based on perovskite-type oxides.  相似文献   

16.
山楂挥发性化合物的气相色谱-质谱分析   总被引:4,自引:0,他引:4  
陈凌云  谢笔钧  游铜锡 《色谱》1997,15(3):219-221
 采用蒸馏-萃取法收集山楂果的挥发性化合物,通过气相色谱及气相色谱/质谱分析,鉴定了32种化合物,占总峰面积的61%~68%。其中主要的10种化合物是顺-3-己烯醇、顺-3-乙酸己烯酯、α-萜品醇、糠醛、己醇、乙酸己酯、壬醛、柠檬醛、3-戊烯-2-酮,反-2-癸烯醛等。  相似文献   

17.
在丙烯氨氧化合成丙烯腈过程中,尾气内含有因反应而生成的CO2,CO,C2H4,未反应完全的C3H6,O2和不参与反应的N2以及丙烯原料气中少量的C3H8。使用含有双阀、双检测器、双色谱柱的气相色谱系统可使上述所有气体得到分离,而且分离效果好,定量准确,操作简单,实用性强  相似文献   

18.
几种聚醚酰亚胺的气体透过性能   总被引:6,自引:0,他引:6  
本文研究了一系列芳环聚醚酰亚胺(PEI)对H_2、CO_2、O_2和N_2的透过性能与分子结构之间的关系。单醚酐型聚醚酰亚胺具有较高的透氢系数和H_2/N_2分离系数。由半刚性的4,4′-二氨基二苯酮(DABP)与柔性的三苯二醚四酸二酐(HQDPA)、二苯醚四酸二酐(ODPA)缩聚得到的聚醚酰亚胺具有很高的H_2/N_2、CO_2/N_2和O_2/N_2分离系数。  相似文献   

19.
采用离子色谱法测定杂多酸中痕量阴离子。由于常规的淋洗液(如Na2CO3,NaOH)呈碱性,使杂多酸迅速分解生成磷酸根,致使测定结果偏高。实验通过在常规淋洗液中加入适量两性离子后,调节淋洗液的pH为中性,从而能准确测定杂多酸中磷酸根氯离子和硫酸根的含量值。经过比较分别用去离子水和流动相稀释的样品中磷酸根的测定结果,确定淋洗液的最佳条件为2.5mmol/LNa2CO3-9.0mmol/LCHES,在该条件下测定,快速、准确、灵敏,且有较好的灵敏度和重现性。  相似文献   

20.
Abstract

For the analysis of metsulfuron-methyl in the crop soils with a sensitivity limit of 0.3 μg kg?1 dry soil, in the soil extract metsulfuron-methyl was separated from its soil metabolites and the soil impurities by repeated thin-layer chromatographies (TLC). In the cleaned soil extract, diazomethane transformed metsulfuron-methyl 1 into N,N′ -dimethyl metsulfuron-methyl 2 (methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)methylamino]carbonyl]methylamino]sulfonyl]benzoate). In the gas-liquid chromatograph with detection by electron capture (GC-EC) and in the combined gas chromatograph-mass spectrometer (GC-MS), 2 was transformed into 1-dioxy-2-N-methyl-3-keto-1,2-benzisothiazole 3 which was measured by GC-EC with confirmation by GC-MS. The metsulfuron-methyl soil metabolites 2-sulfonamido-methylbenzoate 6, 1-dioxy-3-keto-1,2-benzisothiazole (saccharin) 7 and 2-sulfonamidobenzoic acid 8 were analyzed in the soil of winter wheat crops by a procedure similar to the one for metsulfuron-methyl. After their separation and purification in the soil extracts by TLC, 7 and 8 were methylated, and analyzed as 3 in the GC-EC and GC-MS apparatus where the generated 6 was quantitatively transformed into 3; 6 was analyzed as such with the GC and GC-MS apparatus wherein it was transformed into 3. The sensitivity limit for each metabolite was 0.3 μg of equivalents of metsulfuron-methyl kg?1dry soil. The syntheses of the analysis standards of the metsulfuron-methyl derivatives 2 and 3, and of the metsulfuron-methyl metabolites 6, 7 and 8 are described. The transformation pathways of metsulfuron-methyl and of its derivatives are different from those of the pyridine-pyrimidine sulfonylurea herbicides flupyrsulfuron-methyl and rimsulfuron. The soil analysis of a sulfonylurea -by means of one of its transformation product- needs a previous study of the chemical reactivity of the sulfonylurea. This leads to the analysis procedures for the main soil metabolites of the sulfonylurea.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号