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 109 毫秒
1.
用超临界萃取技术对产于青藏高原上的狭果茶种子中脂肪酸进行萃取,其萃取率为12%。用毛细管气相色谱对萃取的脂肪酸进行了分离和分析。结果表明不饱和脂肪酸的质量分数在90%以上。其中α 亚麻酸(α Linolenicae ia)为27.4%,γ 亚麻酸(γ Linoleicaeia)为4.93%,亚油酸(Linoleicaeia)为32 61%。  相似文献   

2.
用超临界萃取技术对青藏高原藏药特有植物门源茶Biao果实中脂肪酸进行萃取,用毛细管气相色谱进行分离和分析,结果表明不饱和脂肪酸在90%以上,其中亚油酸为36.48%,r-亚麻酸为4.5%,α-亚麻酸为29.26%。  相似文献   

3.
建立了集萃取与净化于一体的加速溶剂/固液固萃取(AS/SLSE)卷烟烟气中痕量苯并[a]芘(BaP)的样品前处理方法。卷烟烟气经捕集后,用AS/SLSE提取和净化,萃取液浓缩后进行色谱分析。优化了AS/SLSE吸附剂、萃取温度、吹扫体积、静态萃取时间及循环次数等条件。在优化条件下(5 g硅镁型吸附剂、萃取温度100℃、吹扫体积40%、静态萃取时间3 min循环2次,样品连续萃取3次),AS/SLSE-气相色谱/质谱法(GC/MS)分析卷烟烟气中苯并[a]芘方法的检出限为1.0μg/L,回收率为97.1%,相对标准偏差(RSD)为2.5%。方法成功用于卷烟烟气样品的分析,测定结果与国家标准推荐方法吻合。  相似文献   

4.
王巧娥  宋萍  丁明玉 《色谱》2006,24(1):55-57
建立了反相高效液相色谱-蒸发光散射检测器(RP-HPLC-ELSD)测定紫苏子油中α-亚麻酸含量的方法。紫苏子油样用0.5 mol/L的KOH-CH3OH溶液于60 ℃水浴中皂化20 min、6 mol/L的盐酸酸化后用无水乙醚萃取,再用氮气流吹干乙醚,用甲醇溶解并定容,然后直接进行RP-HPLC-ELSD分析。结果表明,当α-亚麻酸质量为6.2~45.4 μg时,其峰面积A的对数(lg A)与α-亚麻酸质量m(μg)的对数(lg m)呈线性关系,线性方程为lg A=1.3675·lg m-1.628,相关系数为0.9973(n=5)。以信噪比S/N=3计算,方法的检出限为0.11 μg。被分析的紫苏子油中α-亚麻酸的含量为6.79%(质量分数),相对标准偏差(RSD)为5.1%(n=5);平均回收率为102%,RSD为6.3%(n=5)。该方法简单、快速、准确。  相似文献   

5.
利用超临界CO2萃取藏药波棱瓜种子油,并对种子油进行了气相色谱-质谱分析.实验确定的最佳超临界萃取的条件是:萃取温度45℃,萃取压力为20 MPa,CO2流量为35~40 kg/h,提取时间为120 min,在此条件下波棱瓜种子油的提取率为33.35%.利用气相色谱-质谱对种子油分析,结果发现其主要含有各类不饱和脂肪酸,其中亚麻酸、亚油酸、油酸的相对含量分别为:12.271%、20.149%和52.282%.通过对波棱瓜种子油的分析研究为其进一步开发利用提供了科学依据.  相似文献   

6.
分别采用丙酮、N,N-二甲基甲酰胺、乙醇胺、乙二胺对陕西某一地区煤进行了索氏萃取和搅拌萃取,其中以乙二胺为溶剂,采用简单搅拌萃取的萃取率最高,可达17.1%。建立了气相色谱/质谱法(GC/MS)测定乙二胺和乙醇胺萃取物的分析方法,结果表明:乙二胺萃取物中可检测出53种化合物,主要为芳香烃、脂肪烃、含氮及含氧化合物四类组分。含氮化合物的成分含量最高,气相色谱分析其面积归一化相对含量为75.64%。检测出的乙醇胺萃取物种类较少,与乙二胺萃取物的组成成分也有差别。并对影响萃取率和萃取物组成成分的因素进行了分析。  相似文献   

7.
建立了一种人体唾液中苯丙胺(AM)、甲基苯丙胺(MAM)、 3, 4-亚甲二氧基苯丙胺(MDA)、 3, 4-亚甲二氧基甲基苯丙胺(MDMA)毒品的超声波液液萃取-气相色谱/质谱-选择离子检测方法. 对萃取溶剂、萃取时间等参数进行了考查, 确定了乙酸乙酯为萃取溶剂, 在超声波下液液萃取2 min. 用该溶剂对添加毒品的唾液进行提取, 采用气相色谱/质谱-选择离子检测法(GC/MS-SIM)检测, 获得了良好线性, 相对标准偏差在15%内, 准确性均在80%~115%之间, 最小检测限可达0.05 μg/mL. 该方法未对毒品进行衍生化处理, 可用于缴获毒品及嫌疑吸毒者人体生物检材中苯丙胺类毒品的分析.  相似文献   

8.
微波萃取/气相色谱-质谱测定土壤中的多氯联苯   总被引:10,自引:1,他引:9  
分别对多氯联苯的微波萃取条件进行了优化。优化后的分析条件为微波功率1200 W,萃取温度115℃,萃取时间20 min,萃取溶剂为V(正己烷)∶V(丙酮)=1∶1。方法的检出限为20~30 ng/g,线性范围40~4000 ng/mL(多氯联苯总量),相关系数均大于0.9990,样品基体加标回收率为92.2%~115%,相对标准偏差为9.4%(n=6)。  相似文献   

9.
用超临界萃取技术对产于青藏高原上的狭果茶蔗种子中脂肪酸进行萃取,其萃取率为12%。用毛细管气相色谱对萃取的脂肪酸进行了分离和分析。结果表明不饱和脂肪酸的质量分数在90%以上。其中α-亚麻酸(α-Linolenic aeia)为27.4%,γ-亚麻酸(γ-Linoleic aeia)为4.93%,亚油酸(Unoleic aeia)为32.61%。  相似文献   

10.
本文建立了超声波辅助萃取/固相萃取法-气质联用法(UAE/SPE-GS/MS)同时测定纺织固废物中17种氯苯类污染物的分析方法。从超声萃取溶剂、超声萃取时间、超声萃取温度和固相萃取小柱等前处理条件进行优化,以保留时间定性,外标法定量。结果表明,纺织固废样品在超声50℃的水浴中经二氯甲烷溶剂超声萃取30min后,再通过弗罗里硅土(Florisil)固相萃取柱净化,测得17种氯苯类污染物的回收率为80%~107.6%,相对偏差RSD(n=10)小于5.5%。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

16.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

17.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

18.
The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.  相似文献   

19.
20.
设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。  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