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甾醇、甾烷醇柱前衍生高效液相荧光分析 总被引:1,自引:0,他引:1
采用荧光衍生化试剂2-(9-咔唑)乙酰氯,对天然产物谷甾醇、豆甾醇、菜油甾醇及谷甾烷醇的柱前衍生化条件,包括催化剂的种类、反应温度、衍生化时间等进行了考察,结果表明催化剂选用三乙胺,反应温度80℃,时间20 min,衍生产物具有恒定的最大检测响应值.利用高效液相色谱对衍生产物进行分析,并对衍生物的分离进行了优化选择,达到了较好的基线分离,检出限为12.6~29.5 nmol/L.方法应用于血清样品的测定,谷甾醇、豆甾醇、菜油甾醇和谷甾烷醇的标准加入回收率分别为101.9%、102.4%、101.0%和103.2%. 相似文献
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筛选出适合分离大豆甾醇的最佳反相色谱柱W aters symm etry C18(4.6mm×250mm)和流动相(乙腈-异丙醇,95∶5,V/V),考察了流动相配比和柱温对大豆甾醇分离的影响。从大豆甾醇产品中基线分离出豆甾醇、β-谷甾醇和菜油甾醇及菜籽甾醇这4种主要甾醇,还通过对分离出的其它多个未知峰馏分收集制备后作GC/MS分析,鉴定为γ-谷甾醇、24-β-菜油甾醇、表菜籽甾醇和豆甾醇异构体。在优化的色谱条件下,利用HPLC测定了大豆油和脱臭馏出物及大豆甾醇产品的部分样品中各甾醇组分的含量,豆甾醇和β-谷甾醇的检出限为14.4 ng和10.6 ng,HPLC测定大豆油样品中这2种甾醇的平均回收率为97.3%和96.9%。 相似文献
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顶羽菊化学成分的研究 总被引:3,自引:0,他引:3
本文对顶羽菊植物化学成分进行了研究,从中分离出9种化合物,用红外、紫外、核磁共振和质谱分析以及化学反应鉴定了结构,它们是二十九碳烷(Ⅰ)、二十二烷醇(Ⅱ)、豆甾烷醇(Ⅲ)、β-谷甾醇(Ⅳ)、豆甾-7-烯-3-醇(Ⅴ)、三十四碳酸(Ⅵ)、2,4-二(邻甲基偶氮苯)-萘酚-1(Ⅶ)、β-谷甾醇-β-D-葡萄糖甙(Ⅷ)、洋芹素-5-β-D-葡萄糖甙(Ⅸ),其中化合物Ⅶ是首次从天然界获得。 相似文献
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We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992. 相似文献
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David W. Murhammer 《Applied biochemistry and biotechnology》1991,31(3):283-292
The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed. 相似文献
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Karadakov PB 《The journal of physical chemistry. A》2008,112(31):7303-7309
The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei. 相似文献
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Wenbi Guan 《International journal of environmental analytical chemistry》2013,93(6):679-691
A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg?1, the maximum residue level of European Union for quizalofop-p-ethyl). 相似文献
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The P-anilino-P-chalcogeno(imino)diazasilaphosphetidines [Me(2)Si(mu-N(t)Bu)(2)P=E(NHPh)] (E = O (3), S (4), Se (5), N-p-tolyl (6)) were synthesized by oxidizing the P-anilinodiazasilaphosphetidine [Me(2)Si(N(t)Bu)(2)P(NHPh)] (2) with cumene hydroperoxide, sulfur, selenium, and p-tolyl azide, respectively. The lithium salt of 4 reacted with thallium monochloride to produce ([Me(2)Si(mu-N(t)Bu)(2)P=S(NPh)-kappaN-kappaS]Tl)(7), which features a two-coordinate thallium atom. Treatment of 4-6 with AlMe(3) gave the monoligand dimethylaluminum complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE]AlMe(2)) (E = S (8), Se (9), N-p-tolyl (10)), respectively. In these complexes the aluminum atom is tetrahedrally coordinated by one chelating ligand and two methyl groups, as a single-crystal X-ray analysis of 8 showed. A 2 equiv amount of 4-6 reacted with diethylzinc to produce the homoleptic diligand complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE](2)Zn)(E = S (11), Se (12), N-p-tolyl (13)). A crystal-structure analysis of 11 revealed a linear tetraspirocycle with a tetrahedrally coordinated, central zinc atom. 相似文献
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多环芳二酐型聚酯亚胺膜的透气性能李悦生,丁孟贤,徐纪平(浙江大学高分子科学与工程研究所,杭州,310027)(中国科学院长春应用化学研究所)关键词聚醚酰亚胺,聚酯酰亚胺,膜,透气性通常的聚酰亚胺加工性能较差,在芳环二酐的苯环间引入醚键等柔性基团后,其... 相似文献