生物催化的Baeyer-Villiger氧化反应研究

Baeyer-Villiger氧化反应是一种很重要的化学反应，产生的许多中间体或产物可以被用来生产多种化学产品和药物。此反应具有多功能性，可以氧化多种羰基化合物，但是化学方法中的必需反应物——氧化剂在生产、储存、运输、反应的过程中都存在很多的不安全因素，反应的立体选择性也不强，而生物转化则具有底物选择性、立构选择性、化学选择性、对映选择性等一般化学反应中不具备的优点，在精细化工中占有很大的优势。在工业生物催化中有很好的应用前景。 为了研究生物催化的Baeyer-Villiger反应，我们从本实验室保藏菌种中分离筛选出一株能够以环己酮作为唯一碳源的菌株，进行初步研究并对其产物进行GC/MS定性，探讨了pH，装液量，底物浓度，培养时间，温度以及转速等条件对细菌生长的影响，并进一步研究了细菌的底物广谱性。 此菌株经鉴定属于邻单胞菌属Plesiomonas sp.)， 根据正交试验，确定了菌的最佳生长条件：底物浓度为1mL/L，底物浓度过高对菌株生长有抑制作用，转速为150 rpm ，温度为30℃ ，pH为7.0； 此菌株转化环己酮的产物通过GC/MS检测含有内酯，表明此菌株能够催化Baeyer-Villiger氧化反应；此菌株还能够以与环己酮有相似结构的环己烷，环戊酮等作为唯一碳源生长，说明此菌株底物利用范围比较广，用途比较广泛。 Baeyer-Villiger oxidation is an important chemical conversion, its products and intermediates can be used to produce a lot of medicine and fine chemicals. Its success is largely due to its versatility: a variety of carbonyl compounds can be oxidized, a large number of functional groups are tolerated, the regiochemistry is highly predictable and so on, but the oxidants that the traditional chemistry way needs have a number of problem in their production, storage, transportation and reaction, Chemistry way has not a high stereochemistry yet. However, biotransformations have many attractive characters, such as substrate-, stereo-, chemo- and enantioselectivity, so it has a great advantage in the fine chemical industry and has a bright prospect in the industrial biological catalysis. In order to study Baeyer-Villiger oxidation, we isolated a strain which can utilize cyclohexanone as sole carbon source and had a primary research on it. Its product was identified by GC/MS. Effects of pH, volume, concentration of cyclohexanone, cultivating time, temperature and rotate speed on the growth of bacteria were discussed, and the other organic substrates were also studied. The strain was identified as Plesiomonas sp.. The result of orthogonal test made it sure that the best growth condition of the strain is: rotate speed 150 rpm, temperature 30℃, pH7.0, concentration of cyclohexanone1ml/L. There is caprolactone in the product of the fermentation with cyclohexanone as substrate by GC/MS,which indicated that the strain can catalyse Baeyer-Villiger oxidation.In addition,the strain can utilize other organic substrates having the similar structure with cyclohexanone such as cyclohexane, cyclopentanone, Swertiamarin as sole carbon source.So the strain can be applied extentively.

带电粒子辅照生物分子改性的研究

本文是从超低能（110KeV）、低能（1-20MeV/u）重离子注入生物材料引起突变效应及其机理研究中产生的新生长点，从辐射化学角度通过对脱氧核糖核酸（DNA）、蛋白质以及组成DNA和蛋白质的基本单元的辐照损伤的调研，从物理角度对带电粒子（包括质子和重离子）高低传能线密度（LET）辐射与X射线、γ射线等低LET辐射加以比较，提出了采用带电粒子注入生物分子改性研究的新思路；并在此基础上，开展了一些实验工作。 在用质子束注入的甘氨酸水溶液的辐照产物的分析实验中，用气相色谱和质谱（GC-MS）联用技术的分析，得到了不同于X射线、γ-射线辐照甘氨酸水溶液的辐照产物——甘氨酰甘氨酸（甘甘二肽），并根据有关文献提出了产生这种产物的可能机理。从而从辐射化学方面为带电粒子对生物分子的辐照损伤反应提供了进一步的认识，也为从辐射生物学角度解释带电粒子对蛋白质这样大分子的作用机制提供了新的依据。

Characterization of complex hydrocarbons in cigarette smoke condensate by gas chromatography-mass spectrometry and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry

Gas chromatography-mass spectrometry with electron ionization and positive-ion chemical ionization and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC x GC-TOF-MS) were applied for the characterization of the chemical composition of complex hydrocarbons in the non-polar neutral fraction of cigarette smoke condensates. Automated data processing by TOF-MS software combined with structured chromatograms and manual review of library hits were used to assign the components from GC x GC-TOF-MS analysis. The distributions of aliphatic hydrocarbons and aromatics were also investigated. Over 100 isoprenoid hydrocarbons were detected, including carotene degradation products, phytadiene isomers and carbocyclic diterpenoids. A total of 1800 hydrocarbons were tentatively identified, including aliphatic hydrocarbons, aromatics, and isoprenoid hydrocarbons. The identified hydrocarbons by GC x GC-TOF-MS were far more than those by GC-MS. (C) 2004 Elsevier B.V. All rights reserved.

稠油高效降解菌的降解特性及其应用

以稠油为唯一碳源,对细菌B0501、B0505和B0510的降解特性进行了分析,结果表明3株菌对稠油的不同组分具有不同程度的降解能力,其中B0505对烷烃、B0510对芳香烃以及B0501对胶质和沥青质的去除率较高,分别为42.26%、35.30%和40.76%;混合菌协同作用强化了稠油组分的降解,3株菌株组合对烷烃、芳香烃以及胶质沥青质的降解率分别达到44.23%、38.56%和62.12%;微生物对稠油降解过程符合一级动力学方程,其中3株菌株组合对稠油降解的速率最快,半衰期(t1/2)为5.36 d。将微生物应用于稠油废水处理实践,结果表明外源微生物的投加强化了废水中COD的去除率;GC-MS图谱及降解前后有机成分分析进一步佐证了微生物对稠油废水中有机成分的降解能力。

苜蓿化感作用的初步研究

利用生物测定法和气相色谱 /质谱 (GC/MS)联用技术对中国北方广为种植的紫花苜蓿的化感作用进行了初步研究。结果表明 ,紫花苜蓿全草的水和 95 %乙醇浸提液对玉米和小麦种子萌发均有显著的抑制作用 ,进一步用柱层析对苜蓿浸提液进行了初步分离 ,分离组份对玉米和小麦种子萌发的影响有所变化。抑制玉米萌发的活性物质主要在弱极性的二氯甲烷组份中 ,而抑制小麦萌发的活性物质不仅存在于二氯甲烷组份中 ,也存在于水中。采用GC/MS技术 ,初步推测苜蓿的化感物质是酚和皂甙两类化合物

植物挥发性单萜经土壤载体的化感作用——以三裂叶豚草(AmbrosiatrifidaL.)为例

植物释放的挥发性单萜在生态系统中起着重要的作用,这些单萜不仅能以空气为载体对其他植物显示直接的化感作用,而且也能以土壤为载体进行间接的化感作用。通过对三裂叶豚草挥发物对植物种子萌发和土壤微生物种群影响及其化学成分的鉴定研究,验证了以单萜类物质为主的三裂叶豚草挥发物可以经土壤载体对其他植物及土壤微生物显示化感效应。还对植物挥发物化学成分鉴定的GC(气相色谱)和GC-MS(气相色谱-质谱联用)方法存在的一些误区进行了澄清,这将有助于对生态系统中植物挥发物化感作用的研究和认识。

麻黄-甘草药对配伍前后主要药效成分及抗炎活性的变化

利用高效液相色谱串联质谱联用法(HPLC-MS/MS)和气相色谱质谱联用法(GC-MS)分析了麻黄与甘草药对配伍前后水煎液中主要药效成分的变化,并通过小鼠的耳廓肿胀试验考察了甘草、麻黄单煎液及药对共煎液的抗炎活性变化。分别通过HPLC法和GC-MS法对甘草与麻黄中主要化学成分,甘草酸、甘草苷、麻黄碱和甲基麻黄碱进行了定量分析,通过单煎液和药对共煎液的对比,发现麻黄与甘草配伍共煎液中麻黄碱(含伪麻黄碱)的含量增加了14.52%;甲基麻黄碱(含甲基伪麻黄碱)的含量增加了64.0%;甘草酸含量增加了13.50%;而甘草苷含量降低了19.38%。药效实验证明,甘草与麻黄配伍后抗炎作用较甘草麻黄单煎液明显增强。从而在主要成分的变化程度上揭示了甘草与麻黄配伍过程中的增效机理。

The combined catalytic action of solid acids with nickel for the transformation of polypropylene into carbon nanotubes by pyrolysis

The effects of both organically modified montmorillonite (OMMT) and Ni2O3 on the carbonization of polypropylene (PP) during pyrolysis were investigated. The results from TEM and Raman spectroscopy showed that the carbonized products of PP were mainly multiwalled carbon nanotubes (MWNTs). Surprisingly, a combination of OMMT and Ni2O3 led to high-yield formation of MWNTs. X-ray powder diffraction (XRD) and GC-MS were used to investigate the mechanism of this combination for the high-yield formation of MWNTs from PP. Bronsted acid sites were created in degraded OMMT layers by thermal decomposition of the modifiers. The resultant carbenium ions play an important role in the carbonization of PP and the formation of MWNTs. The degradation of PP was induced by the presence of carbenium ions to form predominantly products with lower carbon numbers that could be easily catalyzed by the nickel catalyst for the growth of MWNTs. Furthermore, carbenium ions are active intermediates that promote the growth of MWNTs from the degradation products with higher carbon numbers through hydride-transfer reactions. The XRD measurements showed that Ni2O3 was reduced into metallic nickel (Ni) in situ to afford the active sites for the growth of MWNTs.

气相色谱-质谱中定量分析技术的应用

本文对气相色谱 -质谱 (GC- MS)定量分析技术及其在我国的应用进行了综述 ,较详细地阐述了峰匹配、质量色谱和选择离子检测 3种定量分析方法与应用 ,共引用文献 39篇

西洋参多糖PPQI-1～4的分离和表征

为研究生物活性西洋参多糖的性质 ,采取热水提取乙醇分级沉淀、葡聚糖凝胶分离等手段从西洋参根中分得 4个纯多糖 (PPQI- 1～ 4)。基质辅助激光解吸电离质谱 (MAL DI- MS)测定分子量 ,乙酰化衍生结合GC分析测定糖组成。甲基化结合 GC- MS分析测定糖苷键连接位点。结果表明 ,这 4个多糖化合物都是杂多糖 ,分别由不同比例的阿拉伯糖、半乳糖、葡萄糖、糖醛酸组成 ,糖醛酸含量为 30 %～ 6 0 % ,分子量范围 2～ 7万

人参茎叶挥发油中倍半萜烯化合物的分离与鉴定

对人参茎叶挥发油的有效成分进行分离纯化 ,利用薄层层析 (TL C)、红外光谱 (IR)、气相色谱 (GC)、气相色谱 -质谱 (GC/MS)联机技术从该挥发油中分离鉴定 6个倍半萜烯类化合物 .

气提法富集气相色谱／质谱法测定水中痕量挥发有机物

作者改进了气提法富集水中痕量挥发性有机物装置。研究了实验条件对水中痕量有机物富集的影响，并确定了最佳富集条件。以气提法富集气相色谱／质谱法（ＧＣ／ＭＳ）测定了水样中痕量挥发性有机物，取得了满意的结果。

快原子轰击质谱直接分析山核桃油中的混合甘油三酸酯

本文利用快原子轰击质谱(FABMS)直接测定山核桃油中未经任何前处理的混合甘油三酸酯,能获得其分子量和碎片结构信息,在GC和GC/MS分析的基础上。根据FABMS测得的分子量可推导出甘油三酸酯的组成和不同甘油三酸酯的含量。FABMS定量结果和GC、GC/MS测定结果及文献值相符。

STRUCTURE INVESTIGATION OF TI(OBU)4-ALET3 CATALYST BEFORE AND AFTER HEAT-TREATMENT

The catalyst structure of Ti(OBu)4-AlEt3 at different Al/Ti ratios before and after heat aging has been investigated from the data of UV, GC-MS, ESR and C-13 NMR spectra. The complex compounds formed by HTiEt2 and AlEt2(OBu) exist mainly in the catalyst solution, and no -OBu ligands linking with Ti atoms can be found at an Al/Ti ratio of four before heat aging. Many kinds of catalytic species with different size are formed after heat aging the catalyst at 110-degrees-C for 2 h. Dehydrogenation, accompanied by the valence change from Ti3+ to Ti2+, is observed during the aging process of the catalyst.

乙烯基三甲基硅烷等离子体聚合反应历程

应用色谱—质谱(GC-MS)及裂解色谱-质谱(PGC-MS)测定了乙烯基三甲基硅烷等离子体聚合反应中的气体冷凝物及聚合物,研究推导了等离子体聚合反应历程。单体在气相中被电子撞击,然后扩散到基底,在基底发生链增长和链终止反应。