毒素肽αB-VxXXIVA片段化学合成及质谱分析

芋螺毒素能够选择性作用一系列离子通道和受体,使其作为一类重要工具广泛应用于神经系统研究。发现于旗帜芋螺的芋螺毒素αB-VxXXIVA能够作用于α9α10乙酰胆碱受体,具有重要的药用潜能。本研究通过化学手段合成αB-VxXXIVA重要序列片段,优化其线性肽合成后氧化折叠方法。同时通过电喷雾离子阱飞行时间串联质谱诱导碰撞解离分析线性肽和折叠肽的二级质谱碎片离子峰,根据y和b系列离子分布分析其二级质谱解离规律。实验结果显示铁氰化钾氧化体系能够显著提高氧化折叠产率。二级质谱离子峰显示线性肽中y离子占主要部分,同时线性肽产生y碎片离子明显多于氧化态,长链多肽也不适用串联质谱从头测序。     

UPLC-Q-TOF/MS鉴定药用溴化丁基橡胶中未知可提取物

采用LCMS-9030超高效液相色谱串联四极杆飞行时间质谱联用仪(UPLC-Q-TOF/MS),对药用溴化丁基橡胶中未知可提取物进行鉴定,一级质谱高准确度的测定(相对误差1 ppm)确定了未知物的分子式,通过对二级质谱碎片的测定和关键碎片峰的精确区分,推断未知物的主要官能团和碳骨架。手动解谱与ACDLabs软件解析结果一致,未知物为9,10-二羟基硬脂酸。利用高特异性和灵敏度的分析技术,进一步提高了对药品包装系统的适用性的考察能力。     

血中非那西丁的GC/MS检测

建立了非那西丁的气相色谱/质谱/质谱(GC/MS/MS)联用检测血中去痛片的主要代谢物非那西丁的新方法。采用液液提取法,用乙醚提取血中非那西丁,提取物水浴浓缩后进行GC/MS和GC/MS/MS分析,检测总离子流色谱(TIC)和一级质谱,并以非那西丁一级质谱基峰为母离子的测定其二级质谱,体内药物用GC/MS全扫描定性分析即用二级质谱结合其总离子流色谱峰的保留时间定性;选择离子扫描定量分析,采用内标曲线法,根据非那西丁和内标SKF525A二级质谱的TIC峰面积比进行定量分析。     

有机质谱学基础(二)

三、有机质谱中离子的类型及其和分子结构的关系当一种有机化合物进入质谱计后,经电子束的轰击,可以生成各种类型的离子,简单地表示即: 过程(1)形成分子离子;过程(2)到(5)形成碎片离子;过程(6)为重排后得到的碎片;过程(7)为分子离子和分子碰撞后产生的离子,这种离子大于原来的分子。分子离子和分子的碰撞是属于二级反应,在通常所用的样品压力下,这一反应可以忽视。因而在一张质谱图中一般会出现分子离子峰、碎片离子峰、重排离子峰,此外还会出现由同位素引起的同位素峰和由亚稳跃迁引起的亚稳峰。     

血中非那西丁的GC/MS检测

建立了非那西丁的气相色谱/质谱/质谱(GC/MS/MS)联用检测血中去痛片的主要代谢物非那西丁的新方法。采用液液提取法,用乙醚提取血中非那西丁,提取物水浴浓缩后进行GC/MS和GC/MS/MS分析,检测总离子流色谱(TIC)和一级质谱,并以非那西丁一级质谱基峰为母离子的测定其二级质谱,体内药物用GC/MS全扫描定性分析即用二级质谱结合其总离子流色谱峰的保留时间定性;选择离子扫描定量分析,采用内标曲线法,根据非那西丁和内标SKF525A二级质谱的TIC峰面积比进行定量分析。     

头孢地嗪水溶液中降解杂质成分的检测及表征

应用超高效液相色谱串联质谱法分析头孢地嗪水溶液降解杂质成分。头孢地嗪水溶液经加热、酸碱及氧化破坏后,采用UPLC-MSE方法检测标准品及降解水溶液中杂质。依据保留时间、一级质谱母离子峰、二级质谱特征碎片分析确定头孢地嗪水解产物为反式异构体、Δ3异构体或其他降解杂质,加热、酸碱和氧化均会使杂质含量增加。头孢地嗪对热、酸、碱及氧均不稳定,样品应于暗晾干燥处密封保存,且注射溶液配制后应尽快使用。     

高效液相色谱-电喷雾电离质谱法分析人参皂甙

利用反相高效液相色谱-电喷雾电离质谱(HPLC-ESI/MS)方法,分离分析了人参皂甙。液相色谱采用乙腈-水流动相进行梯度洗脱,质谱法利用电喷雾电离质谱(ESI/MS)研究了3种人参皂甙的一级质谱(主要给出分子量)和二级、三级质谱(提供碎片离子信息),并通过质谱图的差异对其结构进行了鉴别,建立了高效液相色谱-质谱联用法分析人参皂甙的方法。     

SiO2表面原位接枝聚环氧丙烷高分子刷的制备及表征

通过“Stober”法制备出单分散球形SiO₂粒子,并采用3-缩水甘油醚氧基丙基三甲氧基硅烷对其表面进行功能化修饰,然后,利用异丙醇铝作为多相催化剂,原位引发环氧丙烷（PO）单体开环聚合,制得了聚环氧丙烷（PPO）高分子刷接枝改性的SiO₂（PPO-g-SiO₂）。研究了单体添加量、反应温度及反应时间等因素对聚环氧丙烷高分子刷接枝量的影响规律。采用红外光谱（FT-IR）、X射线光电子能谱（XPS）、透射电子显微镜（TEM）、扫描电子显微镜（SEM）及热重分析（TGA）等分析方法对制备的PPO-g-SiO₂的化学结构、微观形貌以及接枝量进行了表征。结果显示,当单体添加量为2.38 mol·L^-1,反应温度为80℃,反应时间为24 h时,PPO在SiO₂表面的接枝量可达23.56%（质量分数）;其厚度约为15 nm。     

中药黄芪中异黄酮苷类化合物的高效液相色谱-串联质谱分析

利用高效液相色谱-大气压化学电离质谱联用技术,建立了黄芪提取物中的有效成分毛蕊异黄酮-7-O-β-D-葡萄糖苷和芒柄花素-7-O-β-D-葡萄糖苷的定性分析方法。这两个化合物在大气压化学电离质谱条件下,质谱裂解行为的研究表明,二者具有相似的特征质谱裂解行为,即在正离子模式下的一级质谱中均产生强的准分子离子[M+H]+峰和苷元离子[M+H-G lu]+峰;且苷元离子经碰撞诱导解离均产生.CH3(15 Da)、CH3OH(32Da)和2CO(56 Da)的中性丢失;同时发生Retro-D iels A lder(RDA)裂解反应,导致在毛蕊异黄酮-7-O-β-D-葡萄糖苷和芒柄花素-7-O-β-D-葡萄糖苷的二级质谱图中分别产生相对分子质量为m/Z148和m/Z133的特征碎片离子峰。这些特征碎片可以作为这两个化合物定性的依据。该方法已成功应用于黄芪注射液中的这两种物质的定性分析。     

RDX和HMX的大气压电喷雾电离质谱分析

用液相色谱-大气压电喷雾电离-质谱（LC-ESI-MS）联用技术分离检测RDX和HMX混合物。由反相高效液相色谱法在C18柱上分离了RDX和HMX,检测在225nm处进行,流动相为甲醇／水（V（甲醇）：V（水）=50：50）,流速为0．2mL／min。分析了影响结果的因素,研究了通过诱导碰撞裂解（CID）电压调节RDX和HMX特征碎片离子的毛细管出口（CapEx）电压、pH值、电离方式和干燥气体温度等对其质谱图的影响。结果表明,用负离子检测模式,当CapEx电压为-100V、pH值为8时,可以得到比较理想的质谱图,可观察到RDX和HMX分子离子峰[M-H]^-、加合离子[M-H＋H2O]、[M-H＋2H2O]^-、[M-H＋NO2]^-、[M-H＋62]^-和其他特征碎片离子。根据CID技术得到的RDX和HMX的分子离子,加合离子和特征碎片离子,易确定RDX和HMX的结构。     

Thermal and NMR Studies of Polystyrene Blends

Abstract

The effect of addition of poly (propylene oxide) (PPO) and polystyrene with low molecular weight (LPS) to polystyrene (PS) was investigated blending these polymers in a Haake internal mixer. The PPO and LPS range was established up to 10% by weight. The blends were analysed by differential scanning calorimetry (DSC) and carbon-13 nuclear magnetic resonance spectroscopy at solid state (NMR), using conventional NMR techniques as cross-polarisation/magic angle spinning (CP/MAS) and proton spin-lattice relaxation time in the rotating frame (T ₁ ^H _p ). The addition of 1 and 5% of PPO and 5% of LPS to PS made the blends of PS/PPO and PS/LPS more rigid.     

Mass spectral characterization of the thermal degradation of poly(propylene oxide) by electrospray and matrix-assisted laser desorption ionization

The thermal degradation of poly(propylene oxide) (PPO), M_n = 2000, can be characterized by electrospray (ESI) and matrix-assisted laser desorption ionization (MALDI). ESI and MALDI spectra of partially degraded PPO provide strong support for the thermal degradation pathway previously suggested by Griffiths et al. and Lemaire et al. Although these pathways differ in detail, it is not possible to distinguish between them from the masses of the resultant degradation species. Gel permeation chromatography data indicate that both mass spectrometric methods emphasize the presence of low-mass material, particularly in the degraded samples. This is attributed to the different sensitivities of the two techniques and some in situ fragmentation during mass spectrometric analysis.     

The preparation of microporous membranes from blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide) and sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) is a chemically resistant polymer and, therefore, an attractive material for the formation of membranes. However, membranes of unmodified PPO prepared by an immersion precipitation possess very low hydraulic permeabilities at the filtration processes. The membranes with higher hydraulic permeabilities can be prepared from sulfonated PPO and/or from blends of unsulfonated PPO and sulfonated PPO. In conclusion, the mechanism of the formation of membranes from blends of unsulfonated PPO and sulfonated PPO is suggested. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 161–167, 1999     

Properties and radiation resistance of aromatic polymer-based polyblends

Blends of either of two different poly(phenylene oxide) (PPO) derivatives with poly(2-vinylnaphthalene) (P2VN) were prepared by casting from chloroform. The content of P2VN in the blends ranged from 0 to 25 wt % for each PPO derivative. Two kinds of PPO derivatives, p–t-butylbenzoyl poly(phenylene oxide) (p–t-BB-PPO) and benzoyl poly(phenylene oxide) (B-PPO), were used. The effects of the addition of P2VN to PPO derivatives were investigated by their thermal stability, light-resistance, and tensile properties. Even though the addition of P2VN to the PPO derivatives decrease the mechanical properties, the radiation resistance was improved. The radiation resistance and tensile properties of B-PPO and its blends with P2VN were higher than those of the p–t-BB-PPO and its blends with P2VN. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1697–1705, 1999     

纳米SiO2对聚苯醚树脂/氰酸酯复合材料性能的影响

以聚苯醚树脂(PPO)改性BCE(双酚A型氰酸酯)作为复合材料的基体树脂,以硅烷偶联剂(KH-560)处理过的纳米二氧化硅(nano-SiO2)作为改性剂,制备出nano-SiO2/PPO/BCE复合材料.结果表明:适量的nano-SiO2既可同时提高PPO/BCE体系的韧性和强度,又可改善其介电性能和吸湿性能;当w(...     

Column fractionation of partially stereoregular poly(propylene oxide)

A column packed with glass beads has been used to fractionate partially stereoregular poly(propylene oxide) (PPO). PPO was first crystallized onto the glass beads from isooctane solution by stepwise lowering the column temperature. Each layer of PPO, which was deposited at different temperature ranges, was extracted by washing the beads with several columns full of isooctane. Thus several fractions differing in both stereoregularity and molecular weight were obtained by progressively increasing the extraction temperature and the solvent residence time in the column. It is concluded that in the procedure described above PPO can be fractionated on the basis of structural and steric regularity. The observed steady increase in the molecular weight of fractions with extraction temperature was interpreted as being due to the fact that the stereoregularity of chains increases with their molecular weight.     

3，3’-二乙基-4，4’-二苯甲烷型多马来酰亚胺／聚苯醚树脂的固化反应研究

热固性聚苯醚(PPO)已成为高性能印制电路板用树脂(PCB)发展的主流。本课题组的前期研究表明,3,3,-二乙基-4,4,-二苯甲烷型多马来酰亚胺(PEDM)/烯丙基化PPO是一种新型高性能PCB用树脂。文章采用红外光谱和裂解气相色谱,对PEDM的含量为PPO 10%的PEDM/烯丙基化PPO树脂的固化反应进行研究,结果表明,PEDM分子的不饱和双键与PPO的烯丙基和羟基在加热过程中发生了反应。     

PPO–PC block‐copolymers used as compatibilizers in PS/PC blends

Block‐copolymers containing poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) and polycarbonate of bisphenol A (PC) segments were employed as compatibilizers in polystyrene (PS)/PC blends. Block‐copolymers were prepared starting from oligomeric diols‐terminated PPO and PC. The poly(phenylene ethers) was obtained by oxidative coupling of 2,6‐dimethyl‐phenol in presence of tetramethyl bisphenol A. The copolymers were obtained with a chain extension reaction between the starting oligomers using bischloroformate of bisphenol A or phosgene as coupling agent. PS/PC blends, cast from chloroform solutions or mixed by melt, were studied by differential scanning calorimeter (DSC), dynamic‐mechanical thermal analysis (DMTA), and optical microscopy (OP). The thermal and morphological analyses showed a clear compatibilization effect between PS and PC, if PPO–PC copolymer is added when blending is performed in the melt; in addition, also mechanical properties are increased when compared with blends without PPO–PC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4654–4660, 2006     

聚苯醚的改性

综述了改性聚苯醚（ＰＰＯ）的研究开发及其性能和应用情况,并提出了ＰＰＯ的发展特点和前景。     

Synthesis and properties of hydrophilic segmented block copolymers based on poly(ethylene oxide)‐ran‐poly(propylene oxide)

The present article discusses the synthesis and various properties of segmented block copolymers with random copolymer segments of poly(ethylene oxide) and poly(propylene oxide) (PEO‐r‐PPO) together with monodisperse amide segments. The PEO‐r‐PPO contained 25 wt % PPO units and the segment presented a molecular weight of 2500 g/mol. The synthesized copolymers were analyzed by differential scanning calorimetry, Fourier transform infra‐red spectroscopy, atomic force microscopy and dynamic mechanical thermal analysis. In addition, the hydrophilicity and the contact angles (CAs) were studied. The PEO‐r‐PPO segments displayed a single low glass transition temperature, as well as a low PEO crystallinity and melting temperature, which gave enhanced low‐temperature properties of the copolymer. The water absorption values remained high. In comparison to mixtures of PEO/PPO segments, the random dispersion of PPO units in the PEO segments was more effective in reducing the PEO crystallinity and melting temperature, without affecting the hydrophilicity. Increasing the polyether segment length with terephthalic groups from 2500 to 10,000 g/mol increased the hydrophilicity and the room temperature elasticity. Furthermore, the CAs were found to be low 22–39° and changed with the crosslink density. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117:1394–1404, 2010