The first synthesis of a water-soluble alpha-cyclodextrin/C-60 supramolecular complex using anionic C-60 as a building block

A novel supramolecular inclusion complex of alpha-CD/C-60 was synthesized using anionic C-60. The reaction progress was monitored in situ by visible and near-IR spectroscopy. The obtained complex was characterized by UV-vis, C-13 NMR, MALDI-TOF, and cyclic voltammetry. The induction and dispersion forces are considered to be the major driving forces for the formation of a resulting alpha-CD/C-60(.-) inclusion complex.

Structure of Cyclic Aryl Thioester Dimer Based on o-Phthaloyl Dichloride and Bis(4-mercaptophenyl) Sulfide

A cyclic aryl thioester dimer was prepared by the reaction of o-phthaloyl dichloride and his (4-mercaptophenyl) sulfide in good yield under pseudo-high dilution conditions via interfacial polycondensation. The structure of the cyclic dimer was confirmed by a combination of MALDI-TOF-MS, FTIR, gel permeation chromatography and MM analyses. The X-ray diffraction study of the single crystal of cyclic thioester dimer obtained from two solutions reveals no severe internal strain on the cyclic structure.

聚砜齐聚物的激光质谱分析

MALDI-TOF-MS是20世纪80年代末发展起来的一种先进的软电离技术,由于它具有质量范围宽、碎片少的优点,能够用来直接观察到一些聚合物离子,它已被成功地应用在生物高分子如蛋白质、核苷酸以及PS,PEG、树枝状聚脂、树枝状聚醚等合成高分子的表征中[1,2].另外,它也成功地应用到了芳香环状聚酯[3]、芳香环状聚酰胺[4]等芳香环状齐聚物结构表征中.本文应用了MALDI-TOF-MS法对聚砜齐聚物结构进行了表征与确认,获得了满意的结果.研究结果表明该方法是测定聚砜齐聚物结构的有效方法.

Study on a carbosilane liquid crystalline (LC) dendrimer of the first generation - Containing twelve 4-butoxyazobenzene mesogenic groups in periphery

The divergent synthesis of a new carbosilane liquid-crystalline (LC) dendrimer of the first generation (D1) is described. Twelve 4-butoxyazobenzene groups are used as mesogenic fragments and attached in the periphery of the molecule. Structure and properties of D1 were characterized by element analysis, H-1 NMR, MALDI-TOF-MS, IR, UV-Vis, polarizing optical micrograph, DSC and WAXD. It is argued that mesophase of nematic type is realized. It is shown that the mesophase type of the dendrimer essentially depends on the chemical nature of the mesogenic groups. Phase behavior of D1 is K82N1331132N67K. The melting point of D1 is 30similar to43 degreesC lower than that of M5, its clearing temperature is 9 similar to 11 degreesC higher than that of M5 and its mesophase region is enlarged by 39 similar to 54 degreesC compared to that of M5. Eight extinguished brushes emanating from a stationary point are observed, corresponding to the high-strength disclination of S = + 2 of dendrimer. The clearing enthalpy of D1 is smaller than the value that is commonly found for phase transition n-i in LC and LC polymers. This may be due to the presence of branched dendrimer cores which cannot be easily deformed to fit into the anisotropic LC phase structure.

Acid effects on protein molecular weight determination

The acid effects of some proteins on measuring their molecular weights were studied using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry ( MALDI-TOF-MS) and electrospray ionization mass spectrometry (ESI-MS). It was found that the signal intensity was enhanced through adjusting the acid concentration in some protein samples. In this paper, both MALDI-MS and ESI-MS was applied to examine the molecular weights of several standard proteins. And the proper acid concentration was detected in these spectra. In the meanwhile, it demonstrates that some associations of proteins in solution can be preserved into the gas phase and observed by the "soft ionization" mass spectrometry.

Rapid molecular weight determination of recombinant hirudin by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The molecular weight of recombinant hirudin ( rHV-2) was determined rapidly by matrix-assisted laser desorption/ionization time of fight mass spectrometry (MALDI-TOF-MS). The effects of the three types of matrixes were compared and discussed, alpha-cynao-4-hydroxycinnamic acid was proved to be the best matrix. It showed that MALDI-TOF-MS was superior to the traditional method of molecular weight determination of the biological macromolecules. The mass spectrum data proved that the primary structure of rHV-2 was correct and there was no amino acid deletion, mutation and modification in its expression, refolding and purification.

Synthesis of phenyl/amino-capped tetraaniline by chemical and electrochemical methods

Phenyl/amino-capped tetraaniline was prepared by chemical oxidation coupling and electrochemical cyclic voltammetry methods. The MacDiarmid's method of oxidation coupling was improved. The aqueous HCl was replaced with a mixture solution of HCl and acetone and (NH4)(2)S(2)O(0)8 was used as oxidant instead of FeCl3. The reaction displays a higher yield and the product tetraaniline has a higher purity owing to the improvement. In the mixture solution system, tetraaniline can be synthesized by electrochemical cyclic voltammetry method. The mechanism by which tetraaniline was prepared from p-amino diphenylamine was proposed. The product was characterized by MALDI-TOF MS and FTIR.

蛋白质分子量测定过程中的酸效应

在基质辅助激光解吸电离飞行时间质谱 (MALDI TOF MS)和电喷雾质谱 (ESI MS)测定蛋白质分子分子量的过程中 ,适当提高样品的酸度 ,可提高分析测试的灵敏度。在选定最佳样品分子浓度的基础上 ,通过适当加入三氟乙酸 (TFA)来调整测试样品的酸度 ,准确测定了标准蛋白质 溶菌酶 (lysozyme)的分子量 ,并且对蛋白质分子在“软电离”质谱中 ,受酸效应的影响进行了初步探讨

应用基质辅助激光解吸质谱快速分析重组水蛭素产物的纯度与分子量

利用MALDI TOF MS测定了具有抗凝血活性的水蛭素基因重组产物 (rHV 2 )的纯度和分子量 ,实验测定结果与理论计算值一致。证明此基因重组产物的一级结构是正确的 ,在表达、复性和纯化的过程中没有氨基酸的丢失、变异和修饰。

人参四逆汤成分的研究

利用ESI/MS~n、LC/MS、MALDI-TOF/MS等技术,从人参四逆汤水煎液中分析和鉴定了10种二萜生物碱:苯甲酰中乌头碱benzoylmesaconitine、苯甲酰乌头碱henzoylaconitine、苯甲酰次乌头碱benzoylhypacoitine、尼奥灵neoline、附子灵fuziline、14-乙酰基塔拉地萨敏14-acetyl-talatisamine、苯甲酰次乌头碱亚油酸酯14-benzoylhypaconine-8-linoleate、苯甲酰去氧乌头碱亚油酸酯14-benzoydeoxyaconine-8-oleate、苯甲酰次乌头碱棕榈酸酯14-benzoylhypaconine-8-palmitate、塔拉地萨敏talatisamine和人参皂甙R_(a1)、R_(a2)、R_(b1)、R_(b2)、R_(b3)、R_c、R_d、R_e、R_(g1)、R_(g2)、R_(g3)、R_f等12种人参皂甙。脂肪酸酯型生物碱和苯甲酰类生物碱的提取组分有抗失血性休克作用和弱的正性肌力作用。人参皂甙的提取组分具有明显的负性肌力作用。

激光解吸电离飞行时间质谱技术及应用

本文简述了激光解吸电离飞行时间质谱(NALDI-TOF-MS)技术及其应用,同时介绍了MALDI-TOF-MS的构造、原理及特点。

Analysis of monodispersed polyaniline oligomers by matrix-assisted laser desorption ionization mass spectrometry

Monodispersed polyaniline oligomers was studied by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS), It is found that MALDI-TOF-MS is not only a direct, accurate and rapid tool for the analysis of monodispersed polyaniline oligomers, but also a useful technique for the design of synthetic route.

Novel macrocyclic precursors of poly{aryl ether ketone (sulfone)} containing hexafluoroisopropylidene units: Synthesis, characterization, and polymerization

Cyclic oligomers containing hexafluoroiso-propylidene(HFIP) units were prepared in excellent yields by a nucleophilic aromatic substitution reaction of 4,4(7)- (hexafluoroisopropylidene) diphenol with difluoro-monomers in the presence of anhydrous potassium carbonate under pseudo high dilution conditions. A combination of GPC, MALDI-TOF MS and NMR analysis confirmed the structure of the cyclic oligomers. All macrocyclic oligomers are crystalline and undergo facile melt polymerization to give high molecular weight fluorinated polyethers.

Mass spectrometry study on snake venoms and enzymes

In this paper, three kinds of snake venoms and lour kinds of enzymes (phospholipase A(2), fibrinolytic enzyme, arginine esterase and L-amino acid oxidase) isolated from the snake venom were analyzed. As the snake venom was different, the MALDI/TOF/MS showed difference, The MALDI/TOF/MS determination results could be affected Ly the concentrations of snake venom enzymes, And the mechanisms of desorption and ionization was also given in this study, By using MALDI/TOF/MS we obtained the accurate molecular weights and homogeneities of the enzymes. The apparent characteristics of the positive MALDI/TOF/MS of enzymes composed by two subunits were also given out, The results showed that MALDI/TOF/MS is an effective analytic method for discovering new components from snake venom complexes. And it is reliable to use this method to determine the molecular weights and purifies of protein molecules.

Synthesis and free-radical ring opening polymerization of macrocyclic aryl thioether ether ketone (sulfone) oligomers

Two kinds of novel macrocyclic aryl thioether ether oligomers were synthesized by nucleophilic condensation reaction in high yields under pseudo-high-dilution condition. A combination of H-1 NMR, GPC and MALDI-TOF MS analyses unambiguously confirmed the cyclic nature and their distributions, Macrocyclic thioether ether ketone oligomers can undergo facile melt ring opening polymerization(ROP) initiated by thiyl radical to give a high molecular weight polymer.