苦参生物碱电喷雾质谱分析

用电喷雾离子阱质谱(ESI-ITMS)研究了苦参碱和氧化苦参碱一级质谱电离规律和二级质谱裂解规律。实验结果显示,苦参碱和氧化苦参碱电喷雾一级质谱中均易产生聚合及加合离子,二级质谱中易产生环逐步裂解碎片离子,即结构相似的苦参碱和氧化苦参碱具有相似的电喷雾质谱行为。苦参碱的特征碎片为m/z148和150,氧化苦参碱的特征碎片为m/z248([M H-17] )、m/z247([M H-18] )以及m/z148、m/z150。对苦参对照药材的甲醇提取物进行了电喷雾质谱分析,由一级质谱的准分子离子及其二级质谱碎裂信息对各已知组分进行了结构认证。     

表面活性剂的电喷雾质谱分析

采用不同的质谱采集模式分析了不同类型的表面活性剂。阳离子表面活性剂如氯化十二烷基二甲基苄基铵,适合正离子采集模式,准分子离子为其阳离子;阴离子表面活性剂如十二烷基苯磺酸钠,适合负离子采集模式,准分子离子为其阴离子;两性表面活性剂如氧化十四烷基二甲基胺,适合负离子采集模式,准分子离子为[M-H]^-;非离子表面活性剂如壬基酚聚氧乙烯（12）醚,适合正离子采集模式,准分子离子为[M＋Na]^-。     

土壤中一种新的尿素衍生物的电喷雾萃取电离质谱分析

采用电喷雾萃取电离串联质谱(EESI-MSⁿ)技术直接分析马尾松根际土壤溶液, 发现了一种不稳定的尿素衍生物3,3-二氨基-3-羟基丙酸. 为确证其结构, 以尿素为原料合成了该衍生物, 并采用EESI-MSⁿ分析合成产物. 结果表明, 合成产物与土壤溶液中的3,3-二氨基-3-羟基丙酸的EESI-MSⁿ分析结果相吻合, 说明土壤中确实存在该衍生物, 其可能是一种尿素在土壤里代谢过程的中间体. 本文结果表明, EESI-MS技术可以直接分析复杂基体样品中痕量物质的信号, 为研究尿素在土壤中的氮素转化机理提供了新的思路.     

芦丁的电喷雾离子阱质谱分析

研究了芦丁在电喷雾离子阱质谱(ESI-MS)下的主要特征碎片离子及其裂解规律。应用电喷雾离子阱质谱技术研究芦丁的结构和正、负离子扫描条件下芦丁的主要特征碎片离子及其裂解规律。芦丁在正、负离子模式下均可得到较好的质谱信息,在正离子模式下,容易与Na+形成[M+Na]+的准分子离子,并裂解形成碎片m/z 605,487,331,325,313,185等,在负离子模式下,形成[M-H]-的准分子离子,并进一步碎裂形成碎片m/z 301,283,257,255,229,227,211等。分别阐明了芦丁在正、负离子模式下的电喷雾质谱碎裂规律,并对主要特征碎片离子进行归属,为进一步芦丁的结构优化和修饰提供了有价值的依据。     

非共价复合物的电喷雾质谱分析

非共价复合物一直是质谱分析的难点,因为这些复合物大多以氢键、范德华力、疏水作用、静电作用、金属配位作用等非共价弱键形成,常规质谱相对过于剧烈的离子化条件不利于非共价复合物的检测.但由于在许多生命现象、药物筛选以及超分子化合物中都涉及到分子之间的相互作用以及相互识别过程,而且人们普遍认识到非共价复合物是这些过程形成的基础,因此许多科学工作者都致力于非共价复合物该前沿课题的开发研究,并且迫切需要发展一种分析工具来辅助解析这种现象.电喷雾离子化(ESI)技术作为一种"软"电离技术,以及它在分析极性生物大分子中得天独厚的优势,近年来被广泛的应用在非共价复合物研究上.国内由于生物质谱技术起步较晚,这个领域至今没有获得充分的发展,本论文在ESI正交离子引入飞行时间质谱上,开展了非共价复合物分析的一些初步研究.     

一种聚酰胺-胺型树枝状分子的电喷雾离子阱质谱分析

以己二胺为分子内核,室内合成了一类支化代数为1.0G的聚酰胺-胺型树枝状分子己二胺四丙酰胺二胺(1.0G支化物)。应用ESI-MS技术研究并表征了该支化物的分子结构与正、负离子扫描条件下的主要特征碎片离子及主要裂解途径。1.0G支化物在正、负离子模式下均可以得到较佳的质谱信息。在正离子模式下,容易与H+形成[M+H]+准分子离子,并裂解形成碎片m/z573.41,m/z 555.40,m/z 471.30,m/z 459.30,m/z 453.28,m/z 369.17,m/z357.16等。在负离子模式下丢失一个H+,形成[M-H]-准分子离子,并进一步碎裂成碎片m/z 571.43,m/z 511.29,m/z 457.20,m/z 397.05,m/z 342.99,m/z240.84等。分别阐述了1.0G支化物在正、负离子模式下的电喷雾质谱裂解规律并对主要特征碎片离子进行了结构归属,为进一步对聚酰胺-胺型树枝状分子的表征与结构指认提供了有价值的依据。     

直接进样电喷雾质谱分析烷基苯磺酸盐

采用直接进样法，电喷雾质谱分析三次采油用烷基苯磺酸盐，可以得到定性结果，定出该表面活性剂中各组分的分子式，操作简单易行．     

中性富勒烯分子的直接电喷雾质谱分析

电喷雾电离是新近发展的一种质谱技术, 适用于分析在溶液中呈离子状态的物质, 具有无碎片的特点。本文根据富勒烯分子的电子亲和性能, 将富勒烯混合物的甲苯溶液直接进行电喷雾质谱分析, 检出了C60, C70, C76, C80, C82, C84, C86,C88, C90, C92, C94和C96等的负离子峰。并用萘钾作还原剂,将富勒烯混合物预先还原, 制得富勒烯负离子溶液后再作电喷雾质谱分析, 得到相同的结果。表明各类富勒烯分子在电喷雾过程中俘获电子的能力与被萘钾还原的能力相一致。     

烷基苯磺酸盐的电喷雾离子化质谱和碰撞活化解离质谱－质谱分析

用正,负电喷雾电离（ESI）并结合碰撞活化解离（CAD）质谱法对烷基苯磺酸盐（ABS）进行鉴定,无论正,负离子化过程中均不出现快原子轰击质谱常见的碎片峰,由于没有复杂碎片峰的干扰,ESI－MS对分析ABS试样大为有利,正离子ESI－MS对支化ABS鉴定的灵敏度远低于负离子ESI－MS,用CAD－MS对ESI－ME谱各主要峰进行了归属,线型与支化ABS相对含量可以用负离子ESI－MS求出,负离子化ESI－MS是快速,有效和可靠的鉴定,ABS的方法。     

有机锡化合物的电喷雾电离质谱

报道了一系列有机锡ＲＲＰ（Ｓ）ＳＳｎ（Ｃｙ）３化合物的电喷雾电离质谱（ＥＳＩ－ＭＳ）及碰撞诱导解离质谱（ＣＩＤ－ＭＳ）,总结了其谱图特征,讨论了其碎裂机理,为该类化合物的鉴定提供了依据。     

氨基酸与钠离子非共价键相互作用的电喷雾质谱研究

实验研究中常常观察到钠离子与一些多肽或蛋白质有较强的非共价键结合能力,这种非共价键相互作用可能与生物的一些功能和活性有关。为了进一步了解这一结合作用,我们应用电喷雾质谱研究了常见的20种氨基酸与钠离子在溶液中的非共价键相互作用。实验研究中发现脯氨酸和苯丙胺酸与钠离子有较强的非共价键结合能力。     

电喷雾质谱在非共价蛋白复合物研究中的应用

综述了近些年来电喷雾质谱在研究蛋白质高级结构中的应用及发展,尤其是电喷雾质谱测定非共价键结构的进展。     

Exploratory study of the reaction of bis(2-methoxyethyl)aminosulfur trifluoride (Deoxofluor™ reagent) with diaryl sulfoxides: novel routes to Ar2SF2 and Ar2SF(OTf) via sulfoxide activation

Neither bis(2-methoxyethyl)aminosulfur trifluoride (Deoxofluor™ reagent) nor HF/pyridine alone can fluorinate diaryl sulfoxides. S-fluorination can be effected by activating the sulfoxide via protonation with HF/pyridine (70:30) to form sulfoxonium ions in equilibrium which are then S-fluorinated in situ with Deoxofluor™ to give Ar₂SF₂ compounds. Conversions depend strongly on steric factors and the reactions require the use of excess Deoxofluor™ and HF/pyridine. NMR data for the resulting diarylsulfur difluorides are gathered and discussed. Sulfoxide activation via diaryl (trifloxy) sulfonium triflate generated in situ from Ar₂SO with triflic anhydride at low temperature represents another strategy for S-fluorination with Deoxofluor™ to generate Ar₂S(OTf)F.     

ESI-MS quantitation of iron as its 4-(2-pyridylazo)resorcinol (PAR) complex: application to pharmaceutical tablets containing iron oxide pigment

Quantitation of iron oxide (Fe(2)O(3)) in pharmaceutical formulations using electrospray ionization mass spectrometry (ESI-MS) following iron complexation with 4-(2-pyridylazo)resorcinol (PAR) was evaluated. Complexation of Fe(III) with PAR was found to produce an intense mass spectral signal at low pH compared to the free ligand. Using the selected-ion-monitoring mode of a triple-quadrupole mass spectrometer, the signal at m/z 484 arising from the singly charged [Fe(III)(PAR)(2)](+) complex gave a limit of detection of ~2 μM for total iron. The linear range of the calibration curve was found to be 2-43 μM total iron. Trace iron interference was decreased to submicromolar levels by performing an optimized labware cleaning protocol and instrument replumbing using Polyetheretherketone (PEEK) tubing. The validation parameters of this ESI-MS total iron analysis (specificity, linearity, precision, accuracy, robustness and stability) are within the acceptance criteria listed in the validation guidelines developed by the Food and Drug Administration for industry. Recovery of 93% of the added iron indicated a satisfactory extraction procedure for tablets containing Fe(2)O(3) pigment. There was no statistical difference between the results obtained by ESI-MS and the common elemental method, inductively coupled plasma-optical emission spectroscopy. Since the proposed ESI-MS method can be performed on a mass spectrometer equipped with an ESI source, which is standard instrumentation in the pharmaceutical industry, the method validated here provides an alternate method for metal ion analysis by ESI-MS.     

高效液相色谱-电喷雾质谱联用分析兰索拉唑及其副产物

兰索拉唑(lansoprazole)为新型的抑制胃酸分泌的药物,临床上用于十二指肠溃疡、胃溃疡、返流性食管炎等的治疗,疗效显著,对幽门螺杆菌有抑制作用[1-2]。我们以2-[[[3-甲基-4-(2,2,2-三氟乙氧基)-2-吡啶基]甲基]巯基]-1H-苯并咪唑为原料,成功地制得了兰索拉唑(2-[[3-甲基-4-(2,2     

Nucleophilic fluorination of amino alcohols and diols using Deoxofluor

Various fluorinated chiral compounds were synthesized using bis(2-methoxyethyl)aminosulfur trifluoride (Deoxofluor) as a nucleophilic fluorinating reagent. Reactions of Deoxofluor (1) with amino alcohols (2a-d) and diols (2e-g) in methylene chloride at room temperature led to the formation of the corresponding fluoro derivatives (3a-g) in good yields.     

Determination of peptide hormones of brain and intestine by CE with ESI-MS detection

A new method for the determination of the peptide hormones of brain and intestine based on CE coupling with a DAD and ESI-MS was established. Several electrophoretic and ESI-MS parameters were investigated in detail, such as electrolyte nature and concentration, organic solvent and sheath liquid compositions, nebulization gas pressure and the ESI capillary voltage. Optimized conditions were achieved with 25 mM formic acid-ammonium formate (pH 2.9) as the optimal electrolyte, 2 mM formic acid in 80% methanol in water as the sheath liquid, and 20 kV applied voltage. Under the optimized conditions, four protonated peptides were separated by CE and selectively detected by a quadrupole mass spectrometer with a sheath flow ESI interface. LODs for the four peptides (neurotensin hexapeptide, neurotensin, cholecystokinin tetrapeptide, and pentagastrin) were in the range of 0.10-0.60 micromol/L at an S/N of 3. The RSDs (n = 8) of the method were 0.70-1.5% for migration times and 1.6-6.1% for peak areas. This method is simple, rapid, and selective compared with RIA and ELISA techniques, and has been applied to the analysis of rat hypothalamus tissue.     

LC-ESI-MS分析两性霉素B降解产物

两性霉素B(amphotericinB)是一种常用的抗真菌抗生素,属于多烯大环内酯类化合物,化学性质不稳定,在生产和储存过程中容易发生多种降解反应,产生无活性甚至有毒性的降解物,直接影响产品质量和临床用药的安全,因此,研究该抗生素降解物和降解途径,对防止产品降解、保证产品质量非常必要。已有不少有关两性霉素B各种剂型稳定性的研究报道,ThomaK等研究报道了多烯类抗生素光稳定性结果,然而有关两性霉素B在酸、碱、加热、氧化和光照等条件下降解途径研究未见报道。由于直接分离鉴定各降解产物比较困难,本实验采用LC-MS在线分析手段,直接分析检测降解产物。实验表明,通过检测各种加速实验样品的降解物,可以确立降解途径和降解物,本文对控制降解反应发生、提高产品质量以及稳定性研究具有重要意义。     

An effective new access to ethyl 2-[(alkylamino)(cyano)methyl] acrylates: first synthesis of ethyl 3-cyano-2-(hydroxymethyl) acrylate

A regioselective coupling of ethyl 2-(bromomethyl)-3-cyanoacrylate and primary amines is described to give ethyl 2-[(alkylamino)(cyano)methyl] acrylates in good yields. Whereas the conversion of allyl bromide in the presence of TEAF leads to the first synthesis of ethyl 3-cyano-2-(hydroxymethyl) acrylate.     

Bis(O-nitrophenyl) Carbonate as a New Reagent for the Synthesis of Chiral Oxazolidin-2-ones

Bis(o-nitrophenyl) carbonate reacts under mild conditions with chirals 1,2-amino alcohols and, after addition of DMAP, affords the corresponding oxazolidin-2-ones in very good yields.