纳升电喷雾串联质谱法确证阿托西班的一级结构

利用电喷雾串联质谱对合成八肽阿托西班进行了二硫键还原前后的精确分子量测定和一级结构的确证.首先通过全扫描模式测定了其还原前后的精确分子量,然后选择母离子m/z 498.73(双电荷)通过串联质谱(MS/MS)得到碎片离子,采用Y离子的方法测定了阿托西班的序列并对其的修饰位点进行了确证.本方法具有灵敏度高、速度快、样品无需纯化等特点,在多肽类药物一级结构分析方面具有独特的优势.     

基质辅助激光解析电离质谱和电喷雾质谱共同快速确证达托霉素结构

运用基质辅助激光解析电离-飞行时间串联质谱(MALDI-TOF/TOF MS)和电喷雾-四级杆-飞行时间质谱(ESI-Q-TOF MS)快速确证环脂肽达托霉素的结构。首先,ESI检测达托霉素相对分子量为1619.7107,与理论值偏差0.0007。选择其双电荷峰m/z 809.848作为母离子进行ESI串联质谱(MS/MS)测定,成功匹配了达托霉素环外氨基酸序列C9H19CO-Trp-Asn-Asp。其次,优化Li OH裂解达托霉素的实验条件,以MALDITOF/TOF MS监测开环效果,获得95%以上的开环样本后,分别运用MALDI和ESI进行MS/MS测定,达托霉素开环产物的b+和y+全部被匹配,达托霉素全部氨基酸序列得到确证。最后,对开环产物的ESI-MS/MS条件进一步优化,获得了丰富的低端碎片离子,解析了脂肪酸链结构,并绘制了脂肪酸链的裂解图。本方法快速、简便、准确,是确证环脂肽类化合物结构的可靠方法。     

阿莫西林的傅立叶变换-离子回旋共振质谱研究

阿莫西林为β-内酰胺类广谱抗菌药物,由于疗效好、安全可靠且不良反应少,成为临床上广泛应用的一线抗生素.阿莫西林颗粒U服给药,具有服用方便、患者依从性好等优点,尤其适用于儿童使用.近年部分厂家阿莫西林颗粒市售产品抽验不合格,为控制相应经营品种质量,本研究首次应用傅立叶变换离子回旋共振质谱(FT-ICR-MS)和傅立叶变换离子回旋共振串联质谱(FT-ICR-MSn,n=2)对阿莫西林产品进行分析研究,给出了阿莫西林的精确相对分子质量和串联质谱碎片的精确质量,以确证其结构.     

单克隆抗体-白介素2融合蛋白一级结构的确证

建立单克隆抗体-白介素2融合蛋白一级结构确证的方法.用基质辅助激光解吸飞行时间质谱测定单克隆抗体-白介素2融合蛋白的精确相对分子质量,毛细管等电聚焦方法测定其等电点,通过N-末端氨基酸序列的测定以及肽图分析,证实了抗体-白介素2融合蛋白一级结构表达的正确性,同时为单克隆抗体-白介素2融合蛋白的质量标准研究奠定了基础.     

反相高效液相色谱-电喷雾质谱法分析食源血管紧张素转换酶抑制肽

利用反相高效液相色谱/电喷雾离子阱质谱法,直接分析从牦牛乳酪蛋白中酶水解得到的血管紧张素转换酶抑制肽粗产物。RP-HPLC显示具有活性的多肽粗产物含有3个主要成分,质谱同步测定各组分的分子量(m/z)分别为815.2,1680.1,962.2,然后选择[M H] 离子通过串联质谱(MS/MS)得到碎片离子,利用b离子和y离子互补的方法鉴定了多肽序列。三条肽分别为Leu-Pro-Tyr-Tyr,Pro-Leu-Pro-Leu-Leu-Gln,Phe-Leu-Pro-Pro-Tyr-Tyr。结果显示,所获得的多肽序列与牛乳酪蛋白一级结构中相应肽段的序列一致。     

基于GC/Q-TOF MS技术鉴定S-zorb汽油中噻吩类化合物

结合气相色谱分离技术和MS/MS串联质谱筛查技术,通过选定目标母离子进行碰撞诱导解离,获取精确质量子离子信息,实现汽油馏分中噻吩类化合物的痕量筛查分析.选取5种不同碳数取代噻吩类化合物作为标准物绘制定量标准曲线,建立了基于气相色谱-四极杆串联飞行时间质谱(GC/Q-TOF MS)直接测定汽油中噻吩类化合物的方法.利用该...     

婴幼儿奶瓶中迁移双酚A的高效液相色谱-电喷雾串联质谱检测方法研究

建立了婴幼儿奶瓶中双酚A(BPA)迁移量的高效液相色谱-电喷雾串联质谱(HPLC-ESI-MS/MS)测定方法。奶瓶食品模拟浸泡液经过弗罗里硅土玻璃层析柱净化,高效液相色谱分离,采用选择反应性监测模式(SRM)检测。以一级质谱得到的准分子离子m/z 227作为母离子,进行二级质谱(MS2)分析。选择MS2的碎片离子m/z 212、133、93定性确证,m/z 212作为定量离子定量。实验优化了质谱条件,并对二级质谱碎裂机理和特征离子进行了研究。测定结果的相对标准偏差不大于8.2%(n=7),回收率在87.7%～105%之间;检出限为2μg/L,能够满足欧盟、美国等对奶瓶中双酚A的限制要求。该法已成功应用于婴幼儿奶瓶中BPA迁移量的测定。     

纳升电喷雾串联质谱鉴定重组人甲状旁腺素(1-34)

用先进的纳升电喷雾-四极杆-飞行时间串联质谱鉴定重组人PTH(1-34)。通过ESI-MS测定重组人PTH(1-34)分子量及MS/MS对其胰蛋白酶酶解后的肽段的序列和数据库查询进行结构鉴定。重组PTH(1-34)测定分子量为4115.21,与理论值相比测定相差0.06%。MS/MS测定出其中双电荷离子峰m/z728.4肽段序列为VSEIQLMHNLG,以及其他3个单电荷离子峰的序列。数据库检索后确定重组表达的PTH(1-34)一级结构完全正确,纳升电喷雾串联质谱以其灵敏、快速和准确为蛋白质鉴定提供了有效的手段。     

合成多肽的电喷雾质谱研究

利用电喷雾多极串联质谱对3种合成多肽进行了系统的鉴定和分析研究。首先通过全扫描模式测定了其分子量，然后选择[M H]^ 或[M 2H]^2 离子通过串联质谱(MS／MS)得到碎片离子，采用y离子和b离子互补的方法测定了多肽序列。利用文献数据对这种方法进行了验证，实验结果表明，该方法简便、快速、实用。     

高效液相色谱-串联质谱法测定纺织品中的致癌芳香胺

建立了高效液相色谱-串联质谱法(LC/MS/MS)测定纺织品中致癌芳香胺的检测方法.纺织品中的偶氮染料在柠檬酸缓冲液中用连二亚硫酸钠还原为芳香胺,用硅藻土提取还原液中的芳香胺,用乙醚洗脱,浓缩至近干后用甲醇定容.使用液相色谱-串联质谱进行测定,色谱柱为XTerra MS C18柱,流动相为甲醇和0.025 mol/L乙...     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。