热表面电离同位素稀释质谱法测定IMEP—9国际比对水标样中镁的研究

同位素稀释质谱法 ( IDMS)是微量、痕量元素量值测量的准确方法之一 [1,2 ]。已应用到环保、生化等领域中 ,在痕量、超痕量化学分析中起着重要的作用 [3～ 5] 。欧共体联合研究中心标准物质与测量研究院 ( EC- JRC- IRMM)从 1 988年开始专门组织了国际测量评估计划 ( IMEP)。该计划已实施多次 ,每次都有来自不同国家和地区的 2 0 0多个实验室参加比对测量。IMEP国际比对样品中无机元素的标准值大都采用 IDMS方法测得 [6] 。本实验室应EC- JRC- IRMM的邀请参加了 IMEP- 9国际比对标准样品的定值工作。本工作采用 IDMS对IME…     

同位素稀释热电离质谱法测定人血清中痕量铜和锌

采用热电离同位素稀释质谱法(ID-TIMS)准确测定了欧盟标准物质与测量研究院(EC-JRC-IRMM)组织的国际测量评估计划IMEP-17人血清样品中的痕量铜和锌。由于锌和铜都是易受污染的元素,本工作建立了仅用少量硝酸消解的低流程本底和适于热电离质谱测量的生物基体血清中痕量铜和锌的样品前处理方法;采用适当比例的硅胶和磷酸作为电离增强剂,在热电离质谱(TIMS)测量时获得了较高强度且稳定的铜和锌离子束;血清中痕量铜和锌的测量结果可直接溯源到国际单位mole。2种人血清样品中铜和锌测量结果的不确定度(k=2)分别为0.94%、0.83%和0.49%,测量值被EC-JRC-IRMM采用作为该样品的标准值。     

ICP-MS测定PM2.5中痕量重金属及铅同位素

建立了HNO3-H2O2湿法消解、电感耦合等离子体质谱(ICP-MS)同时测定PM2.5样品中痕量重金属Cr,Ni,Cu,As,Cd,Pb和Pb同位素的方法。通过内标校正克服了基体效应、物理效应和仪器的长短期漂移的干扰。在ICP-MS优化参数下,测定的痕量元素及Pb同位素的标准曲线相关系数均优于0.9997,5种痕量元素的方法检出限在0.01~0.07μg/L之间,4种Pb同位素的方法检出限在0.014~0.07μg/L之间。通过测定滤膜标准物质(GBW(E)080212)和Pb同位素标准物质(NIST981)考察了方法准确性,测定值均在标准值范围内。当Pb质量浓度大于10μg/L时,浓度对Pb同位素比值的测量影响不显著。运用该方法测得厦门市PM2.5中6种痕量重金属元素的RSD小于4.8%,Pb同位素RSD小于0.5%。     

同位素稀释碰撞室多接收电感耦合等离子体质谱测定鱼中痕量硒

采用六极杆碰撞室多接收电感耦合等离子体质谱（MC-ICP-MS）和同位素稀释技术,通过对碰撞气的使用、硒氢的校正、质量偏移的校正、基体效应、样品前处理等方面的研究,建立了鱼肉中痕量硒的同位素稀释电感耦合等离子体质谱（ID-MC-ICP-MS）准确测量方法.进而使用该方法参加了国际计量委员会物质量咨询委员会组织的国家化学计量研究院之间的比对（CCQM-P39.1 ＆ CCQM-K43）,对比对样品鲑鱼中的痕量硒进行了测量,测量结果是7.38±0.22（μmol/kg） ,与该样品的标准值7.32±0.28（μmol/kg） 符合很好,验证了本方法的可靠性和准确性.     

红酒中的~(87)Sr/~(86)Sr同位素比测定

研究了多接收电感耦合等离子体质谱(MC-ICP-MS)测定红酒样品中87Sr/86Sr同位素比的分析方法,并用建立的分离测定方法参加了欧洲参考物质与测量研究所(IRMM)组织的CCQM-P105国际比对,即红酒中87Sr/86Sr同位素比的分析比对.红酒样品经微波消解后,采用Dowex 50W×8树脂分离纯化锶,用MC-ICP-MS精确测定锶组分中的87Sr/86Sr同位素比,同时对测量结果的不确定度进行了分析和评定.     

血清中尿酸和尿素含量测定的超高效液相色谱–单四级杆质谱法国际比对

基于单四极杆质谱建立了血清中尿酸、尿素含量准确测定的同位素稀释超高效液相色谱–质谱方法,并以该方法参加了国际物质量咨询委员会(CCQM)组织的"血清中尿酸尿素含量测定"的K、P国际比对。血清样品用乙腈除去蛋白质,分别采用C18反相柱和电喷雾(ESI)负离子模式检测尿酸、CN正相柱和ESI正离子模式检测尿素,同位素稀释的单点校准法进行定量,用3种标准物质(GBW 09157,GBW 09169,NIST SRM 909c)进行方法验证,测量比对血清样品(Ⅰ,Ⅱ)获得国际等效一致性。该方法操作简单、快速准确,适用于血清中尿酸尿素的定量分析。     

质谱同位素稀释法测定粉煤灰中痕量Eu

以~(151)Eu作稀释剂,质谱同位素稀释法(IDMS)测定了粉煤灰中痕量Eu。通过降低Eu空白获得了较低的检出限。方法检出限为8.7×10~(-10)gEu,精密度为±2%。     

钐同位素丰度的绝对测量

建立了钐同位素丰度高精度的质谱测量法。对样品形态选择、离子转换效率、离子传输效率和离子接收效率进行研究,消除了浓缩同位素测量时强峰拖尾对弱峰的干扰及同量异位素干扰。用已知化学纯度的^152Sm、^154Sm两种浓缩同位素,通过化学计量配制人工合成校正样品,测量质谱计的系统误差校正系数,对用该仪器测量的来自不同地域矿物和试剂样品中钐元素天然同位素的丰度比数据进行校正,准确求得钐同位素的丰度。     

微波消解ICP-MS法测定锂离子电池石墨负极材料中9种痕量元素

建立微波消解–ICP–MS法测定锂离子电池石墨负极材料中Al,Cr,Cu,Fe,K,Na,Ni,Pb,Zn 9种痕量元素含量的方法。采用硝酸–盐酸体系微波消解样品,稀释后用ICP–MS法测定样品消解溶液中9种痕量元素的含量。在优化仪器工作参数后,采用同位素和He模式克服质谱干扰。9种元素的质量浓度与质谱强度具有良好的线性关系,线性相关系数为0.999 1~0.999 8,检出限为0.132~3.700 mg/kg。加标回收率为98.4%~101.0%,测定结果的相对标准偏差为0.3%~3.6%(n=6)。该方法测定结果准确可靠,可用于锂离子电池石墨负极材料中痕量元素的测定。     

浓缩钼同位素的纯化新方法及质量分馏测定

基于三氧化钼易升华的特性,建立了一种纯化浓缩钼同位素试剂的新方法.采用天然丰度掺杂样品Synthetic-Mo对纯化过程中的氧化时间、样品加入量及真空蒸发温度等条件进行了优化.用高分辨等离子体质谱分析了样品中杂质的含量,计算得到纯化后95Mo和98Mo浓缩同位素试剂的纯度分别为99.992%和99.990%.通过多接收器等离子体质谱测定纯化前后样品中钼同位素的组成,δX/95Mo(X=92,94,96,97,98,100)值均在仪器测量精度(0.3‰)范围之内,未观察到明显的质量分馏现象.该方法能够满足校正质谱法对浓缩同位素试剂的要求,对建立高准确度的钼同位素丰度比测量方法具有重要意义.     

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。     

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.

     

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.     

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。