人血清白蛋白纯品含量的同位素稀释质谱方法研究

同时建立了人血清白蛋白(:HSA)纯品含量质量平衡测定方法和同位素稀释质谱测定方法。质量平衡法首先采用高效液相色谱法测定了人血清白蛋白的纯度,然后分别采用卡尔费休法和灼烧残渣法测定其水分和灰分,计算得到HSA的含量为0.861 g/g。在同位素稀释质谱法中,HSA经酸水解后,采用液相色谱-同位素稀释质谱联用法测定了水解液中的Pro、Val和Phe3种氨基酸,进一步计算得出HSA纯品的含量。在最优条件下,HSA含量测定结果为0.853 g/g,相对标准偏差为0.8%,扩展不确定度为0.015 g/g(k=2),检出限和定量限分别为1.37×10~(-5)g/g和4.55×10~(-5)g/g。与质量平衡法测定结果相比,同位素稀释质谱方法测定结果只有0.9%的相对偏差。     

同位素稀释质谱法测定α-淀粉酶的蛋白质含量

利用同位素稀释质谱法测定了盐溶液中α-淀粉酶的蛋白质含量.在含有α-淀粉酶的盐溶液中加入适量的苯丙氨酸标记物后进行酸水解,水解后的氨基酸经过高效液相色谱(HPLC)分离,质谱检测采用选择离子模式,分别监测苯丙氨酸(m/z=166)和标记苯丙氨酸(m/z=174)的离子,根据苯丙氨酸的含量计算α-淀粉酶的蛋白质含量,因此在测定中只需要氨基酸的标准物质就可以保证蛋白质含量测定结果的溯源性.实验中优化了酸水解的时间,采用HPLC-MS和MALDI-TOF质谱证明了淀粉酶已完全水解,并对测定结果的不确定度进行了评估.该方法可以准确测定溶液中蛋白质含量,并可用于蛋白质含量标准物质的定值.     

牛血清白蛋白溶液标准物质定值结果的不确定度评定

一、概述 牛血清白蛋白第V组分（BSA）是牛血清中的一种球蛋白,包含583个氨基酸残基,分子量约为66430,等电点为4.7。牛血清白蛋白广泛应用于生化实验中,也是最常用的蛋白质定量的标准。为了保证我国蛋白质含量测定结果的准确、可比与可溯源,中国计量科学研究院率先采用同位素稀释质谱法和纯度扣除法研制了牛血清白蛋白固体国家一级标准物质,定值结果为（0.963±0.038）g/g。     

重组人白介素-2标准品的表征及同位素稀释质谱法定量测定

人白介素-2(HuIL-2)为免疫增强剂。重组人白介素-2(rHIL-2)是基因重组生物制品,生物活性与天然IL-2相同,含有133个氨基酸残基。为了对白介素-2类药品进行有效的质量控制,文章研制了重组人白介素-2标准品,采用高效液相色谱法对白介素-2的纯度进行表征,采用飞行时间质谱对相对分子质量进行测定,采用飞行时间质谱和高分辨质谱方法对肽图、二硫键进行表征,同时利用氨基酸同位素稀释串联质谱方法对标准品含量进行了准确测定。结果表明,重组人白介素-2溶液标准品纯度为99.1%,实测相对分子质量为15415.78 Da,与理论分子量15415.82 Da一致,二硫键链接方式为Cys58-Cys105,氨基酸覆盖率为100%。同位素稀释串联质谱定量测定标准品含量的结果为0.0947 mg/g。     

甲醇中萘溶液标准物质的研制

以色谱纯甲醇和高纯物质萘为原料,采用重量-容量法准确制备特性量值为1.00×10-4 g/mL的甲醇中萘溶液标准物质.研制的标准物质通过了均匀性检验和稳定性考察,并对定值结果进行了不确定度评定.该溶液标准物质已被批准为国家二级标准物质(编号GBW(E)130395),相对扩展不确定度为3％(k=2),可用于液相色谱仪的检定.     

鱼肉中甲基汞成分标准物质的国际合作研究

甲基汞对人的中枢神经系统有很强的伤害性.海产鱼类是人类饮食中主要的甲基汞来源,对其检测需要用到标准物质进行质量控制和量值溯源.中国计量科学研究院制备了一种新的鱼肉标准物质,并与南开大学化学系、日本国家计量研究院共同合作研究,使用同位素稀释-液相-电感耦合等离子体质谱联用方法(ID-LC-ICPMS)、同位素稀释-气相-电感耦合等离子体质谱联用方法(ID-GC-ICPMS)和高效液相色谱-冷蒸气原子荧光光谱法(HPLC-CVAFS)等多种方法对其中甲基汞成分进行定值.     

UPLC-Q-TOF快速测定常见氨基酸含量

结合外标法或同位素稀释质谱法,建立UPLC-Q-TOF快速定量氨基酸分析方法。在无离子对试剂及衍生化情况下,实现对样品中氨基酸的快速测定。采用外标法测定时,14种常见氨基酸在其相应线性范围内,r2为0.953~0.999,LOD为0.001~0.080 mg/g,CV为1.4%~9.8%;采用Q-TOF外标法定量时,CV为1.5%~8.0%,误差为-9.1%~40%;采用同位素稀释质谱法测定各氨基酸浓度时,CV为1.4%~3.8%,误差为-3.4%~3.7%。本方法可在2min之内完成14种氨基酸的分离和定量,大大缩短分析时间。同时由于采用高分辨的飞行时间质谱,避免检测时离子间的相互干扰,提高测定结果的准确性,可用于蛋白质标准物质均匀性、稳定性检验及定量。     

计量基础研究及科技创新——《四川省计量发展规划(2014～2020)》宣贯内容连载之九

<正>生物安全量值溯源关键技术研究(1)核酸、蛋白质测量方法研究核酸同位素稀释质谱法(不确定度3.6%);蛋白质同位素稀释质谱法(不确定度2.6%);含硫基蛋白质毒素的LC-ICP-SFMS定值方法(不确定度0.8%);病原微生物核酸水解-碱基测量的同位素稀释质谱法(不确定度5%)。(2)转基因植物和微生物检测标准物质研究转基因核酸质粒分子标准物质;     

同位素稀释质谱法测定茶叶中的铜

采用同位素稀释质谱法(ID-ICP-MS)测定了茶叶中的Cu.将65Cu同位素稀释剂与样品混合,以HNO3-H2O2体系对混合样品进行微波消解,通过测定63Cu/65Cu丰度比计算样品中的Cu含量,并对测定结果的不确定度进行了评定.测定结果与NIST标准物质符合的很好,该方法较传统方法准确度高,适合标准物质的定值.     

空气中一氧化碳气体标准物质的研制

采用一氧化碳纯度标准物质、高纯氮气和高纯氧气,以称重法制备了浓度为(10. 0～10. 0×10~2)×10~(-6)mol/mol的空气中一氧化碳气体标准物质。运用气相色谱仪测定了高纯氮气、高纯氧气中一氧化碳的空白含量,并基于一氧化碳红外气体分析仪对研制的标准物质进行了压力均匀性和时间稳定性检验。运用方差分析可得均匀性引入的相对标准不确定度为0. 42%,运用直线拟合分析稳定性引入的相对标准不确定度为0. 44%。结果表明,研制的空气中一氧化碳气体标准物质具备很好的均匀性和稳定性,标准值为(10. 0～10. 0×10~2)×10~(-6)mol/mol(Urel=2%,k=2),可用于测量仪器的校准、测量过程质量控制及分析方法确认和评价。     

科氏力质量流量计质量流量参量的温度系数

科氏力质量流量计的质量流量和密度参量的温度系数 ,与其材料的线膨胀系数和杨氏模量的温度系数有关 ,并可由谐振频率的温度系数求出。当采用 1Cr18Ni9Ti时 ,在 - 10℃～ 6 0℃的温度范围内 ,质量流量参数的温度系数是 - 4 2 4× 10 - 4 ℃ ,密度参数的温度系数是 4 2 4× 10 - 4 ℃。     

Quadrupole-based glow discharge mass spectrometer: Design and results compared to secondary ion mass spectrometry analyses

A design of quadrupole-based glow discharge mass spectrometer is briefly presented. A glow discharge occurs when a DC voltage (up to 3 kV) is applied between two electrodes in a cell filled with Ar at ∼1 hPa pressure. In this configuration, the sample acts as the cathode, and its surface (∼12 mm²) is sputtered by impacting Ar ions. The sputtered neutral atoms are ionised downstream in the plasma, and are extracted through a diaphragm to an energy filter and quadrupole spectrometer (6 mm rods) in high vacuum. The processes of sputtering and ionisation are separated, therefore reducing matrix effects.Preliminary results of elemental analysis of stainless steel, chromium-vanadium steel, Al-Mg-Cu and Armco alloys are presented. These results are compared to secondary ion mass spectrometry (SIMS) results obtained for the same set of samples using a 5 keV Ar⁺ ion beam and a quadrupole mass analyser (16 mm rods). The glow discharge mass spectrometry (GDMS) results allowed us to find SIMS relative sensitivity factors (RSF) for the analysed materials. Simple design and quick analysis time makes the new GDMS analyser an attractive tool in material technology.     

Vibration analyses of a portal frame under the action of a moving distributed mass using moving mass element

Four kinds of moving mass elements, 1st‐node, 2nd‐node, full and short‐range mass elements, are presented, where the 1st‐node (or 2nd‐node) mass element refers to that with mass distributed from the first node (or second node) to the arbitrary position of a two‐node beam element, the full mass element is the special case of the 1st‐node (or 2nd‐node) mass element with mass distributed over the full length of the beam element, while the short‐range mass element is the case with its location arbitrary on a beam element. If the total range of a distributed mass is denoted by R and the length of each beam element is denoted by ??, then, for the case of R???, one may model the distributed mass on the beam using the combination of the 1st‐node, 2nd‐node and full mass elements, while for the case of R<??, one may model the distributed mass using the short‐range mass element. It has been found that the effects of the vertical (?) and horizontal (x?) inertia forces, Coriolis force and centrifugal force induced by the moving distributed mass can be easily taken into the formulations by means of the last concept. To illustrate the application of the presented theory, the dynamic analysis of a pinned–pinned beam and that of a portal frame under the action of a moving uniformly distributed mass are performed by means of the finite element method and the Newmark integration method. Numerical results show that some pertinent factors, such as Coriolis force, centrifugal force, acceleration, velocity and total range of the moving distributed mass, have significant influences on the vertical (?) and horizontal (x?) response of a structure. Copyright © 2005 John Wiley & Sons, Ltd.     

颗粒调谐质量阻尼器减震控制的数值模拟

提出一种颗粒调谐质量阻尼器,即通过摆绳将颗粒阻尼器悬挂于主体结构上,将目前广泛应用的调谐质量阻尼器与减震效能优越的颗粒阻尼器结合起来,以扩大减振频带,增加减振鲁棒性。基于一定的等效原则将多颗粒阻尼器等效为单颗粒阻尼器,提出一种近似的颗粒调谐质量阻尼器数值模拟方法,并介绍了系统参数的取值方法。进行了附加颗粒调谐质量阻尼器的单自由度结构实际地震输入下的振动台试验,通过对比试验结果与数值模拟结果,发现两者吻合较好,说明该简化方法可以较好地模拟颗粒调谐质量阻尼器的减震控制效果。     

Structured graphene devices for mass transport

The reversible atomic-mass transport along graphene devices has been achieved. The motion of Al and Au in the form of atoms or clusters is driven by applying an electric field between the metal electrodes that contact the graphene sheet. It is shown that Al moves in the direction of the applied electric field whereas Au tends to diffuse in all directions. The control of the motion of Al is further demonstrated by achieving a 90° turn, using a graphene device patterned in a crossroads configuration. The controlled motion of Al is attributed to the charge transfer from Al onto the graphene so that the Al is effectively charged and can be accelerated by the applied electric field. To get further insight into the actuation mechanism, theoretical simulations of individual Al and Au impurities on a perfect graphene sheet were performed. The direct (electrostatic) force was found to be ～1 pN and dominant over the wind force. These findings hold promise for practical use in future mass transport in complex circuits.     

大试剂比条件下液膜传质机理

提出了确定液膜过程传质机理的新方法，其要点为：在膜相中增加载体浓度，就会提高溶质在膜相的分配比，一般也会提高液膜中传质速度．比较分配比提高的倍数和传质速度提高的倍数，可判断该过程的速控步骤：如这两个倍数相等，即速度和分配比成正比，则为膜相控制；如分配比增大而传质速度不变，则为外水相扩散控制；如速度增加倍数小于分配比增加倍数，则为混合控制．在混合扩散控制时还给出了估算不同过程扩散的相对阻力，并对我们过去研究过的体系作了验证，得到一些有意思的结果．还对ｌｎ（Ｃ０／Ｃ）～ｔ有无直线关系作了探讨     

分压力质谱计的校准

分压力质谱计的校准是一个没有完全解决的难题。本文只是从普遍的原则介绍了校准分压力质谱计时应注意的问题，如分压力质谱计的调整、校准前的检查等。还对最新的四种分压力质谱计推荐校准方法及相应的校准装置做了描述。最后对兰州物理研究所研制的分压力质谱计校准装置进行了简要介绍，供从事分压力质谱计校准研究的工作者参考。     

Multicomponent aerosol mass efficiency with various mixture types for polydispersed aerosol

Based on the filter-sampled chemical composition data the seasonal variation of the optical properties of polydispersed aerosols, extinction, scattering, and absorption coefficient, are estimated for various types of aerosol mixtures. The mixtures considered in this study are the internal mixture, elemental carbon (EC)/non-EC external mixture, and fully external mixture. This study also evaluated the sensitivity of the aerosol optical properties for different size distributions. The results show that the extinction coefficient can be mostly accounted for scattering and generally shows a good agreement with each mixture type in this case study. However, the absorption coefficient shows a different tendency for internal and external mixtures. This study also shows that the aerosol optical properties vary as a function of particle diameter at the same composition and mass concentration. This means that mass extinction, scattering, and absorption efficiencies, which were considered as constants in general, should be reassessed and more specifically described as a function of particle size.     

飞行时间质谱——光离子成像技术的设计

简述了飞行时问质谱——光离子成像技术的原理和设计。详细介绍了国内相关设备的技术特点和系统结构。     

多级非线性双质量飞轮参数设计和优化

在长弧形弹簧双质量飞轮结构的基础上,针对其核心部件——减振弹性结构形式进行创新设计,使得减振器的刚度由单级刚度变成了三级刚度。讨论了多级非线性双质量飞轮的各个参数的选取原则。针对国产某轿车的动力传动系统建立了离散化的整车动力传动系分析模型。对传动系统在行驶工况下和怠速工况下的固有特性进行分析,预测和评价多级非线性双质量飞轮的扭振控制效果。最后基于ADAMS对多级双质量飞轮的减振性能进行仿真和优化分析,得到了设计所需参数的最优值。