有机纯度标准物质定值技术研究进展

有机标准物质作为参考标准广泛应用于色谱分析领域。有机标准物质化学纯度定值技术是赋予标准物质准确量值的关键。纯度定值技术包括直接测量主组分的方法和扣除杂质的方法。直接测量主组分的方法主要有气相色谱法(GC)、液相色谱法(LC)、定量核磁法(qNMR)、元素分析法和滴定法(重量滴定和容量滴定)。扣除杂质的方法要测量所有可以检测到的杂质组分,然后将其扣除来计算主成分的含量。典型的扣除杂质的方法是凝固点下降法和差示扫描量热法(DSC),并结合水分测量、残留溶剂测量和无机杂质测量进行分析。该文总结了有机标准物质化学纯度的多种定值技术(2000～2012),比较了多种定值技术的优缺点与局限性,并对有机标准物质化学纯度定值技术的发展进行了展望。     

熔点标准物质的定值

介绍凝固点下降薄层比较法测量熔点标准物质熔点的测量装置的构成与工作原理。用该装置对5种标准物质的凝固点或熔点进行了测量,给出了定值结果和不确定度。     

液体高纯有机物纯度的准确测量

介绍用凝固点下降薄层比较法测量五种高纯液体有机物的纯度,并进行了不确定度分析,测量结果准确可靠。     

LGC五种熔点标准物质的定值

介绍英国政府化学家研究所（LGC）研制的五种熔点标准物质的熔点和凝固点的定值方法、定值结果及不确定度的估计。     

熔点和凝固点的准确测量

介绍了英国政府化学家研究所(IGC)和兵总第204所样品的熔点和凝固点的准确测量方法,熔点和凝固点的测量结果,并进行了讨论。     

葫芦巴碱标准物质的研制

研制葫芦巴碱标准物质。分别采用质量平衡法和定量核磁法两种不同原理方法对葫芦巴碱标准物质的纯度进行定值。利用高效液相色谱法对葫芦巴碱标准物质的均匀性和稳定性进行考察。对葫芦巴碱标准物质纯度定值结果的不确定度进行评定。结果表明,葫芦巴碱标准物质的纯度定值结果为99.31%,扩展不确定度为0.4%(k=2)。研制的葫芦巴碱标准物质量值准确,均匀性和稳定性符合二级标准物质技术要求。     

熔点8和凝固点的准确测量

介绍了英国政府化学研究所（ＬＧＣ）和兵总第２０４所样品的熔点和凝固点的准确测量方法，熔点和凝固点的测量结果，并进行了讨论。     

浅谈蛋白质含量量值溯源传递体系的构建

简述了蛋白质含量测定结果溯源到SI单位的重要性,结合中国计量科学研究院开展的工作及当前国际蛋白质计量发展的趋势,阐述了实现蛋白质含量测定结果溯源到SI单位的两种方案,方案中蛋白质标准物质的定值结果可以通过同位素稀释质谱法、滴定法、凝固点下降法等权威计量方法最终与SI单位连接,因此保证了蛋白质标准物质定值结果的准确和可溯源.以蛋白质标准物质作为量值的载体,可实现蛋白质含量量值在应用领域的传递,从而构建起蛋白质含量量值溯源和传递体系.     

氢化可的松纯度标准物质的研制

介绍纯度标准物质氢化可的松的研制方法.采用高效液相色谱法对该标准物质进行了定值及均匀性、稳定性检验.该标准物质定值结果为99.5%,扩展不确定度为0.2%,其均匀性和稳定性检验结果表明,该标准物质符合国家一级标准物质的技术要求.     

标准物质标准值标准偏差应用探讨

《一级标准物质技术规范》和《军用标准物质管理办法》及其实施细则规定 ,标准物质特性量定值有以下三种方式 :( 1 )用高准确度的绝对或权威测量方法定值 ;( 2 )用两种以上不同原理的已知准确度的可靠方法定值 ;( 3)多个实验室合作定值。在我国标准物质研制的实际工作中 ,大多采用后两种方式相结合的办法对标准物质特性量进行定值 ,即在策划定值方案时 ,既考虑采用两种以上不同原理的已知准确度的可靠方法 ,又由多个实验室进行合作定值。当采用多种方法和 /或多个实验室对标准物质特性量定值时 ,对多组观测值的数理统计处理结果表明 ,其标准…     

Certified calibration solution reference material for the determination of perfluorooctane sulfonate from the National Metrology Institute of Japan (NMIJ)

A new calibration solution reference material for the determination of perfluorooctane sulfonate anion (PFOS) and its salts has been issued as a certified reference material (CRM) by the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). The purity amount-of-substance fraction of raw material potassium perfluorooctane sulfonate (K-PFOS) was evaluated based on the results obtained using the freezing point depression method, and the purity mass fraction of the raw material was calculated using the average molar mass of impurities, the molar mass of K-PFOS, and the purity amount-of-substance fraction. The certified concentration of this CRM was obtained by multiplying the dilution ratio of the raw material in a prepared solution (methanol) determined from the gravimetric blending method by the purity of the raw material. The preparation concentration of K-PFOS as a certified value of NMIJ CRM 4220-a was determined to be 9.93?mg?kg^?1. In addition, the standard uncertainty of the certified value was evaluated from the purity evaluation as well as from sample inhomogeneity, instability, and preparation variation obtained from LC/MS measurements of different gravimetrically prepared solutions of the NMIJ CRM. Consequently, the expanded uncertainty was estimated to be 0.15?mg?kg^?1 with a coverage factor k?=?2 corresponding to the half-width of estimated confidence interval of approximately 95%.     

隐身材料微波隐身特性评估方法

列举了隐身材料微波电磁参数、反射率、目标雷达散射截面(RCS)的测试方法和相关标准,重点介绍了探头法、谐振腔法、传输反射法、自由空间等电磁参数测量方法及弓形法、远场法等反射率测试方法的基本原理和测试装置,分析了各种方法的特点和适用范围。     

半导体凝固点测定仪的研制及其应用

为了配合物理化学实验“凝固点降级法测定萘的摩尔质量”,研制出半导体制冷凝固点测定仪,实现了凝固点测定和摩尔质量计算的自动化,解决了老式实验装置存在的问题。通过对环己烷凝固点和萘摩尔质量的测定,验证了该仪器的可靠性,同时还探讨了搅拌速率和冷阱的温度变化对凝固点测定值的影响。     

蛋白质及多肽C端测序的研究进展

C端序列是蛋白质和多肽的重要结构与功能部位,对蛋白质的生物功能甚至起决定性作用。另外,C端剪切也是蛋白质重要的翻译后修饰之一。随着蛋白质组学研究的不断深入,蛋白质C端测序对其功能研究将发挥越来越重要的作用。一些新的蛋白质C端测序方法已建立,提高了灵敏度和重复性,能够在蛋白质组水平应用。本文较系统地介绍了蛋白质C端测序3种方法:羧肽酶法、化学法及串联质谱法的原理、特点、应用及在蛋白质组学研究中的新进展。随着C端测序新方法的不断建立,将在蛋白质组研究中发挥更大的作用。     

强电解质稀溶液的依数性公式导出及实验验证

讨论了强电解质稀溶液的依数性,即凝固点降低、沸点升高和渗透压。以稀溶液的凝固点降低为例,利用Gibbs-Duhem公式,推导了强电解质稀溶液的凝固点降低公式,并利用Na Cl水溶液的凝固点降低实验验证了该公式的正确性。     

The determination of the gamma isomer content of hexachlorcyclohexane dipwashes

The gamma BHC content of dipwashes has been deterimined satisfactorily by a cryoscopic method. The dipwash is treated with chromic acid to precipitate the total BHC and to destroy much of the organic impurity. Portions of the isolated impure BHC arc dissolved in both benzene and pure gamma BHC. By measurement of the resultant freezing point depression of the solvents, the proportion of gamma isomer in tho original sample can be calculated. The principle of the method should be applicable to other systems where the determination of one component in a multi-component mixture is required.     

Current activities of ISO TC229/WG2 on purity evaluation and quality assurance standards for carbon nanotubes

The current standardization activities of ISO (International Organization for Standardization) TC229 on “Nanotechnology” are introduced with focus on the work of WG2 (Working Group 2) for “measurement and characterization”. Seven project groups of WG2 are actively preparing standard protocols (technical specifications) for characterization of single-wall carbon nanotubes (SWCNTs) by measurement methods such as TEM (transmission electron microscopy), SEM (scanning electron microscopy), EDX (energy-dispersive X-ray analysis), UV–Vis–NIR (ultraviolet-visible-near infrared) absorption spectroscopy, NIR-photoluminescence spectroscopy, EGA (evolved gas analysis)–GC–MS (gas chromatography–mass spectrometry), TGA (thermogravimetric analysis), and Raman spectroscopy; this work is described. The features of purity evaluation of SWCNTs by these methods are also briefly described and compared. Also described are two project groups of WG2 that are preparing standard protocols for characterization of multiwall CNTs (MWCNTs), aiming at the purity control by measurement of moisture content, ash content, metallic constituents, volatile content, polyaromatic hydrocarbon content, and carbon materials excluding MWCNTs. Other important properties for characterization of MWCNT, for example disorder, burning property, stacking nature, length, morphology, and inner/outer diameter, etc., are also mentioned. Finally, the importance and urgency of standardization for potential risk assessment of CNTs is briefly described, and current joint activity of ISO TC229 WG2 and WG3 for physicochemical characterization of engineered nanoscale materials for toxicological assessment is introduced.     

An improved test method for characterising touch properties of porous polymeric materials

A new test method and instrument was developed to provide overall evaluation and characterisation of touch properties of porous polymeric materials. The test method and instrument can simulate the dynamic contact process between human skin and porous polymeric materials and obtain the mechanical and physical performance during contact. In the improved test method, a new measurement principle was proposed, and the mechanical device was redesigned, including surface friction measurement components. Most indices were redefined and the grading and classification methods were studied to give a direct overall evaluation of the touch properties for industrial applications. The objective test results and analysis, subjective evaluation method and prediction model of touch properties are also presented. The improved test method provides an objective measurement of thermal-mechanical properties using a single measuring instrument for new product development and quality control of porous polymeric materials.     

Place of DSC purity analysis in pharmaceutical development

DSC purity analysis is based on thermodynamic phase diagrams for substances (purity ≥98%) which undergo a melting point. Impurities which have eutectic behaviour with the analyte are determined together. DSC purity analysis obtained from a single melting event of a 1–2 mg sample is, therefore, extremely attractive for the global assessment of eutectic impurities. The main advantages in early development lie in the very small amount of material necessary and the very fast analysis time. However, the DSC purity analysis cannot replace chromatographic methods which deliver specific individual levels of impurities. Furthermore, a complete validation of a DSC purity method is difficult and time consuming. Despite these limitations, DSC is the best support for the development of chromatographic methods, for purity profile and stability assessment during pharmaceutical development. Parameters of purity determination and validation aspects are discussed. Examples of use in pharmaceutical development are given.