实现标准物质量值溯源性的初步探讨

叙述了研究标准物质量值溯源性的必要性，讨论了实现标准物质值溯源性的基本途径及技术难点。指出了量值溯源的关键是对定值方法和分析过程质量保证技术进行系统的研究。     

化学计量研究进展

叙述了化学计量的特点、作用和重要性及其研究内容,探讨了标准物质量值传递系统及实现标准物质量值溯源性的途径,阐述了建立化学测量溯源性的重要性、困难性、复杂性及基本设想和途径,并对化学计量中物质的量“摩尔”进行了简要论述。     

标准物质的作用

标准物质作为具有准确量值的计量标准 ,是化学计量的重要组成部分和量值传递与溯源的一种重要手段 ,广泛应用于国民经济和社会发展的各个方面 .其主要作用在于 :1　保存和传递特性量值 ,建立测量溯源性　　标准物质是特性量值准确、均匀性和稳定性良好的计量标准 ,具有在时间上保持特性量值 ,在空间上传递量值的功能 .通过使用标准物质 ,可以使实际测量结果获得量值溯源性 .2　保证测量结果的一致性、可比性通过校准测量仪器 ,评价测量过程 ,由标准物质将测量结果溯源到国际单位 (ＳＩ)制 ,保证测量结果的一致性、可比性 ,从而达到量值统一 …     

化学计量研究进展

叙述了化学计量的特点、作用和重要性及其及研究内容，探讨了标准物质量值传递系统及实现标准物质值溯源性的途径，阐述了建立化学测量溯源性的重要性、困难性、复杂性及基本设想和途径，并对化学计量中物质的量“摩尔”进行了简要论述。     

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.     

血清雌二醇标准物质的研制

介绍高浓度血清雌二醇标准物质的研制。采集的全血不加任何添加剂和抗凝剂,离心分离出血清,分装。采用同位素稀释–液相色谱串联质谱法(ID–LC–MS/MS)对高浓度血清雌二醇标准物质进行定值及均匀性和稳定性检验,对定值不确定度进行了评定。结果表明,高浓度血清雌二醇标准物质定值结果为3.06 ng/g,扩展不确定度为0.08 ng/g(k=2),均匀性和稳定性符合国家标准物质技术要求。采用IFCC RELA比对样品和欧洲标准局标准物质血清17β-雌二醇标准物质对定值方法进行确认,测量结果的标准偏差在该标准物质量值的不确定度范围内。研制的标准物质量值经过日本计量院验证,测量结果为(3.03±0.1)ng/g。该标准物质的量值具有溯源性和准确性。     

临床检验量值溯源及其标准物质的研究现状

介绍临床检验量值溯源及标准物质在临床检验领域的重要性与必要性,比较了国内外临床检验用标准物质及临床参考系统的研究现状。建议国家应投入资金,研制更多的高等级临床用标准物质,建立较完整的临床检验溯源体系,提高国际互认能力并降低重复测量费用。     

标准物质的溯源性

1 前言 随着科学技术的发展,有关标准物质的国际活动日趋增多。通商贸易问题和地球环保问题是国际上共同关心的重要问题,为确保对产品质量和环境污染评价等基础工作的计量测试的可靠性,有必要研制具有统一量值的标准物质。特别是已确定特性量值并具有溯源性的标准物质在国际上变得越来越重要。笔者对日本的国家级标准物质,特别是环境计     

化学测量溯源性的探讨

结合化学测量的特点,探讨了实现化学测量量值溯源性的若干问题,主要有实现化学测量量值溯源性的由来、现有的技术基础、溯源性的基本设想及相关的几个问题。     

加湿气体标准物质水含量分析

利用称量法、饱和蒸气压法、流量法3种不同原理的方法分析加湿气体标准物质中加湿量(水分的变化量),测定结果分别为4.66,4.68,4.70 g。依据3种方法的测量模型计算得到3个湿度量值的标准不确定度分别为0.016,0.025,0.666 g。为加湿后气体湿度值的量值溯源提供了3种可靠的方法,为加湿气体标准物质的制备和水含量溯源提供了新思路。     

Traceable property values of in-house reference materials

The traceability of in-house reference materials (IHRM) is discussed. It is shown that a systematic error in results of a measured value, specific to a measurement method or to a laboratory developing an IHRM, can be overcome if a comparative approach to IHRM characterization is used. A traceability chain of the value carried by the IHRM to the value carried by the reference material with higher metrological status and sufficiently similar matrix (for example, a certified reference material – CRM according to ISO Guide 30) is helpful in such a case. The chain is realized when the IHRM samples are analysed simultaneously with the CRM samples under the same conditions. This and other traceability chains necessary for the IHRM development are examined as the measurement information sources.     

Preparation and certification of creatinine and urea reference materials with certified purity as a traceability source in clinical chemical measurements

Purity certified reference materials (CRMs) are playing a key role in metrological traceability, because they form the basis for many traceability chains in chemistry. Recently, the National Metrology Institute of Japan (NMIJ) has developed two purity CRMs for creatinine (NMIJ CRM 6005-a) and urea (NMIJ CRM 6006-a), because the concentrations of these two compounds are frequently measured in clinical laboratories for monitoring the renal functions. In the certification of purity CRMs, it is essential that the materials have been thoroughly characterized for purity, and the purity should preferably be determined directly by a primary method of measurements. In the development of these two CRMs, we used the purified materials as candidates. The certified values were assigned based on the results of two different methods; acidimetric titration and nitrogen determination by the Kjeldahl method. Since both methods cannot distinguish some impurities from the target compounds, major impurities in the candidate materials were also identified, quantified, and subtracted. These CRMs can provide a traceability link between routine clinical methods and SI units. Presented at BERM-11, October 2007, Tsukuba, Japan.     

Extended traceability of pH: an evaluation of the role of Pitzer's equations

The 2002 IUPAC recommendation on pH (provisional) has taken its own philosophy to provide a basis for comparable and traceable assignment of a value, from a measurement, to the quantity pH. Whereas the substituted 1983 IUPAC recommendation relied heavily on precisely prescribed experimental techniques and procedures, the current recommendation defines a hierarchical relationship between references for comparison (primary and secondary standards) and objective criteria on the comparison of measurements with these standards. The recommendation aims at a traceability chain from the national metrological institution (NMI) level down to field and laboratory measurements. Currently, however, the traceability chain is developed to the level of certified reference materials (CRM), namely the above mentioned primary and secondary standards. To complete the traceability chain, several theoretical and practical aspects have to be pondered. In part, the methods for comparative assessment of different options have yet to be developed. As an illustrating example of the complexity of issues to be considered in a further extension of the traceability chain is estimation of the doubt associated with Pitzer coefficients. The Pitzer equations for activity coefficient modelling are explicitly mentioned in the 2002 IUPAC recommendation on pH (provisional) as enabling possible improvement in the ionic strength extrapolations to zero ionic strength. An assessment of uncertainty of ternary Pitzer coefficients is given for the first time.     

k0-NAA, a valuable tool for reference-material producers.

The main concern of producers of certified reference materials (CRM) is the preparation of high-quality products with demonstrated homogeneity and stability, combined with a well established set of certified characteristics. CRM producers must, furthermore, comply with other constraints imposed by the ISO Guide 34: production processes, production control, and certification analyses should be performed by expert laboratories, using validated protocols documented in their respective quality assurance manuals; laboratory mean values and the corresponding "expanded" uncertainties, must be used for the determination of the certified values, as recommended by the ISO Guide to the Expression of Uncertainties in Measurements (GUM); and when possible, traceability of the certified value to the SI units, using appropriately validated and/or primary methods, must be ensured. k0-NAA, i.e. neutron activation analysis with k0 standardization, is one of the analytical techniques implemented at the Reference Material Unit of IRMM; it meets the first two requirements.     

甲基苯丙胺标准物质的定值与不确定度分析

为了建立法庭科学毒品检测量值溯源体系,研制了甲基苯丙胺纯度标准物质。通过红外光谱、质谱法对甲基苯丙胺样品进行定性分析,优化并建立了高效液相色谱(HPLC)、差示扫描量热法(DSC)两种定值分析方法。采用热重分析法和电感耦合等离子体质谱法测定水分和无机离子的含量。通过均匀性与稳定性检验结果表明,甲基苯丙胺标准物质的均匀性良好,稳定性至少1年,同时对其进行了不确定度评定。研制的甲基苯丙胺标准物质的纯度为99.8%,扩展不确定度为0.2%(k=2)。     

Purity determination and uncertainty evaluation of theophylline by mass balance method, high performance liquid chromatography and differential scanning calorimetry

Purity determination of pure organic substance is essential for the establishment of traceability to SI units. A mass balance method was employed to determine the purity of theophylline certified reference materials (CRM), compared with high performance liquid chromatography (HPLC) and differential scanning calorimetry (DSC). In the approach of the mass balance, the impurities were identified by ion trap time-of-flight mass spectrometer (IT-TOF-MS) and quantified by HPLC. The purity of theophylline CRM determined by mass balance method was 99.82% with an extended uncertainty of 0.1% (k = 2). The uncertainty evaluation of purity demonstrated that the accuracy of the mass balance method is better than that of HPLC and DSC. It indicated that the mass balance is suitable for the CRM and pharmaceutical standards.     

k0-NAA, a valuable tool for reference-material producers

The main concern of producers of certified reference materials (CRM) is the preparation of high-quality products with demonstrated homogeneity and stability, combined with a well established set of certified characteristics. CRM producers must, furthermore, comply with other constraints imposed by the ISO Guide 34: ·*production processes, production control, and certification analyses should be performed by expert laboratories, using validated protocols documented in their respective quality assurance manuals; ·*laboratory mean values and the corresponding “expanded” uncertainties, must be used for the determination of the certified values, as recommended by the ISO Guide to the Expression of Uncertainties in Measurements (GUM); and ·*when possible, traceability of the certified value to the SI units, using appropriately validated and/or primary methods, must be ensured. k₀-NAA, i.e. neutron activation analysis with k₀ standardization, is one of the analytical techniques implemented at the Reference Material Unit of IRMM; it meets the first two requirements.     

Using inductively coupled plasma-mass spectrometry for calibration transfer between environmental CRMs

Multielement analyses of environmental reference materials have been performed using existing certified reference materials (CRMs) as calibration standards for inductively coupled plasma-mass spectrometry. The analyses have been performed using a high-performance methodology that results in comparison measurement uncertainties that are significantly less than the uncertainties of the certified values of the calibration CRM. Consequently, the determined values have uncertainties that are very nearly equivalent to the uncertainties of the calibration CRM. Several uses of this calibration transfer are proposed, including, re-certification measurements of replacement CRMs, establishing traceability of one CRM to another, and demonstrating the equivalence of two CRMs. RM 8704, a river sediment, was analyzed using SRM 2704, Buffalo River Sediment, as the calibration standard. SRM 1632c, Trace Elements in Bituminous Coal, which is a replacement for SRM 1632b, was analyzed using SRM 1632b as the standard. SRM 1635, Trace Elements in Subbituminous Coal, was also analyzed using SRM 1632b as the standard.