标准物质量值的溯源性与基准物质的选用

提出了标准物质量值溯源性就是量值传递的不确定性的观点。讨论了标准物质量值溯源性与选用基准物质不确定度的关系。 2 0世纪 90年代以前 ,研制的钢铁标准物质 (或标样 )的量值的溯源性 ,即使当时定值分析使用了基准试剂或光谱纯试剂作为基准 ,它们的溯源性也是良好的     

标准物质特性统计检验及量值不确定度评定

标准物质是实验室用于保证检测数据准确性,实现量值溯源的重要材料或物质。然而很多实验室仅仅局限于简单购买使用成品标准物质,对标准物质概念、特性及定值过程中不确定度评定却不甚了解。针对日常工作遇到的困惑,本文简单介绍了均匀性、稳定性检验方法及特性量值的不确定度评定方法,以期对实验室工作人员系统理解标准物质含义,不断提高实验室的检测技术有一定帮助。     

标称值1μm粒度标准物质的研制

为了完善我国粒度测量溯源及传递体系,满足粒度仪检定校准需求,本文中采用分散聚合的方法制备得到了单分散交联聚苯乙烯标准粒子,所得到的标准粒子球形度好、粒径分布标准偏差为1.5%。利用扫描电子显微镜和图像分析系统对其进行了定值研究,结果表明,该粒度标准物质的量值为1.28μm,定值不确定度为0.9%。     

宽分布激光衍射用固体颗粒度标准物质的研制

研究制备出了宽分布激光衍射用固体颗粒度标准物质,填补了国内宽分布固体颗粒度标准物质的空白。采用高分辨力的扫描电子显微镜(SEM)绝对测量法对标准物质进行定值,标准值可溯源至国家长度基准。定值结果为D₅₀=41.5μm,扩展不确定度为1.76%(k=2)。采用单因素方差分析法和t检验法检验了样品的均匀性和稳定性。定值过程和均匀性、稳定性都符合国家级标准物质的要求。     

颗粒数量浓度标准物质的研制

研制粒径标称值分别为5、10、25μm的颗粒数量浓度标准物质,对商品化的交联聚苯乙烯颗粒样品进行筛分和稳定性考察,采用可溯源至长度标准的方法对粒度标准物质的数量平均粒径进行准确定值,采用光学显微镜法对颗粒数量浓度进行准确定值,并对定值过程中的不确定度进行分析计算。结果表明,所研制的标准物质满足国家标准物质的技术要求,并已成功申报国家标准物质。     

微米级固体颗粒度标准物质系列的研制

介绍了微米级玻璃微珠颗粒度标准物质系列SB040102～SB040109的研制方法,得到粒度分布范围5～95μm不同量值共8个级别的颗粒度标准物质.通过研究与验证,建立了一套符合NIST要求的、具有量值溯源性的颗粒度标准物质的定值方法;提出了颗粒度标准物质性能评价的参数与方法.数据分析表明,研制的系列粒度标准物质与国际先进的粒度标准物质相比,在球形度、粒度分布的单分散性和正态性3方面均达到了先进水平.该项技术对于纳米级颗粒度标准物质的开发与研制,同样具有借鉴意义.     

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;     

GBW(E)100674乙腈中展青霉素溶液标准物质的研制

本课题研制了乙腈中展青霉素的溶液标准物质1种,并已成功申报为国家二级标准物质(GBW(E)100674)。该溶液标准物质以展青霉素纯度国家二级标准物质(GBW(E)100673)为原料,采用重量容量法配制。依据JJF1343-2012《标准物质定值的通用原则及统计学原理》的要求,本研究采用液相色谱法对乙腈中展青霉素溶液标准物质进行均匀性、短期稳定性和长期稳定性的评价。定值不确定度包含原料纯度、溶液配制、均匀性、短期稳定性和长期稳定性五个方面引入的不确定度。最终,该溶液标准物质GBW(E)100674的定值结果为100μg/m L,不确定度为2%。本研究研制展青霉素溶液标准物质的量值具有溯源性和准确性,可以支持国家食品安全检测的需要。     

渗透配气法痕量苯标准气体的研制

文章对渗透配气法制备的标准气体进行了定值研究,并使用固相微萃取—气相色谱联用法对定值结果进行了验证。讨论了定值的原理与方法,并根据定值结果对测量结果不确定度进行了分析。实验表明,采用渗透配气法可制备出nmol/mol量级的苯标准物质,不确定度为6.4%。定值结果溯源链完整,不确定度来源明确。     

比表面积标准物质的定值和不确定度的评定

标准物质的定值就是赋予标准物质特性量值的过程,标准物质作为计量器具的一种,它能复现、保存和传递量值,保证在不同时间和空间下量值的可比性和一致性。对于比表面积标准物质,目前国内外还无法进行绝对方法测量。现阶段,国内外比表面积标准物质的定值过程均采用多家实验室协同定值的方法。本文以国家纳米科学中心研制的纳米级氧化铝比表面积标准物质为实例,对比表面积标准物质的定值过程以及不确定度评定进行了详细介绍。     

系列液体和固体水分标准物质的研制

针对水分检测领域对标准物质的需要,研制了系列水分标准物质,包括4种液体水分标准物质,量值覆盖范围为0.139~47.6 mg/g,不确定度范围为0.012~1.1 mg/g;还包括3种含结晶水化合物水分标准物质,量值覆盖范围为50.7~156.3 mg/g,不确定度范围为0.6~1.3 mg/g,以及3种混合物水分标准物质,量值覆盖范围为0.142~9.90 mg/g,不确定度范围为0.013~0.20 mg/g。该系列液体和固体水分标准物质,适用于卡尔·费休库仑法和容量法水分仪的校准和检定,以及水分测量方法的验证,能够保障我国水分检测的量值准确和等效一致。     

碳黑比表面积标准物质的研制

选择商品化的碳黑作为比表面积标准物质候选材料,利用交叉缩分的方法对碳黑样品进行分装。经均匀性、稳定性(18个月)检验,碳黑标准物质样品具有良好的均匀性和稳定性。按照国际公认的氮气物理吸附BET方法,联合测量能力经确认过的8家实验室对碳黑标准物质样品进行定值(104.6、29.9、8.96 m2/g)。与国内外同类标准物质比较表明:研制的3种碳黑比表面积标准物质的相对不确定度(2.1%、2.3%和3.2%)达到国际同类标准物质的先进水平。     

Determination of methylmercury and butyltin compounds in marine biota and sediments using microwave-assisted acid extraction,solid-phase microextraction,and gas chromatography with microwave-induced plasma atomic emission spectrometric detection

A method is described for the determination of methylmercury and butyltin compounds in marine sediment and tissue using microwave-assisted acid extraction or digestion and solid-phase microextraction (SPME) followed by analysis using gas chromatography with microwave-induced plasma atomic emission spectrometric detection (GC-MIP-AES). Using the SPME-GC-MIP-AES method, enrichment factors for methylmercury and butyltin compounds of 50-100 were achieved, as compared to the typical hexane extraction, and measurements in marine tissue and sediment matrixes were possible at 1-2 microg/kg (methylmercury) and 10-100 ng/kg (butyltins). The SPME-GC-MIP-AES method was validated using several marine sediment and tissue matrix certified reference materials (CRMs) with certified values for methylmercury and butyltin compounds. The SPME-GC-MIP-AES method was used to measure methylmercury in four marine tissue CRMs ranging from oyster tissue at 13.0 +/- 1.0 microg/kg to fish tissue at 397 +/- 13 microg/kg (as Hg dry mass). Results from the SPME-GC-MIP-AES method were used in conjunction with results from other techniques to assign certified values for methylmercury in oyster, mussel, and fish tissue CRMs. Mono-, di-, and tributyltin were measured in three sediment CRMs at concentration levels of (0.08 +/- 0.03)-(0.35 +/- 0.05) mg/kg (as Sn dry mass).     

苯系物溶液标准物质的研究

论述了苯系物溶液标准物质的研究工作 ,系统地介绍了标准物质原材料的选择、特性量值的测量方法、标准物质的制备方法、均匀性检验、稳定性考察以及定值测量。对样品的均匀性、测量的分散性及其他因素引入的不确定度分量分析和确定后 ,给出了整个测量过程不确定度的合成结果。对气相色谱法和液相色谱法所得到的实验结果进行了统计分析 ,其均匀性符合F检验和T检验 ,满足标准物质的技术规范。对苯系物溶液标准物质的稳定性进行了 2年的考察 ,证明该标准物质是稳定的 ,浓度值的不确定度为 2 8%。苯系物溶液标准物质已被批准为国家一级标准物质     

六种多环芳烃溶液标准物质的研制

本文介绍了荧蒽、苯并（b)荧蒽、苯并（k)荧蒽、苯并（a)芘、苯并（ghi)Bai和茚并（1,2,3－cd)芘六种环保用多环芳烃甲醇溶液标准物质的定值测定及均匀性和稳定性考察。定值采用美国国家标准研究院（NIST）的SRM2260和SRM1491作为高一级的标准物质进行量值传递,使用高效液相色谱法（HPLC）,测量不确定度约为3％。     

Preparation of National CRMs of Active Compounds from Natural Products

According to the standard of GB/T1500.3-2008 and the guidelines of ISO/REMCO, the preparation of National Certified Reference Materials (CRMs) of active compounds was composed of the following two aspects: preparation and certification. This paper presents an example of the preparation of biochanin A to illustrate the preparation of National CRMs of active compounds from natural products. Firstly, the target compound was extracted and purified from crude materials. Then,its chemical structure was identified by UV spectrum, IR spectrum, ESI-MS, and NMR. The purity of the compound was determined by HPLC with the area normalization method. The certified value assessed by comparing the purity values from six independent qualified laboratories and the value of uncertainty were given. Thermal analysis, residual solvent, homogeneity testing and stability testing was tested in the process.     

Certified reference materials of trace elements in water

Measurement of trace elements is playing a vital role in industries and various sectors of science and technology including semiconductors, food, health and environmental sectors. In most of the cases a small error in measurement can vitiate all the measures taken for quality control and management. Many decisions regarding the suitability of material/products are based on the analysis. To reduce or eliminate the rejection rate of the products, accurate and reliable measurements are needed which can be achieved by the use of certified reference materials (CRMs). Their use in calibration of analytical equipments and validation of test methods ensures high quality in measurements and it provides traceability to the measurement data with national/international measurement systems (SI unit) also. In the present scenario of globalization of economy, use of certified reference materials (CRMs) in measurements is essential for global acceptance of products and test reports. Their use fulfil a mandatory requirement of international quality systems (ISO 9000, ISO/IEC standard 17025) including our national accreditation body, National Accreditation Board for Testing and Calibration Laboratories (NABL), World Trade Organization (WTO) etc. International manufacturers of CRMs are meeting most of the requirement of CRMs of the country. To meet the demand of CRMs indigenously, the National Physical Laboratory, India initiated a national programme on preparation and dissemination of certified reference materials.     

Certification of the reference sample of plutonium dioxide

An algorithm of certification of plutonium dioxide by the coulometric method is described. The results of measuring the mass fraction of Pu in PuO₂, obtained in certifying and confirming measurements in the course of the development of the state standard sample, are given. The mean mass fraction of Pu in the standard sample material and the uncertainty of the certified value are determined. Based on the results obtained and metrological expertise of the documentation in accordance with GOST (State Standard) 8.315–97, the type of plutonium dioxide composition, SS Pl-tot, is approved, included into the state register, and accepted for use in the Russian Federation.     

Development, validation, and application of a method for quantification of methylmercury in biological marine materials using gas chromatography atomic emission detection

A gas chromatographic method was developed for the quantification of alkylmercury species using microwave-induced plasma atomic emission detection (GC-AED). The column conditioning and analyte derivatization required for previous methods were found to be unnecessary for stable, accurate, and sensitive element-specific detection using GC-AED. Chromatographic and detection parameters such as stationary phase type, stationary phase film thickness, GC column dimensions, helium mobile phase column head pressure, detector makeup gas flow rate, and detector reagent gas type and flow rate were found to significantly affect analyte response. The detection limit for the optimized GC-AED conditions was 0.8 pg (0.1 pg/s) of methylmercury chloride (as mercury). A solid-liquid extraction procedure with preparative gel permeation chromatography cleanup and GC-AED analysis was used to quantify methylmercury in a variety of complex matrix marine materials. The methylmercury quantification method was validated with four marine certified reference materials (CRMs). The method was then applied to 13 standard reference materials, CRMs, and control materials for which no certified reference values for methylmercury have been determined. Four National Institute of Standards and Technology Standard Reference Materials and one control material, which were analyzed using the GC-AED method, were also analyzed by two other laboratories using independent methods to further validate the method.     

Development and evaluation of a reference measurement procedure for the determination of estradiol-17beta in human serum using isotope-dilution liquid chromatography-tandem mass spectrometry

Estradiol is the most potent natural estrogen and is derived from the ovaries. Its concentration in blood is measured to determine ovarian function. A reference measurement procedure for estradiol in serum involving isotope-dilution coupled with liquid chromatography-tandem mass spectrometry (LC/MS/MS) has been developed and critically evaluated. A deuterated estradiol (estradiol-d3) was used as an internal standard. The estradiol and its internal standard were extracted from serum matrix using solid-phase extractions and derivatized with dansyl chloride prior to reversed-phase LC/MS/MS. The accuracy of the measurement was evaluated by a comparison of results of this reference method on lyophilized human serum reference materials for estradiol [Certified Reference Materials (CRMs) 576, 577, and 578] with the certified values determined by gas chromatography/mass spectrometry (GC/MS) reference methods and by a recovery study for the added estradiol. The results of this method for estradiol agreed with the certified values within the uncertainty of the measurements for the three CRMs. The recovery of the added estradiol ranged from 100.7 to 101.8%. This method was applied to the determination of estradiol in frozen serum samples from three individual female donors. Excellent reproducibility was obtained with within-set coefficient of variations (CVs) ranging from 0.6 to 2.2% and between-set CVs ranging from 0.2 to 0.4%. Excellent linearity was also obtained, with correlation coefficients of all linear regression lines (measured intensity ratios vs mass ratios) ranging from 0.998 to 1.000. The detection limit at a signal-to-noise ratio of approximately 3 was 0.6 pg of estradiol (or 1 ng/L, as expressed as a concentration). This well-characterized LC/MS/MS method for serum estradiol, which demonstrates good accuracy and precision, low susceptibility to interferences, and comparability with GC/MS reference methods, qualifies as a reference measurement procedure that can be used to provide an accuracy base to which routine methods for estradiol can be compared and that will serve as a standard of higher order for measurement traceability.