测定血清中Na 含量不确定度的评定

对血清中Na离子含量的测量不确定度进行评定。不确定度的来源主要包括Na离子标准工作液的配制过程、血清样品的定容消化制备、标准曲线拟合、钠离子各分量不确定度的合成等引入的不确定度计算出各分量的不确定度,通过合成得到测量结果的合成不确定度、扩展不确定度及测试结果的报告形式。     

原子吸收光谱法测定血清中Na+含量不确定度的评定

对测量血清中Na+含量的不确定度进行评定。不确定度的来源主要包括血清样品的消化、制备、定容,Na+标准工作液的配制过程、标准曲线拟合等引入的不确定度,计算出各分量的不确定度,通过合成得到测量结果的合成不确定度、扩展不确定度及测试结果的报告形式。     

碘量法测定水中溶解氧含量测量不确定度的评定

分析碘量法测定水中溶解氧含量测量不确定度的影响因素，对测量不确定度各个分量的评定结果表明，测量重复性的不确定度分量最大，其次是样品溶液的体积、滴定溶液的体积和滴定溶液的浓度等不确定度分量，计算得到水中溶解氧含量测定结果的合成不确定度为0．06mg/L，扩展不确定度为0．12mg/L。     

水氯化物的测定不确定度评定方法

根据GB/T 11896-1989《水质氯化物的测定硝酸银滴定法》国标方法对水中氯化物测定的不确定度进行评定。首先对不确定度主要来源进行识别,如测量重复性、标准NaCl的纯度、称量和定容、液体的转移、标准溶液在滴定和标定时滴定管的体积计量、温度等,然后建立数学模型,分别计算各输入量的不确定度分量和相对不确定度分量,合成各相对不确定度分量的方差和合成标准不确定度计算,得到测量结果的最终表示方式。     

ICP-MS法测定高纯铝中杂质不确定度的评定

利用ICP-MS测定高纯铝中杂质。用建立数学模型的方法对结果的不确定度进行评估和计算。对试料的称重、标准溶液的配制、工作曲线的拟合、测量重复性的各分量不确定度进行分析。得到了各分量不确定度和合成不确定度,最终得出更加客观的结果。     

氢化物发生-原子荧光光谱法测定高纯氧化镧中硒、碲的不确定度评定

对高纯氧化镧中硒、碲含量测定过程中的不确定度来源进行了辨别,并在此基础上评定了分析结果的不确定度[1～3]。测量不确定度主要来源于试样称量、标准溶液配制、工作曲线拟合、各种玻璃量器的使用及测量重复性。依据不确定度评定的步骤,分析和计算得到了各分量标准不确定度及合成标准不确定度。     

气相色谱内标法测定皮革中五氯酚残留量不确定度评估

采用气相色谱内标法测定皮革中五氯酚残留量,对整个测量过程的不确定度来源进行了分析,并对不确定度各个分量进行了评估和合成,结果显示,样品重复性测量不确定度分量对总不确定度的贡献最大。当五氯酚测定结果为1.021 mg/kg时,扩展不确定度为0.056 mg/kg。按照相关计量规范要求,给出了五氯酚测量结果不确定的表达式。     

轻质油闭口闪点不确定度的评定

介绍了轻质油品闭口闪点测定过程中检测结果不确定度的评定方法,从测量程序各步骤评定了不确定度的各项来源,对测量过程中的主要不确定度分量进行了合理评定,包括升温速率;温度计的计量性;计算时数字修约等不确定度分量的评定,最后求得闭口闪点检测结果的合成标准不确定度。为实验室在该项检测过程中进一步提高检测数据的准确性作参考。     

脉冲熔融热导法测定钒粉中氮含量的不确定度评定

利用脉冲熔融热导法测定了钒粉中氮含量,并分析了测量过程中产生的不确定度因素,通过各个不确定度分量的计算合成,得出被测样品中氮含量测量结果的标准不确定度和扩展不确定度.     

光电直读光谱法测定纯铝中铁含量的测量不确定度评定

对采用光电直读光谱法测定纯铝中铁含量的测量不确定度来源进行了详细的分析,确定不确定度主要来源是标准物质标准值的不确定度、高低标校正产生的变动性、工作曲线的变动性、测量结果的重复性等,并对各测量不确定度的分量进行了评定,计算了其合成标准不确定度,最后给出了扩展不确定度。     

原子荧光法测定水中总锑含量的不确定度评定

根据原子荧光光度法,用AFS-9700双道原子荧光光度计测定水样中的总锑含量,并且分析了主要的测量不确定度来源,即标准溶液引入的不确定度、建立工作曲线引入的不确定度、回收率引入的不确定度和重复测量样品引入的不确定度,对测量不确定度进行计算和评定,合成测得总锑含量的不确定度为0.10?g/L。     

Uncertainty in liquid chromatographic analysis of pharmaceutical product: influence of various uncertainty sources

An ISO GUM measurement uncertainty estimation procedure was developed for a liquid-chromatographic drug quality control method-assay of simvastatin in drug formulation. In quantification of uncertainty components several practical approaches for including difficult-to-estimate uncertainty sources (such as uncertainty due to peak integration, uncertainty due to nonlinearity of the calibration curve, etc.) have been presented. Detailed analysis of contributions of the various uncertainty sources was carried out. The results were calculated based on different definitions of the measurand and it was demonstrated that unequivocal definition of the measurand is essential in order to get rigorous uncertainty estimate. Two different calibration methods - single-point (1P) and five-point (5P) - were used and the obtained uncertainties and uncertainty budgets were compared. Results calculated using 1P and 5P calibrations agree very well. The uncertainty estimate for 1P is only slightly larger than with 5P calibration.     

Establishment of traceability of ammonium nitrogen determination in wastewater

A case study is presented for the establishment of traceability for ammonium nitrogen determination in wastewater in a routine laboratory in order to fulfil the requirements of ISO/IEC standard 17025. The necessary relevant information was obtained from the method validation data, the quality control data and equipment calibration certificates. The method of measurement is described together with the measurement equation, selected traceable reference standards and the associated measurement uncertainty. The major sources of uncertainty of the result of measurement were identified and the combined uncertainty was calculated. Identification of the main uncertainty sources represents the basis for target operations for reducing the measurement uncertainty of this determination.     

原子荧光光谱法测定方便米饭中砷的测量不确定度评定

介绍了原子荧光光谱法测定方便米饭中砷的测量不确定度评定方法,该法根据最小二乘法原理计算校准曲线的标准不确定度,并充分分析和识别分析过程中的不确定度来源,较为全面地评定了测量不确定度,该法对原子吸收光谱法、电感耦合等离子发射光谱法和原子荧光光谱法等测定结果的不确定度评定具有参考作用。     

Uncertainty evaluation of the thermal expansion of simulated fuel

Thermal expansions of simulated fuel (SS1) are measured by using a dilatometer (DIL402C) from room temperature to 1900 K. The main procedure of an uncertainty evaluation was followed by the strategy of the UO₂ fuel. There exist uncertainties in the measurement, which should be quantified based on statistics. Referring to the ISO (International Organization for Standardization) guide, the uncertainties of the thermal expansion are quantified in three parts—the initial length, the length variation, and the system calibration factor. Each part is divided into two types. The A type uncertainty is derived from the statistical iterative measurement of an uncertainty and the B type uncertainty comes from a non-statistical uncertainty including a calibration and test reports. For the uncertainty evaluation, the digital calipers had been calibrated by the KOLAS (Korea Laboratory Accreditation Scheme) to obtain not only the calibration values but also the type B uncertainty. The whole system, the dilatometer (DIL402C), is composed of many complex sub-systems and in fact it is difficult to consider all the uncertainties of sub-systems. Thus, a calibration of the system was performed with a standard material (Al₂O₃), which is provided by NETZSCH. From the above standard uncertainties, the combined standard uncertainties were calculated by using the law of a propagation of an uncertainty. Finally, the expanded uncertainty was calculated by using the effective degree of freedom and the t-distribution for a given confidence level. The uncertainty of the thermal expansion for a simulated fuel was also compared with those of UO₂ fuel.     

2011年约稿： 电感耦合等离子体原子发射光谱法测定铜合金中锆量的不确定度评定

讨论了采用电感耦合等离子体发射光谱法测定铜合金中锆量分析结果不确定度产生的原因。建立了数学模型,对测量重复性,标准溶液,标准曲线变动性,试液体积,试样称量,数字修约等引起的不确定分量进行评定,计算了合成标准不确定度和扩展不确定度,并给出铜合金中锆量测定结果的报告。评定结果表明：测量重复性,标准曲线线性回归引起的不确定度对总不确定度影响最大。所以,在测定中应进行多次平行测定,特别注意标准曲线的校正和绘制校准曲线所用标准样品的选择。     

Uncertainty of carboxyhaemoglobin determination in putrefied blood by headspace gas chromatography

The uncertainty of carboxyhaemoglobin (COHb) determination in post-mortem blood samples by headspace gas chromatography with the use of methanizer and flame ionization detector was estimated. Four main components of uncertainty were identified, i.e. calibration, measurement repeatability, standard solutions preparation and sample preparation, and their contributions to the combined uncertainty were determined. The calibration step was the dominating source of uncertainty, counting for more than 39 % of overall variance. The contribution of remaining sources to the combined uncertainty was lower than 31 % (measurement repeatability), 21 % (standards preparation) and 12 % (sample preparation). The calculated absolute expanded uncertainty in samples containing 3.8–82 % mass fraction of COHb ranged between 2.2 % and 2.6 % (coverage factor 2), depending only slightly on the analyte level in the analysed sample.     

原子吸收光谱法测量质量控制研究

以原子吸收光谱法对锌合金标准物质中的铜元素定值为例,运用田口方差分析方法对定值数据进行分析处理,实现元素定值过程的质量控制。从实验设计方案的角度确定实验过程的不确定度,对溶解、等份稀释、仪器校准三部分的实验步骤分别进行数据处理,计算各部分方差波动对总实验数据波动的贡献率,从而确定最主要的不确定度来源。     

高效液相色谱法测定氨基酸口服液中L-色氨酸的不确定度评定

采用高效液相色谱法测定氨基酸口服液中L-色氨酸的含量,对测量结果的不确定度进行评定。结果表明,标准曲线校准和测量重复性是测量过程中不确定度的主要来源,其中标准曲线校准对合成不确定度的影响最大。当氨基酸口服液中L-色氨酸的测定结果为8.8μg/mL时,其扩展不确定度为1.1μg/mL。