共查询到17条相似文献,搜索用时 203 毫秒
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依据国标GB/T 22388-2008规定,采用高效液相色谱法对液态奶中三聚氰胺的含量进行了检测。建立数学模型,分析确定检测液态奶中三聚氰胺含量的不确定度来源,并对测量过程中的不确定度分量进行逐层分析与合成,得到合成标准不确定度和扩展不确定度分别为0.054 mg/kg和0.11 mg/kg。计算结果显示由样品溶液测量重复性、标准溶液测量重复性、标准溶液配制过程引入的不确定度分量对合成标准不确定度贡献较大,是不确定度的主要来源;由样品称量、定容引入的不确定度相对来说较小。 相似文献
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通过铬含量测量不确定度的数学模型的建立,分析石墨炉原子吸收法测定胶囊中铬含量的测量不确定度的主要来源。通过石墨炉原子吸收法,对于药用胶囊中铬离子含量为1.96mg/kg的样本,进行相关测定,在置信因子为2时,扩展不确定度为0.2597mg/kg,测量结果范围在(1.96±0.2597)mg/kg。结论发现影响不确定度的因素主要为溶液配制和回收率等,在以后计量测定时,应该注意,保证准确度。 相似文献
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本文依据GB/T20387-2006《纺织品—多氯联苯残留量的测定》方法,对纺织品中多氯联苯残留量的测量不确定度的来源进行分析。以2、4、5-三氯联苯为分析对象,对测试过程中引入的不确定度各个分量进行了评定与合成。当2、4、5—三氯联苯测定结果为0.506mg/kg时,扩展不确定度为0.036mg/kg,并给出了检测结果不确定度表达式。 相似文献
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采用超高效液相色谱-串联质谱法(UPLC-MS/MS)测定了化妆品中丙烯酰胺含量,并对其进行了不确定度评定。根据 JJF 1059.1-2012《测量不确定度评定与表示》 建立测定化妆品中丙烯酰胺含量的计量学数学模型,分析和量化各不确定度分量。采用该方法检测的化妆品中丙烯酰胺的合成不确定度为0.033mg/kg,扩展不确定度为0.066mg/kg。实验测定的化妆品中丙烯酰胺含量结果为(0.502±0.066)mg/kg(k=2,置信概率P=95%)。评定结果表明,实验的不确定度主要由标准溶液配制和标准曲线拟合引入。 相似文献
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依据GB/T 18414.1-2006《纺织品含氯苯酚的测定第1部分:气相色谱—质谱法》测定纺织品中含氯苯酚,以2,3,5,6-四氯苯酚(2,3,5,6-TeCP)为例,对整个测量过程中不确定来源进行了分析,并对不确定度各个分量进行了评定、合成,最后给出了合成不确定度和有效自由度。当2,3,5,6-TeCP测定结果为0.472mg/kg时,扩展不确定度为0.084 mg/kg,并给出了结果不确定度表达式。 相似文献
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《现代测量与实验室管理》2015,(4)
建立了高效液相色谱法(HPLC)测定戊醛中的催化剂含量不确定度评定的数学模型。通过对整个测定过程中各种不确定度因素的研究,分析和评定了不确定度的来源,确定了不确定度分量和合成不确定度。结果表明,当戊醛中的催化剂含量为848mg/kg时,其扩展不确定度为6mg/kg(取包含因子k=2,置信概率约为95%),其中标准物质的纯度、标准样品和样品测量重复性对测量不确定度的影响较大,实验室应对其采取措施,减低不确定度。 相似文献
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A method is described for the determination of tributyltin (TBT) in NRCC sediment CRM PACS-2 by isotope dilution (ID) analysis using HPLC-ICPMS. Reverse spike ID analysis was performed to determine the accurate concentration of a 117Sn-enriched TBT spike using a well-characterized natural abundance TBT standard. The accuracy of the latter is critical for obtaining reliable results. A unique approach, using hydride generation GC/MS, was developed to quantify the inorganic Sn and dibutyltin impurities in the natural abundance TBT standard. The true natural abundance TBT standard concentration was obtained following correction for these impurities. The total Sn concentration in the natural abundance TBT standard was determined by ID analysis using an enriched inorganic 117Sn following closed vessel mixed-acid digestion. Calibration of the enriched inorganic 117Sn standard was achieved by reverse ID analysis against a natural abundance inorganic tin standard prepared from the high-purity metal. An overall uncertainty associated with the present method was estimated, to which the uncertainties arising from measurement of the natural abundance TBT concentration, from the measurement of the isotope ratio in the spiked sample and in the reverse ID calibration solutions, and from estimation of the extraction efficiency were the main contributors. A concentration of 1.018 +/- 0.054 mg kg(-1) (expanded uncertainty, k = 2) as tin was obtained for TBT in PACS-2 using the present method, in excellent agreement with the certified value of 0.98 +/- 0.13 mg kg(-1) (95% confidence interval). A TBT concentration of 0.97 +/- 0.11 mg kg(-1) (expanded uncertainty, k = 2) as tin in PACS-2 was determined using the standard additions technique. Much smaller expanded uncertainty was obtained with ID, clearly demonstrating its superiority in providing more accurate and precise results over the method of additions. A detection limit (3sigma) of 0.02 mg kg(-1) for TBT, based on a 0.5-g subsample, was obtained. 相似文献
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目的 对气相色谱内标法测定塑料制品中乙苯和苯乙烯含量进行不确定度评定,为塑料制品中乙苯、苯乙烯含量测定的准确性提供参考。方法 依据GB 31604.16—2016采用气相色谱内标法对塑料制品中乙苯和苯乙烯含量进行测定,根据相应的测量模型,分析不确定度主要影响因素的来源,并对各影响因素引入的相对标准不确定度进行评估。结果 测量塑料制品中乙苯、苯乙烯的扩展不确定度分别为(23.83±1.50)、(23.90±1.26)mg/kg(P=95%、k=2)。结论 结果表明,混标工作液配制、试样重复测量、气相色谱仪性能是影响乙苯和苯乙烯含量测量不确定度的主要因素,应选择精度高且量程合适的量具,加强气相色谱仪的期间核查,提高实验人员操作的熟练水平,进一步减小测量不确定度,使测量结果更为准确、可靠。 相似文献
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为提高鸡蛋食品安全检测结果准确性,建立了一种液相色谱串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)测定鸡蛋中的利巴韦林及其代谢物总残留量的不确定度数学模型。依据SN/T 4519-2016《出口动物源食品中利巴韦林残留量的测定》中的方法,对整个检测过程进行了不确定度评定。不确定度分量主要来源有测量的重复性、回收率、样品的称量、样品前处理稀释和定容、标准溶液配制、标准曲线拟合及仪器测定引入。经评定鸡蛋中利巴韦林及其代谢物总残留量结果为X=(9.94±0.88)μg/kg, k=2; 其中标准曲线拟合过程中引入的不确定度分量影响最大。 相似文献
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Yang L Ding J Maxwell P McCooeye M Windust A Ouerdane L Bakirdere S Willie S Mester Z 《Analytical chemistry》2011,83(9):3371-3378
An accurate and precise method for the determination of arsenobetaine (AsB, (CH(3))(3)(+)AsCH(2)COO(-)) in fish samples using exact matching species specific isotope dilution (ID) liquid chromatography LTQ-Orbitrap mass spectrometry (LC-LTQ-Orbitrap-MS) and standard addition LC inductively coupled plasma mass spectrometry (LC-ICPMS) is described. Samples were extracted by sonication for 30 min with high purity deionized water. An in-house synthesized (13)C enriched AsB spike was used for species specific ID analysis whereas natural abundance AsB, synthesized and characterized by quantitative (1)H NMR (nuclear magnetic resonance spectroscopy), was used for reverse ID and standard addition LC-ICPMS. With the LTQ-Orbitrap-MS instrument in scan mode (m/z 170-190) and resolution set at 7500, the intensities of [M + H](+) ions at m/z of 179.0053 and 180.0087 were used to calculate the 179.0053/180.0087 ion ratio for quantification of AsB in fish tissues. To circumvent potential difficulty in mass bias correction, an exact matching approach was applied. A quantitatively prepared mixture of the natural abundance AsB standard and the enriched spike to give a ratio near one was used for mass bias correction. Concentrations of 9.65 ± 0.24 and 11.39 ± 0.39 mg kg(-1) (expanded uncertainty, k = 2) for AsB in two fish samples of fish1 and fish2, respectively, were obtained by ID LC-LTQ-Orbitrap-MS. These results are in good agreement with those obtained by standard addition LC-ICPMS, 9.56 ± 0.32 and 11.26 ± 0.44 mg kg(-1) (expanded uncertainty, k = 2), respectively. Fish CRM DORM-2 was used for method validation and measured results of 37.9 ± 1.8 and 38.7 ± 0.66 mg kg(-1) (expanded uncertainty, k = 2) for AsB obtained by standard addition LC-ICPMS and ID LC-LTQ-Orbitrap-MS, respectively, are in good agreement with the certified value of 39.0 ± 2.6 mg kg(-1) (expanded uncertainty, k = 2). Detection limits of 0.011 and 0.033 mg kg(-1) for AsB with LC-ICPMS and ID LC-LTQ-Orbitrap-MS, respectively, were obtained demonstrating that the technique is well suited to the determination AsB in fish samples. To the best of our knowledge, this is first application of species specific isotope dilution for the accurate and precise determination of AsB in biological tissues. 相似文献
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