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目的评定氢化物原子荧光法测定人发中砷含量的不确定度。方法以人发标准样品为分析对象,依据化学分析中不确定度的评估指南等指导性文件,分析测定过程中砷含量测定值(C)、样品处理后的总体积(V)、样品称量值(m)以及重复测量(rep)等多个不确定度分量,计算检测结果的合成标准不确定度和扩展不确定度。结果本文方法测定人发中砷含量的不确定度评定结果为:人发样品中砷的含量为(0.57±0.06)mg/kg,置信概率(p)=95%,自由度(υeff)=4。结论本文方法测量不确定度的主要来源是重复性和校准曲线,测定结果在标准物质给出的含量范围之内。 相似文献
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目的建立自动顶空-气相色谱(HS-GC)内标曲线法测定血中乙醇含量的不确定评估方法。方法从分析测定程序着手,依据不确定度评定的指导性文件,分析不确定度来源,量化不确定度分量,计算检测结果的合成标准不确定度和扩展不确定度。结果各相对不确定度来自于检材重复性检测为3.4%,乙醇标准溶液为0.71%,检材为0.61%,叔丁醇内标溶液为0.41%,标准曲线为1.1%,气相色谱仪为1.3%,血液中乙醇的相对扩展不确定度为3.9%。结论血液中乙醇含量的不确定度主要来源于检材重复性检测、气相色谱仪、乙醇标准曲线。 相似文献
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毒物定量分析测量不确定度评定 总被引:1,自引:1,他引:0
第四讲 测量不确定度的评定、合成方法及运算公式
测量不确定度评定中,JJF1059—1999《测量不确定度评定与表示》给出评定的要求及方法,主要分A类评定和B类评定。这里就毒物定量分析特点作简要介绍,以方便实施。 相似文献
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Peter D. Maskell Calum Holmes Margaux Huismann Struan Reid Martin Carr Benjamin J. Jones Dawn L. Maskell 《Science & justice》2018,58(4):271-275
It is common for forensic practitioners to calculate an individual's likely blood alcohol concentration following the consumption of alcoholic beverage(s) for legal purposes, such as in driving under the influence (DUI) cases. It is important in these cases to be able to give the uncertainty of measurement on any calculated result, for this reason uncertainty data for the variables used for any calculation are required. In order to determine the uncertainty associated with the alcohol concentration of beer in the UK the alcohol concentration (%v/v) of 218 packaged beers (112 with an alcohol concentration of ≤5.5%v/v and 106 with an alcohol concentration of >5.5%v/v) were tested using an industry standard near infra-red (NIR) analyser. The range of labelled beer alcohol by volume (ABV's) tested was 3.4%v/v – 14%v/v. The beers were obtained from a range of outlets throughout the UK over a period of 12?months. The root mean square error (RMSE) was found to be ±0.43%v/v (beers with declared %ABV of ≤5.5%v/v) and ±0.53%v/v (beers with declared %ABV of >5.5%v/v) the RMSE for all beers was ±0.48%v/v. The standard deviation from the declared %ABV is larger than those previously utilised for uncertainty calculations and illustrates the importance of appropriate experimental data for use in the determination of uncertainty in forensic calculations. 相似文献
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Derek Draft D.D.S. Victoria S. Lucas Ph.D. Fraser McDonald Ph.D. Manoharan Andiappan Ph.D. Graham Roberts M.D.S. 《Journal of forensic sciences》2019,64(5):1506-1509
The expression of uncertainty is defined by the standard deviation and is usually expressed in multiples of the standard deviation (±1sd, ±2sd, and ±3sd). The objective was to use weighting of the sd calculation by the number or count of subjects for each tooth development stage. A comparison shows the difference between the range of uncertainty using the unweighted sd and the weighted sd. The range of uncertainty related to Dental Age Estimation is statistically significantly greater (p < 0.001) for the weighted sd compared to the unweighted sd. It is concluded that the number of subjects for each Tooth Development Stage in the Reference Data set should be included in the calculation for a single Dental Age Estimation using the Simple Average Method when presenting the uncertainty associated with the point estimate of the “mean” for Dental Age Estimation of a single subject of unknown age. 相似文献
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Measurement of Uncertainty for Aqueous Ethanol Wet‐Bath Simulator Solutions Used with Evidential Breath Testing Instruments 下载免费PDF全文
Rong‐Jen Hwang Ph.D. Jada Beltran B.A. Craig Rogers B.A. Jeremy Barlow M.S. Gerasimos Razatos M.B.A. B.S. 《Journal of forensic sciences》2016,61(5):1359-1363
Aqueous ethanol wet‐bath simulator solutions are used to perform calibration adjustments, calibration checks, proficiency testing, and inspection of breath alcohol instruments. The Toxicology Bureau of the New Mexico Department of Health has conducted a study to estimate a measurement of uncertainty for the preparation and testing of these wet‐bath simulator solutions. The measurand is identified as the mass concentration of ethanol (g/100 mL) determined through dual capillary column headspace gas chromatography with flame ionization detector analysis. Three groups were used in the estimation of the aqueous ethanol wet‐bath simulator solutions uncertainty: GC calibration adjustment, GC analytical, and certified reference material. The standard uncertainties for these uncertainty sources were combined using the method of root‐sum‐squares to give uc = 0.8598%. The combined standard uncertainty was expanded to U = 1.7% to reflect a confidence level of 95% using a coverage factor of 2. This estimation applies to all aqueous ethanol wet‐bath simulator solution concentrations produced by this laboratory. 相似文献
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目的对研制的二乙酰吗啡盐酸盐标准物质进行定值,并评定定值结果的不确定度。方法采用定量核磁共振法和质量平衡法进行定值;采用液质联用法用于有机物杂质的定性分析,采用电感耦合等离子质谱法、离子色谱法、顶空-气质联用法和卡尔费休滴定法测定无机阳离子、阴离子、挥发性有机溶剂残留和水分等杂质的含量。结果定量核磁共振法的纯度为95.6%,不确定度为0.13%;质量平衡法的纯度为95.3%,不确定度为0.93%。结论二乙酰吗啡盐酸盐标准物质的纯度值为95.6%,扩展不确定度为1.2%(k=2)。 相似文献