微波消解-ICP法测定土壤中重金属元素的不确定度评定

对微波消解-电感耦合等离子发射光谱法测定土壤样品中Cu、Pb、Zn、Cr、Ni的不确定度进行评估,在测定过程中,对样品称量、消解、定容体积、标准溶液的配制、曲线拟合、仪器测量重复性等影响不确定度的分量进行分析,按《测量不确定度评定与表示》(JJF 1059—1999)的规定进行合成,最终给出扩展不确定度,为电感耦合等离子发射光谱法测量土壤中重金属元素的实验室质量控制和不确定度评定提供参考依据。     

热分解法测定水质中总氮的不确定度分析

采用实验测定和误差分析的方法,对TOC分析仪测定水质中总氮含量的不确定度进行了分析,测量过程中不确定度的来源有样品重复性测量、标准曲线拟合、标准溶液配制、测量仪器本身等,量化估算了不确定度的各分量。结果表明,标准曲线拟合是影响水质中总氮测定不确定度的主要因素,其次为标准溶液配制所产生的不确定度,样品重复性测量和测量仪器本身所产生的不确定度也不容忽视。同时提出了在测定过程中减小不确定度的有效途径。     

石墨炉原子吸收法测定土壤中镉的不确定度评定

评定了石墨炉原子吸收法测定土壤样品中镉的测量不确定度。在测定过程中,对样品称量、水分测定、样品消解、样品定容、标准溶液配制、标准曲线拟合等影响不确定度的分量进行了评定。按照《测量不确定度评定与表示》(JJF 1059.1—2012)的规定进行合成,给出了扩展不确定度,镉含量结果的表示式为(0.115±0.015)mg/kg,k=2。     

石墨炉原子吸收光谱法测定全血中铅的不确定度评定

根据《测量不确定度评定与评定表示指南》(JJF 1059-1999)建立了石墨炉原子吸收光谱法测定全血中铅不确定度的数学模型,分析了测试过程中不确定度的来源,并对各不确定度分量进行量化。本次测量的合成相对不确定度值为0.047 3,其中最大的分量是样品消化前处理重复测定引入的,其不确定度分量值为0.04。本次全血中铅测定结果为(130.7±12.4)μg/L,k=2,即测定结果置信水平为95%。     

X射线荧光光谱法测定土壤样品中铅的不确定度评定

用实例对X射线荧光光谱法测定土壤样品中铅的不确定度进行了评定.测量结果的不确定度由仪器综合稳定性、制样、标准物质、回归工作曲线、重复测量等所引入的不确定度分量组成.在对各个不确定度分量进行量化的基础上,通过合成得到测量结果的标准不确定度,再乘以95%置信概率下的扩展因子2,得到测量结果的扩展不确定度.     

离子色谱法测定PM_(2.5)中硫酸根离子含量不确定度评议

准确测定大气颗粒物中水溶性组份对分析污染物来源及身体健康具有重要意义。本文采用离子色谱法测定PM2.5中硫酸根离子含量,并对测定的不确定度进行分析。分析过程不确定度来源是样品重复性测量引入不确定度,样品测量准确性引入不确定度和标准曲线的不确定度。应用不确定度评定理论,计算硫酸根离子的合成不确定度。结果表明,滤膜中硫酸根离子本底浓度高低与剪裁滤膜环节是不确定度的主要来源。为了提高分析的准确性,建议使用本底低的滤膜,并取整张滤膜进行分析。     

水中放射性核素锶-90测量不确定度的评估

阐述了分析放射性核素产生不确定度因素比一般化学分析多的原因，通过采用鱼骨图法分析放射性核素锶-90测量实验中的不确定度和分析计算公式中的有关参数，了解到分析水中放射性核素锶-90时，主要受到样品测量、仪器探测效率、样品化学回收率和样品取样体积等4个方面的不确定度因素影响。     

土壤中六六六和滴滴涕残留量的测量不确定度评定

本文采用加速溶剂萃取-固相萃取净化-气相色谱法测定土壤样品中六六六和滴滴涕的残留量,并依据JJF1059和CNAS-GL06规范,评价了测量过程中的不确定度。结果表明,8种有机氯农药在高于定量下限的较宽浓度范围内的扩展不确定度(以%计)无显著性差异,校准过程引入的不确定度所占比重随着被测物浓度的降低显著提高。     

底质样品中总汞测定方法的几点讨论

在《水和废水监测分析方法》第三版中,底质中总汞测定采用了冷原子吸收法和冷原子荧光法,两种方法对于样品的前处理(分解)都是一样。在我们用冷原子荧光法测定几条河流底质中的总汞时,数据往往是检不出,而实际上又存在污染源,通过仔细分析,发现是在样品前处理及条件控制上有问题,进行对比实验后结果表明: 1.在前处理以盐酸羟胺滴定KMnO_4至颜色退尽不恰当,因为对土壤底泥样品,摇动产生的混浊和它本身的底色会影响终点判定,难以观察颜色是否完全退尽。如果坚持“退尽”     

用波长色散X射线荧光光谱测定土壤中铬的不确定度

运用测量不确定度评定与表示的理论,分析了波长色散X射线荧光光谱仪测定土壤中铬的不确定度,得出测定铬的不确定度为1.0mg/kg.     

火焰原子吸收法测定水中铁、锰含量的不确定度评定

从样品消解、分析、计算全过程对火焰原子吸收法测定水中铁、锰进行分析,根据JJF 1059-1999对其测量不确定度进行评定。结果表明,测定水中铁的不确定度主要来源于消解过程、标准溶液及配制、重复测定样品;测定水中锰的不确定度主要来源于消解过程、工作曲线拟合、标准溶液及配制。水中铁、锰含量的结果可分别表示为：（2.58±...     

Feasibility study of preparation and certification of reference materials for nitrogen dioxide and sulfur dioxide in diffusive samplers

This paper presents the results of a feasability study for the preparation and certification of reference materials (RMs) for nitrogen dioxide (NO(2)) and sulfur dioxide (SO(2)) in diffusive samplers. RMs for NO(2) were prepared by exposure to gas mixtures in a chamber while the RMs for SO(2) were prepared by liquid spiking. Certification of RMs for NO(2) was found feasible with a certified uncertainty of 5.8% and a proposed shelf life of 5 years. The uncertainty was calculated with contribution from the homogeneity of preparation, stability and transport of the CRMs and from an external verification of the certified value. To reach 5.8% of uncertainty, the contribution of the differences between the results of analysis by ion chromatography and colorimetry must be eliminated. It is proposed to solve this by pre-extracting the samplers with water before analysis. The results of this study indicate that the samplers are stable for at least two years before and after exposure when stored in a refrigerator. By contrast, the certification of RMs for SO(2) was found to not be feasible due to instability problems. This instability was attributed to reaction of sulfate on the walls of the samplers. Alternatively, the preparation of RMs by simultaneous exposure to SO(2) and NO(2) has been tested. Satisfying homogeneities has been reached both for NO(2) and SO(2).     

氢化物发生原子荧光光度法测定水中锑的不确定度评定

介绍了原子荧光光度法测定水中锑的不确定度评定方法,分析和识别在测定过程中的不确定度来源,较为全面地评定了测量不确定度,最后计算出测定结果的合成标准不确定度和扩展不确定度.结果表明,标准溶液配制过程和标准曲线拟合引起的不确定度是原子荧光光度法测定水中锑含量不确定度的主要来源.     

Assessment of sampling and analytical uncertainty of trace element contents in arable field soils

Assessment of trace element contents in soils is required in Germany (and other countries) before sewage sludge application on arable soils. The reliability of measured element contents is affected by measurement uncertainty, which consists of components due to (1) sampling, (2) laboratory repeatability (intra-lab) and (3) reproducibility (between-lab). A complete characterization of average trace element contents in field soils should encompass the uncertainty of all these components. The objectives of this study were to elucidate the magnitude and relative proportions of uncertainty components for the metals As, B, Cd, Co, Cr, Mo, Ni, Pb, Tl and Zn in three arable fields of different field-scale heterogeneity, based on a collaborative trial (CT) (standardized procedure) and two sampling proficiency tests (PT) (individual sampling procedure). To obtain reference values and estimates of field-scale heterogeneity, a detailed reference sampling was conducted. Components of uncertainty (sampling person, sampling repetition, laboratory) were estimated by variance component analysis, whereas reproducibility uncertainty was estimated using results from numerous laboratory proficiency tests. Sampling uncertainty in general increased with field-scale heterogeneity; however, total uncertainty was mostly dominated by (total) laboratory uncertainty. Reproducibility analytical uncertainty was on average by a factor of about 3 higher than repeatability uncertainty. Therefore, analysis within one single laboratory and, for heterogeneous fields, a reduction of sampling uncertainty (for instance by larger numbers of sample increments and/or a denser coverage of the field area) would be most effective to reduce total uncertainty. On the other hand, when only intra-laboratory analytical uncertainty was considered, total sampling uncertainty on average prevailed over analytical uncertainty by a factor of 2. Both sampling and laboratory repeatability uncertainty were highly variable depending not only on the analyte but also on the field and the sampling trial. Comparison of PT with CT sampling suggests that standardization of sampling protocols reduces sampling uncertainty, especially for fields of low heterogeneity.     

Monte Carlo assessment of uncertainty in the simulated hydrological response to land use change

We quantified the uncertainty in hydrological response for a set of land use change scenarios by varying plant parameters within realistic uncertainty bounds in a Monte Carlo analysis. The results show that simulated hydrological fluxes significantly change after the introduction of outwintering suckler cow management, despite the presence of a significant amount of output uncertainty due to uncertainty in the plant parameterisation. The key to a proper uncertainty assessment was to consider the uncertainty in the difference between the scenarios instead of the absolute uncertainty of each single scenario. Additionally, a sensitivity analysis showed that changing soil properties in response to land use change does not result in significantly different results in the scenario analysis.     

Fragmentary provisions for uncertainty disclosure and consideration in EA legislation,regulations and guidelines and the need for improvement

The consideration and disclosure of uncertainties is fundamental to a credible EA process, but little is known about the nature and type of requirements and guidance available to proponents, practitioners and decision makers about how to deal with uncertainties. This paper examines the provisions for considering and disclosing uncertainties in EA. Methods are based on a comparative review of uncertainty provisions in EA legislation, regulations and guidance documents under Canadian federal, provincial and territorial jurisdictions. Results show 10 types of provisions applied at different stages of the EA process with considerable jurisdictional variability and incoherence. The most common provision was that decision makers can request that project proponents provide more information, followed by the preparation of contingency plans, and that practitioners document their assumptions about data reliability. Most of these provisions were found in guidelines, versus legislation or regulations; and most addressed impact management, with very few provisions for addressing uncertainty during EA review and decision making. Current practices of uncertainty (non)disclosure and (non)consideration in EA can be explained, in part, by the superficial nature and limited extent of the requirements and guidance made available to EA practitioners, proponents, and decision makers. The existing requirements placed on proponents and practitioners to disclose and consider uncertainties are necessary, but insufficient. Stronger, more coherent and transparent requirements for those tasked with EA review and decision making to consider uncertainty information when disclosed, and the development of practical guidance on how to do so, are needed.     

原子荧光法测定废水中砷的不确定度评定

以原子荧光法测定油田废水中砷含量为实例,建立数学模型,分析和识别在分析过程中的不确定度来源,对测量中不确定度的各个分量进行了分步计算及合成,计算出测定结果的扩展不确定度0.74μg/L。通过计算和分析,结果表明,标准工作曲线拟合和方法回收率是原子荧光法测定油田废水中砷含量的不确定度的主要因素。     

Improving Efficiency Of Uncertainty Analysis In Complex Integrated Assessment Models: The Case Of The Rains Emission Module

Abstact Ever since the Regional Acidification Information and Simulation Model (RAINS) has been constructed, the treatment of uncertainty has remained an issue of major interest. In a recent review of the model performed for the Clean Air for Europe (CAFE) programme of the European Commission, a more systematic and structured uncertainty analysis has been recommended. This paper aims at contributing to the scientific debate how this can be achieved. Because of its complex structure on the one hand and limited research resources (time, computational capacities) on the other hand a full-blown uncertainty analysis in RAINS is hardly feasible. Therefore, all types of uncertainty require more efficient ways for uncertainty analysis. With respect to parameter uncertainty, we propose to focus research efforts for uncertainty analysis on key parameters. Among different approaches to select key parameters that have been discussed in the literature screening methods seem to be particularly appropriate for complex, deterministic Integrated Assessment models such as RAINS. Surprisingly, in Integrated Assessment modelling for air pollution problems of screening design have not been taken up so far. As a case study we consider the emission module of RAINS. We show that its structure allows for a straightforward and effective screening procedure