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能力验证及其评价 总被引:4,自引:0,他引:4
马冲先 《理化检验(化学分册)》2005,41(11):861-864,870
The definitions, purposes and uses of proficiency testing and interlaboratory comparison were expounded in detail. Main types of proficiency testing were illustrated. Special emphases were made on the organization, practice and evaluation of the planning of proficiency testing. Related policies about proficiency testing given by the China National Accreditation Board for Laboratories (CNAL) were also briefly introduced. 相似文献
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舒晓莲陈鹰李杰 《理化检验(化学分册)》2018,(11):1281-1286
为全面、客观、科学地了解和评价上海市有关实验室对水产品中磺胺类药物(SAs)残留量的检测能力,计划并实施了水产品中SAs残留量检测能力的验证。参加本项目的实验室达17家,通过养殖给药方式制备了阳性鱼肉样品。采用单因子方差分析法和平均值一致性检验法对样品进行均匀性和稳定性检验。对各参加实验室上报结果进行稳健统计分析,采用Z比分数评定各参加实验室的结果。17家资质实验室中获得满意结果的有15家,水产品中磺胺类药物残留检测能力总体较好。对数据结果分析表明:样品前处理和标准物质的选用是最容易引入误差的环节。 相似文献
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将烟丝样品置于温度(20±1)℃及相对湿度(60±3)%条件下平衡24h。称取此样品4.0g置于Dionex ASE 350萃取仪的34 mL萃取池中,用正己烷作为溶剂进行加速溶剂萃取(ASE)。加速萃取的温度为100℃,静态萃取时间为5min,循环次数为2次。于萃取液中加入乙酸苯甲酯内标(100mg·L^-1)溶液0.50mL,混匀后经0.45μm滤膜过滤,取滤液进行气相色谱-串联质谱法分析。采用HP-5MS毛细管色谱柱(30m×0.25mm,0.25μm),在60~280℃温度区间程序升温模式分离后,按电子轰击离子源和多反应监测模式条件进行串联质谱测定。所测定的5种羧酸苯乙酯的质量浓度均在0.10~10.00mg·L^-1内与其对应的峰面积之间呈线性关系,其检出限(3S/N)均为0.01mg·L^-1。按标准加入法测定了方法的回收率,结果为91.0%~107%,测定值的相对标准偏差(n=6)均小于10%。同一批次内和不同批次间外加标记物的变异系数(CVi)分别为5.8%~8.8%和6.3%~8.4%,说明加香工序的均匀性良好。 相似文献
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A. V. Harms 《Accreditation and quality assurance》2009,14(5):253-261
In this paper, a new data evaluation method for proficiency test exercises consisting of a combination of a z-test, a zeta test and an uncertainty outlier test is presented. This new method is compared with eight other evaluation methods
(both measurement uncertainty using and measurement uncertainty ignoring) in common use and/or recommended by ISO 13528. The
data set used to test the evaluation methods is real data and consists of the 95Nb results of the National Physical Laboratory Environmental Radioactivity Proficiency Test Exercise 2007. The evaluation
of 14 out of 32 results were affected by the choice of method. 相似文献
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Debeljak Z Srecnik G Madić T Petrović M Knezević N Medić-Sarić M 《Journal of chromatography. A》2005,1062(1):79-86
Instead of usual rationale for chromatographic fingerprint based sample identification which relies upon visual inspection or principal component analysis of raw or aligned chromatograms novel nonparametric statistical measure of fingerprint set homogeneity is proposed. Randomization test is applied for significance analysis of fingerprint set homogeneity while average maximum crosscorrelation is used as a merit function. Chromatogram sets generated by random selection from standard and unknown sample chromatogram collections are compared with respect to merit function values with set of chromatograms that represents standard and/or unknown sample. In that instance fingerprint homogeneity significance is represented by the fraction of random chromatogram sets that have higher merit values than the standard and/or unknown sample sets. A set of peptide maps corresponding to different haemoglobin variants has been selected for evaluation of proposed test. This approach is compared to chromatogram alignment based on correlation optimized warping coupled with principal component or cluster analysis. Proposed method is simple i.e. straightforward sample identification procedure which reliability has been evaluated here. Impact of this approach on peptide mapping validation and system suitability analysis is discussed. 相似文献
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A. V. Harms 《Accreditation and quality assurance》2009,14(6):307-311
A novel graphical method (‘Kiri plots’) for the presentation of proficiency test exercise results is presented. The Kiri plot
visualises the evaluation of the proficiency test results based on three statistical tests (the z score, the zeta score and the relative uncertainty outlier test) by defining six zones including a central “in agreement”
zone. 相似文献
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根据国家地表水环境质量监测网监测任务要求和环境监测的实际需要,制备了水中易释放氰化物能力验证样品。通过均匀性、稳定性检验以及量值一致性评价,研制的样品均匀性良好,在3℃~6℃冷藏避光保存条件下1年内稳定,样品配制值与多家实验室协作测定结果一致。探讨了样品在能力验证活动中的应用,共有来自全国11个省的32家实验室参加了水中易释放氰化物的能力验证计划,实验室满意率在80%以上,实验室结果出现有问题或不满意主要是由于样品前处理以及检测过程质量控制不当导致的。经检测及实验室反馈的数据验证,该能力验证样品能够应用于能力验证活动。 相似文献
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Daniel C. Lima Ana M.P. dos Santos Rennan G.O. Araujo Ieda S. Scarminio Roy E. Bruns Sergio L.C. Ferreira 《Microchemical Journal》2010,95(2):222-226
The development of a homogeneity study during the preparation of a wheat flour laboratory reference material (LRM) for use in the quantification of metals and metalloids is reported. Inductively coupled plasma optical emission spectrometry (ICP OES) was used with validation performed using a certified reference material of wheat flour furnished by the National Institute of Standards and Technology (NIST). Copper, iron, manganese, phosphor, strontium and zinc were studied in a within-bottle homogeneity test whereas barium, copper, iron, zinc, manganese, strontium, phosphor and calcium were included in a between batch homogeneity study. Standard univariate analysis of variance (ANOVA) was performed for all analytes. Furthermore an alternative multivariate analysis for homogeneity is proposed by performing ANOVA of principal component scores and by inspection of principal component score graphs and hierarchical cluster analysis dendrograms. The ANOVA F-tests performed on both, the univariate and multivariate parameters, were not significant at the 95% confidence level and indicated homogeneous wheat flour samples. A 10 kg amount of material was processed, which was distributed in 100 bottles, each containing 100 g. For the between-bottle homogeneity test, three replicates were taken from each of 10 bottles selected of the 100 bottles obtained. The results were evaluated using an F-test, which demonstrated no significant difference for the between-bottle results. It is indicative that this material is homogeneous. Afterwards, the influence of the sample mass on the homogeneity of the material was also evaluated by quantification of the elements for 100, 300, 500, 700 and 1000 mg sample masses with all the experiments being performed in triplicate. The F-test was also used for evaluation of these results and demonstrated that the material is homogeneous for masses taken in the 100 to 1000 mg range. All these results were further evaluated employing the principal component analysis (PCA) and hierarchical cluster analysis (HCA) multivariate techniques. Both techniques also demonstrated that the material is perfectly homogeneous for use as laboratory reference material. 相似文献
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Pedro Rosario José Luis Martínez José Miguel Silván 《Accreditation and quality assurance》2008,13(9):493-499
In analytical chemistry, proficiency testing usually consists in tests that laboratories conduct under routine conditions
and report the result to the PT provider who then converts the result to a score which helps the participant to assess the
accuracy of the result. The aim of this work is to show PT providers, accreditations bodies, and participating laboratories
that different scoring results can be achieved depending on the evaluation system selected. The influence of different evaluation
techniques on the results of an interlaboratory comparison for determination of gold in precious metals alloys was investigated.
Results from 19 participating laboratories were evaluated by means of the three procedures: (1) classical statistical approach—outliers
detection; (2) robust methods—(2A) robust procedure and (2B) ISO 13528; and (3) fitness for purpose. Evaluation of the same
PT data revealed very interesting issues depending on the different scoring systems that were used and the robustness of the
statistical methods used for detecting outliers. As a general rule, laboratories with scoring Z > 2 offered clearly poorer performance in robust approaches than classical ones. In order to support this first evidence,
we evaluated a second data set with results from 24 laboratories (mercury from soil samples) by means of the four mentioned
approaches. Selection and comparison of different scoring systems must be done very carefully, because sometimes they are
not the best approach for studying the data population or the more appropriate one for evaluating the distribution of the
data. Finally it should be taken into account that sometimes the robust scoring systems are not always suitable for evaluating
the results of some PT schemes. 相似文献
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Anna Martínez‐Villalba Oscar Núñez Encarnación Moyano M. Teresa Galceran 《Electrophoresis》2013,34(6):870-876
Veterinary medicines are widely administered to farm animals since they keep animals healthy at overcrowded conditions. Nevertheless the continuous administration of medicines to farm animals can frequently lead to the presence of residues of veterinary drugs in consumption products. Amprolium is a quaternary ammonium compound used in the treatment of coccidiosis. In this paper, a method based on CZE to analyze residues of amprolium in eggs was developed and validated for the first time. Parameters such as electrolyte type, concentration, and pH were optimized. In order to improve sensitivity, field‐amplified sample injection (FASI) was used for in‐line preconcentration after a quick and simple sample treatment based on SPE (Envi‐Carb). During method‐validation studies using egg samples, a matrix interference was found at the migration time of amprolium. This compound was identified as thiamine and confirmed by MSn experiments using CEcoupled to MS (CE‐MS) with an ion‐trap mass analyzer. CZE conditions were reoptimized to separate thiamine from amprolium allowing the quantification of amprolium in eggs at concentrations down to 75 μg/kg, which are far below the MRL‐legislated values. 相似文献
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Göran Nilsson 《Accreditation and quality assurance》2001,6(4-5):147-150
Data from proficiency testing can be used to increase our knowledge of the performance of populations of laboratories, individual
laboratories and different measurement methods. To support the evaluation and interpretation of results from proficiency testing
an error model containing different random and systematic components is presented. From a single round of a proficiency testing
scheme the total variation in a population of laboratories can be estimated. With results from several rounds the random variation
can be separated into a laboratory and time component and for individual laboratories it is then also possible to evaluate
stability and bias in relation to the population mean. By comparing results from laboratories using different methods systematic
differences between methods may be indicated. By using results from several rounds a systematic difference can be partitioned
into two components: a common systematic difference, possibly depending on the level, and a sample-specific component. It
is essential to distinguish between these two components as the former may be eliminated by a correction while the latter
must be treated as a random component in the evaluation of uncertainty.
Received: 20 November 2000 Accepted: 3 January 2001 相似文献
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Robin Willink 《Accreditation and quality assurance》2009,14(7):353-358
This paper builds on recent letters to the editor to consider different ways in which the ‘sample standard deviation’ of a
set of repeated measurements might be used in the expression of accuracy or uncertainty. A distinction is made between using
the sample standard deviation, s, to calculate a figure of merit for the measurement procedure and using s to express uncertainty in the estimate of a measurand. In particular, we consider whether s should be adjusted for bias. It is shown that most procedures involving s are valid without the application of any such adjustment. The paper emphasizes the importance of clear definitions and an
unambiguous statement of purpose, and also emphasizes the need for a distinction in notation between a random variable and
its observed value. 相似文献