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 Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement   [SJR: 0.378]   [H-I: 30]   [26 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 0949-1775 - ISSN (Online) 1432-0517    Published by Springer-Verlag  [2355 journals]
• New challenges
• Authors: Ales Fajgelj
PubDate: 2018-01-09
DOI: 10.1007/s00769-017-1307-3

• National interlaboratory comparisons in the field of breath alcohol
analyzers calibration, performed in Poland, 2014–2016
• Authors: Piotr Janko; Robert Kordulasiński; Jolanta Wasilewska; Elżbieta Lenard
Pages: 335 - 345
Abstract: Abstract Proficiency testing (PT) and interlaboratory comparisons (ILC) are basic tools of external quality assurance in testing and calibration laboratories. Seeking to meet the needs and expectations of all stakeholders, the Central Office of Measures (GUM) provides ILC in the field of calibration of breath alcohol analyzers. This article describes a series of twelve bilateral ILCs conducted sequentially from December 2014 until July 2016. Eleven laboratories, accredited or in the process of preparation for accreditation, participated in these comparisons. Comparisons encompassed calibration of the same Intox II EC/IR analyzer at four test points: 0.10 mg/L, 0.25 mg/L, 0.41 mg/L, 1.52 mg/L. The results of participant performance evaluation, the results of the density measurements of participants’ liquid ethanol standards and the results of correlation analysis at four calibration points are presented. Nine out of eleven participants obtained all satisfactory results. One of the remaining laboratories confirmed the effectiveness of implemented remedial actions by successful participation in repeated ILC. Laboratories with satisfactory performance confirmed the declared uncertainty.
PubDate: 2017-12-01
DOI: 10.1007/s00769-017-1280-x
Issue No: Vol. 22, No. 6 (2017)

• Uncertainty estimation of the determination of chemical sum parameters in
water
• Authors: Tony Venelinov
Pages: 347 - 351
Abstract: Abstract Sum parameters (otherwise known as composite parameters) describe similar chemical, physicochemical or biological characteristics of different substances, substance groups or mixtures of substances. These might contain the same chemical element. Such parameters are total organic carbon or total bound nitrogen. Chemical oxygen demand is a shared chemical characteristic—the oxidizability of constituents by dichromate. The focus of the paper is on the uncertainty estimation of the determination of chemical sum parameters in water samples from method validation derived data—total organic carbon, chemical oxygen demand, biochemical oxygen demand, total bound nitrogen and total suspended solids. The results for the measurement uncertainty estimations according to ISO 21748 and ISO 11352, as only applicable to the field of water analysis, are presented and compared. Based on the results obtained and the experimental design, the use of ISO 11352 for the measurement uncertainty estimation is recommended. This international standard employs fewer determinations (a minimum number of eight measurements are required, compared to fifteen), fewer working days (one compared to five) and easier measurement uncertainty components’ calculations and even gives opportunity for routine laboratories to use standard solutions over the more expensive certified reference materials for the measurement uncertainty estimation during the method validation in water analysis.
PubDate: 2017-12-01
DOI: 10.1007/s00769-017-1276-6
Issue No: Vol. 22, No. 6 (2017)

• Investigation of homogeneity and stability of items for proficiency
testing of solid recovered fuels (SRF) analysis
• Authors: Barbara Jagustyn; Agnieszka Plis; Mariusz Mastalerz; Joanna Hrabak; Marek Ściążko
Pages: 355 - 360
Abstract: Abstract Solid recovered fuel (SRF) is made of waste and used as a substitute for fossil fuel. Physical and chemical analyses are needed to evaluate the usefulness of the waste in power and heat generation. This paper reports the assessment of homogeneity and stability of laboratory and analytical samples, with different particle size, obtained from three materials of different composition. The components of first material included soft plastics, plastics foam, composite packaging with the content of aluminum foil, cigarette filters, paper, cardboard, textiles, wood, and cotton. The second material mainly contained soft plastics and the needles from artificial Christmas trees, a lower amount of artificial leather, and aluminum foil. The third material was mainly composed of soft plastics and paper. The parameter used in the homogeneity and stability assessment was ash content on a dry basis. The homogeneity and stability assessment was carried out according to ISO 13528:2015; on the basis of a standard deviation for proficiency assessment calculated using the repeatability and reproducibility standard deviations from a previous collaborative study of precision of a measurement method. The homogeneity assessment was carried out using laboratory and analytical samples of SRF. Based on measurements of ash content, laboratory samples as the test items OB1 with a particle size below 4 mm were not sufficiently homogeneous, regardless of the SRF type, among our samples those with the largest particles. The analytical samples as the test items OB2 with a particle size below 1 mm and OB3 with a particle size below 0.5 mm were sufficiently homogeneous. For these samples, the stability assessment was carried out and studied samples were stable. The homogeneity and stability of SRF material were associated not so much with the grinding but the composition of the material.
PubDate: 2017-12-01
DOI: 10.1007/s00769-017-1283-7
Issue No: Vol. 22, No. 6 (2017)

• Analysis of findings throughout the cycles of accreditation of veterinary
diagnostic testing laboratories for diseases transmitted by products of
animal origin
• Authors: Patricia Weigert de Camargo; Elmiro Rosendo do Nascimento; Maria Helena Cosendey de Aquino
Pages: 361 - 367
Abstract: Abstract This work describes the frequency of findings registered in the assessment reports of 23 Brazilian animal health laboratories from 2008 to 2016. The study was conducted in consideration of the ISO/IEC 17025 requirements and normative documents issued by the Brazilian Accreditation Body [General Coordination for Accreditation (Cgcre)]. The general performance of these laboratories throughout the evaluation cycles was investigated. The types and number of findings reported in the assessments of these laboratories were analyzed according to the management and technical requirements of ISO/IEC 17025 and Cgcre’s normative documents. The laboratories’ performance was compared in consideration of the number of findings reported in the first and last assessments of each laboratory investigated.
PubDate: 2017-12-01
DOI: 10.1007/s00769-017-1284-6
Issue No: Vol. 22, No. 6 (2017)

• Determination and quality evaluation of six components in Zhou’s
Prescription through quantitative analysis of multi-components by single
marker
• Authors: Cuicui Gu; Fang Wu; Yanmei Cao; Lian Yin; Xu Zhang; Lihong Ye; Zhongying Zhou
Pages: 369 - 379
Abstract: Abstract Zhou’s Prescription is a compound prescription with traditional Chinese medicine, which is composed of 13 kinds of herbs and has been used to treat lung cancer in clinical practice for many years in China. Quantitative analysis of multi-components with single marker (QAMS) was used for the first time to analyze Zhou’s Prescription for the mass contents of six active ingredients, and chemometric methods were applied to evaluate its quality. Quercetin was selected as the internal standard serving as basis for relative correction factors (RCFs) determined using different HPLC instruments and columns. The contents of the active ingredients hydroxysafflor yellow A, rutin, hyperoside, isoquercitrin and quercitrin were calculated applying the RCFs. The stability and accuracy of QAMS were tested and verified by an external standard method (ESM). The accuracy was between 94.5 % and 100.4 % demonstrating the consistency of QAMS and ESM. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were applied to classify 21 batches of Zhou’s Prescription which were composed with supplies of the 13 herbs from different harvests at different producing regions. Among the 21 batches, a significant difference between the contents of the active ingredients was found which can be distinguished by chemometric methods. QAMS proved to be a promising and accurate method to quantify the active ingredients in Zhou’s Prescription also when resources of reference substances are limited. Moreover, the quality of Zhou’s Prescription is determined by the content of active ingredients scaled by HPLC. The method is based on QAMS combined with HCA and PCA to comprehensively evaluate the quality of Zhou’s Prescription composed of herbs of different sources.
PubDate: 2017-12-01
DOI: 10.1007/s00769-017-1287-3
Issue No: Vol. 22, No. 6 (2017)

• Trueness verification survey for blood lead concentration measurement in
Chinese clinical laboratories
• Authors: Shuai Yuan; Wei Wang; Jianping Li; Mingxia Liu; Junwei Xin; Fa L. He; Kun Zhong; Zhi G. Wang
Abstract: Abstract The results of trueness verification for blood lead measurement were analyzed in a 2016 nationwide external quality assessment (EQA) survey, in order to evaluate current approaches of blood lead measurement in Chinese Laboratories and their traceability to certified reference materials (CRMs). A panel of 2 frozen whole blood CRMs with values assigned by an absolute quantitative method was provided to 12 laboratories with satisfactory performances from the 2015 blood lead EQA scheme. Participants were required to measure the samples 5 times each day for 3 consecutive days and report all 15 data, which were then calculated for means and standard deviations. Data were statistically analyzed by adopted method groups, before comparing with the assigned values to assess the trueness of blood lead measurement using different approaches. Eleven laboratories reported on schedule, rendering a reporting rate of 91.7 %. The target values for the two batches were (37.6 ± 2.7) μg/L and (124.6 ± 4.5) μg/L, respectively. By the evaluation criterion of target value ± 20 µg/L, the pass rates were 72.7 % for the lower concentration and 54.5 % for the higher concentration, while 5 out of 11 laboratories delivered satisfactory results for both CRMs. The overall performance of the few participating laboratories in this EQA survey was basically acceptable by CLSI standard on the whole, yet barely desirable for the higher concentration. Therefore, trueness verification of blood lead measurement with CRMs is potentially necessary for national EQA schemes, which can be imperative as part of the validation procedures of analytical methods in clinical settings.
PubDate: 2017-12-20
DOI: 10.1007/s00769-017-1304-6

• Correction to: Combined uncertainty factor for sampling and analysis
• Authors: Michael H. Ramsey; Stephen L. R. Ellison
Abstract: Abstract In the penultimate paragraph of the original publication, a confidence interval of 93 mg/kg to 971 mg/kg was reported. These values should be 114.5 mg/kg to 786.2 mg/kg.
PubDate: 2017-12-18
DOI: 10.1007/s00769-017-1305-5

• Optimizing measurement uncertainty to reduce the risk and cost in the
process of conformity assessment
Abstract: Abstract Uncertainty in measurement is very important in the process of conformity assessment. As it is generally declared, based on the measured value of a property of an item, there is always the risk of incorrect decisions, which are of two types: an item accepted as “conforming” may actually be “non-conforming”, and an item rejected as “non-conforming” may actually be “conforming”. In order to reduce the risks associated with decision-making, it is required to reduce the measurement uncertainty to an acceptable level termed as “target uncertainty”. In order to reduce the uncertainty of a particular measurement, it would be necessary to focus on decreasing the uncertainties arising from the relevant components. There are always different solutions to reduce the uncertainties arising from each inclusive component. Each of these solutions imposes a different cost on the measurement system. Therefore, a solution should be selected, among several possible alternatives, to reduce the uncertainties arising from each relevant component and to impose the lowest cost to the measurement system to “target uncertainty”. Accordingly, in this paper through a case study, a model is presented that can reduce uncertainty with the lowest possible cost to the optimally needed level using a mathematical optimization technique. The mathematical model presented in this paper can be used in measurement uncertainty optimization in many laboratories, which require a reduction in uncertainty and the risks associated with decision-making based on measurement results. Furthermore, the use of the proposed model will help to reduce the unnecessary costs of analysis in different laboratory centers.
PubDate: 2017-12-08
DOI: 10.1007/s00769-017-1294-4

• Quality system implementation in the National Metrology Institute of
Montenegro
• Authors: Vanja Asanovic; Milena Raonic; Naina Cuturic-Knezevic; Goran Vukoslavovic; Milena Popovic; Vladan Jestrovic
Abstract: Abstract Accreditation of calibration laboratories is a means for achieving competence recognition and assuring customers that their calibration services are accurate and reliable. Moreover, it is a powerful tool for a National Metrology Institute (NMI), enabling the formal acceptance of its measurement results. It could be especially useful when calibration activities are performed in well-developed laboratories, which have participated successfully in interlaboratory comparisons but have been awaiting the publication of Calibration and Measurement Capabilities in the BIPM Key comparison database. This paper describes establishment and implementation of a quality management system in the NMI of Montenegro called Bureau of Metrology (MBM) that complies with ISO/IEC 17025. We have presented the results of the first audit evaluation, corrective actions, preparation of quality management documentation, measurement traceability, as well as advantages of being accredited. Our experience of implementing ISO/IEC 17025 for the accreditation of national calibration laboratories established within the MBM shows that strategic planning, establishment of long-term objectives, as well as the commitment to fulfilling standard requirements are the basis for acceptable calibration results. International acceptance of confidence and reliability of calibration services and measurement results provided by the MBM laboratories represents a useful marketing tool for promoting the image of the institution.
PubDate: 2017-12-04
DOI: 10.1007/s00769-017-1303-7

• The hitherto non-included component in the uncertainty budget for
gravimetric measurement of particulate matter concentration in a conduit
• Authors: Przemysław Kateusz
Abstract: Abstract This article discusses the accuracy of the gravimetric measurement method of total particulate matter concentration in waste gases where the basic assumption is that sample collection of dust-laden gas is done in a grid with a finite number of points in the conduit’s measurement plane. In this standard approach, the sample is assumed to be representative for dust-laden gas in the conduit, and consequently, the total particulate matter concentration measured for the sample is considered the mean concentration in the conduit. The article investigates this assumption against the standard-imposed number of sampling points and in view of spatial distributions of particulate matter concentration in industrial plants which—being continuous—are not identified in measuring practice. Possible distributions were simulated both for particulate matter concentration and for gas velocity in rectangular conduits, and the following were calculated: (a) an accurate mean particulate matter concentration in the measurement plane, based on its definition employing continuous distributions of particulate matter concentration and gas velocity and (b) the concentration in a sample, i.e. measured concentration. Measurement deviation between those concentrations was determined, which is specific for cumulative gas sampling. Using the obtained set of possible deviations, an estimation method was suggested for the relevant uncertainty component of the gravimetric method, which so far has not been taken into account in the industrial measurement accuracy analyses. It turns out that the level of this uncertainty component for measuring the mean particulate matter concentration in the conduit (resulting from “measurement discretization”) is not to be ignored.
PubDate: 2017-12-04
DOI: 10.1007/s00769-017-1302-8

• Measurements recovery evaluation from the analysis of independent
reference materials: analysis of different samples with native quantity
spiked at different levels
• Authors: Rui M. S. Cordeiro; Constantino M. G. Rosa; Ricardo J. N. Bettencourt da Silva
Abstract: Abstract Measurement uncertainty evaluation involves combining uncertainty components reflecting all relevant random and systematic effects: the precision and trueness uncertainty components, respectively. Typically, trueness is assessed through the analysis of various materials with known reference value, such as certified reference materials (CRMs) or spiked samples, from which it should be decided about the relevance and the need to correct measurement results for systematic effects. Algorithms proposed so far to assess systematic effects are only applicable to the analysis of the same reference material type or assume that some uncertainty components affecting evaluations are negligible or constant. This work presents detailed algorithms for the assessment of systematic effects, through the determination of recovery and the respective recovery uncertainty, applicable to the analysis of various independent reference materials, such as CRMs and spiked samples with native analyte. These algorithms are applicable to cases where native analyte and/or spiking values are associated with relevant and significantly different uncertainties allowing for a reliable assessment of systematic effects and measurement uncertainty for these complex cases. This methodology was successfully applied to the quantification of Na, K, Mg, Ca, Cr, Mn, Fe and Cu in water samples from two proficiency testing schemes, by ICP-OES, where recovery was estimated from the analysis of samples with different native concentrations and spiked at different levels. The relative expanded uncertainties of the measurement results ranged from 28.9 % to 3.9 % and are fit for the monitoring of environmental water samples in accordance with criteria set in the European Union legislation.
PubDate: 2017-11-18
DOI: 10.1007/s00769-017-1296-2

• Change of shift
• PubDate: 2017-11-10
DOI: 10.1007/s00769-017-1301-9

• Farewell
• Authors: H. Emons
PubDate: 2017-11-10
DOI: 10.1007/s00769-017-1300-x

• Certification for trace elements and methyl mercury mass fractions in
IAEA-456 marine sediment sample
• Authors: Emilia Vassileva; Sabine Azemard; Petko Mandjukov
Abstract: Abstract Marine sediment certified reference material (CRM), IAEA-456 was recently produced by the Environment Laboratories of the International Atomic Energy Agency (IAEA) and certified for trace elements and methyl mercury (CH3Hg). This paper presents the sample preparation methodology, material homogeneity and stability studies, evaluation of results from the characterisation campaign, the assignment of property values and their associated uncertainty. The reference values and associated expanded uncertainty for nine trace elements (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) and CH3Hg in marine sediment sample are established. The new CRM can be used for the development and validation of analytical methods, for the determination of trace elements and methyl mercury in sediments and also for quality assurance/quality control purposes.
PubDate: 2017-11-04
DOI: 10.1007/s00769-017-1297-1

• Congress, conferences, workshops and courses
• PubDate: 2017-11-02
DOI: 10.1007/s00769-017-1299-z

• Bayesian analysis of homogeneity studies in the production of reference
materials
• Authors: Adriaan M. H. van der Veen
Abstract: Abstract For almost two decades, the batch homogeneity in the production of reference materials has been evaluated using analysis of variance (ANOVA) to determine the between-bottle standard deviation. This approach replaced at that time the use of the F-test in ANOVA to determine whether the ratio of the mean squares $${MS}_{\mathrm {between}}/{MS}_{\mathrm {within}}$$ is statistically significant. Problems arise when $${MS}_{\mathrm {between}} < {MS}_{\mathrm {within}}$$ , because classical ANOVA provides a negative between-bottle variance, which is then often set to zero. By using a Bayesian hierarchical model, based on the same assumptions as traditional ANOVA, we show that even if $${MS}_{\mathrm {between}} < {MS}_{\mathrm {within}}$$ , there can be a relevant level of between-bottle inhomogeneity to account for. The Bayesian analysis produces a nonzero value for the between-bottle standard deviation, which dismisses the practice of setting this standard deviation to 0. At the same time, it dismisses the current guidance given in ISO Guide 35 under these circumstances. Finally, it is shown that traditional ANOVA, meta-analysis methods and Bayesian analysis give very similar answers as long as $${MS}_{\mathrm {between}} > {MS}_{\mathrm {within}}$$ , so there is no need to discourage using these methods in favour of a Bayesian analysis, provided that the repeatability of the measurement method used to conduct the between-bottle homogeneity study is sufficient to characterise the dispersion across the bottles (items) in a batch of a reference material.
PubDate: 2017-11-02
DOI: 10.1007/s00769-017-1292-6

• Laboratory capacity building through the use of metrologically traceable
reference values in proficiency testing programmes
• Authors: Robert Kaarls; Lindsey Mackay; Angela Samuel; Della Wai-mei Sin; Chuen-shing Mok; Yee-lok Wong; Yiu-chung Yip
Abstract: Abstract There is an increasing need for laboratory capacity building through the organisation of proficiency testing programmes with metrologically traceable reference values in the Asia-Pacific region. Stakeholders such as the regional metrology organisation, metrology institutes, and accreditation bodies are increasingly aware that consensus values of proficiency testing programmes could sometimes be significantly biased if the participating laboratories do not have clear understanding of their measurement capabilities and measurement uncertainties. In this article, we provide a review of the effectiveness of the use of reference values obtained from international comparisons among metrology institutes for performance evaluation in associated proficiency testing programmes. Important issues are discussed including determination of assigned values, the main methods employed by national metrology institutes/designated institutes and field analytical laboratories for analysis, estimation of measurement uncertainty, and guidance on analytical challenges presented by these studies. Application of measures such as appropriate matrix reference materials, particularly from incurred sources, for assessing extraction efficiencies and other measurement procedural issues, and proper knowledge of the uncertainty budgets are essential tools leading to effective and reliable measurements.
PubDate: 2017-10-25
DOI: 10.1007/s00769-017-1298-0

• Correction to: Uncertainty estimation of the determination of chemical sum
parameters in water
• Authors: Tony Venelinov
Abstract: Abstract Unfortunately, Eq. 3 was incorrectly presented in the original publication.
PubDate: 2017-10-10
DOI: 10.1007/s00769-017-1290-8

• The new International Standard ISO 17034: general requirements for the
competence of reference material producers
• Authors: Stefanie Trapmann; Angelique Botha; Thomas P. J. Linsinger; Sean Mac Curtain; Hendrik Emons
Abstract: Abstract The International Organization for Standardization (ISO) has published ISO 17034:2016 on the general requirements for the competence of reference material producers (RMPs). Previously, these requirements were addressed in ISO Guide 34:2009, originally developed by the ISO Committee on Reference Materials (ISO/REMCO). The need for an International Standard was triggered as several accreditation bodies could not accredit to a guide, at all, while in other countries ISO Guide 34 could only serve as accreditation standard in combination with ISO/IEC 17025. For the transformation into a conformity assessment standard of the ISO/IEC 17000 series, the ISO Committee on Conformity assessment (ISO/CASCO) and ISO/REMCO joined forces. A Joint Working Group, formed by experts and stakeholders from both committees, finalised the transformation within 2 years. During the transformation, the structure of ISO 17034 has been aligned with other ISO/IEC 17000 series standards and the content of ISO 17034 has been harmonised with the recent editions of other relevant ISO Guides. Requirements for the production of reference materials (RMs) were elaborated on more clearly in the new standard, specifying the requirements for (non-certified) reference materials and the additional requirements for certified reference materials. The new International Standard ISO 17034:2016 supersedes ISO Guide 34:2009.
PubDate: 2017-09-26
DOI: 10.1007/s00769-017-1285-5

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