JournalTOCs

Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement
Journal Prestige (SJR): 0.378
Citation Impact (citeScore): 30
Number of Followers: 26

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0949-1775 - ISSN (Online) 1432-0517
Published by Springer-Verlag

[2350 journals]

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
  Pages: 57 - 71
  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: 2018-04-01
  DOI: 10.1007/s00769-017-1296-2
  Issue No: Vol. 23, No. 2 (2018)
Measurement uncertainty: requirements set in the accreditation standards
- Authors: Kyriacos C. Tsimillis
  Pages: 109 - 114
  Abstract: Measurement uncertainty is of high importance to all testing and calibration laboratories and those involved in sampling activities. Its evaluation requires good understanding of the method implemented and realisation of all factors contributing to it. It is required that the users of the results fully understand the meaning of uncertainty stated on test reports and calibration certificates and, when needed, ask for clarifications. Laboratories, both the accredited ones and those being prepared towards their accreditation, need to take this into account when evaluating the uncertainty of their results. Competent authorities need to consider the stated uncertainty to compare the result with a legislative limit. The producer can decide on adjustments needed. The consumer may find it more difficult to understand how this “uncertain component” of the results could affect their health, safety or economic rights. This article describes the relevant requirements of the accreditation standards referring both to testing and calibration laboratories and to proficiency testing and reference material producers. Further to this, the article explains why all these factors have to be considered by a laboratory.
  PubDate: 2018-04-01
  DOI: 10.1007/s00769-018-1310-3
  Issue No: Vol. 23, No. 2 (2018)
Occurrence of nitrate in vegetables and dietary exposure assessment for
the Cypriot adolescent consumers
- Authors: Georgios Stavroulakis; Demetris Kafouris; Maria Christofidou; Lefkios Paikousis; Eftychia Christou; Maro Christodoulidou; Popi Kanari; Eleni Ioannou-Kakouri
  Pages: 115 - 122
  Abstract: In this study, a simple, rapid and sensitive ion chromatography method was used for the determination of mass fraction nitrate (mg kg−1) in 396 samples of vegetables. The method performance characteristics were determined after spiking blank samples. The mean recoveries in vegetables ranged from 94.0 % to 108.7 %. Limits of detection and quantification were 10 mg kg−1 and 30 mg kg−1, respectively. The results showed the mass fraction nitrate in vegetables was in the range of 10 mg kg−1–5619 mg kg−1. Leafy, root and stem vegetables, and herbs were the most contaminated, compared to other vegetables. Approximately 87 % of the samples were contaminated with nitrate; however, none of the samples analyzed was above the maximum limits for nitrate in vegetables. The dietary nitrate intake through consumption of vegetables was estimated for the adolescent population in Cyprus. The mean and 95th percentile intake values, based on median nitrate concentrations, were 1.12 kg d−1 and 3.42 mg kg−1 d−1, respectively. A small percentage (3.3 %) of the adolescent population had a nitrate intake above the Acceptable Daily Intake (3.7 mg kg−1 d−1). Lettuce and other leafy vegetables (spinach, rucola, purslane, beet leaves) contributed nearly 60 % to the overall nitrate exposure (mg kg−1 d−1).
  PubDate: 2018-04-01
  DOI: 10.1007/s00769-018-1311-2
  Issue No: Vol. 23, No. 2 (2018)
Congresses, conferences, workshops and courses
- Pages: 123 - 123
  PubDate: 2018-04-01
  DOI: 10.1007/s00769-018-1314-z
  Issue No: Vol. 23, No. 2 (2018)
Accurate determination of formaldehyde amount fraction in cylinders using
mixtures of primary standards of formaldehyde in nitrogen prepared by a
gravimetric permeation method
- Abstract: A reliable method for the quantification of formaldehyde (HCHO) amount fractions is required, because the results of comparisons between individual techniques used for the quantification of HCHO amount fractions often disagree owing to unknown causes. One reliable method comprises the quantification of HCHO using working gas standards in which the HCHO amount fraction is linked to the International System of Units (SI). In this work, the SI traceability of HCHO amount fractions in mixtures of commercial HCHO in nitrogen in cylinders used as working gas standards was established by calibrating them against primary gas standard mixtures (mixtures of HCHO in N2), which were prepared by a permeation method and were traceable to SI. The expanded relative uncertainties (k = 2) of the amount fractions in the primary gas standard mixtures were less than 0.6 %. The quantitative values of the amount fractions in the working gas standards had relative expanded uncertainties (k = 2) of 0.7 %–0.9 %.
  PubDate: 2018-06-06
  DOI: 10.1007/s00769-018-1321-0
Validation guidelines for PCR workflows in bioterrorism preparedness, food
safety and forensics
- Authors: Johannes Hedman; Moa Lavander; Emelie Näslund Salomonsson; Tomas Jinnerot; Lina Boiso; Bertil Magnusson; Peter Rådström
  Abstract: The polymerase chain reaction (PCR) is the backbone of contemporary DNA/RNA analysis, ideally enabling detection of one or just a few target molecules. However, when analysing food or forensic samples the analytical procedure is often challenged by low amounts of poor quality template molecules and complex matrices. Applying optimised and validated methods in all steps of the analysis workflow, i.e. sampling, sample treatment, DNA/RNA extraction and PCR (including reverse transcription for RNA analysis), is thus necessary to ensure the reliability of analysis. In this paper, we describe how in-house validation can be performed for the different modules of the diagnostic PCR process, providing practical examples as tools for laboratories in their planning of validation studies. The focus is analysis of heterogeneous samples with interfering matrices, with relevance in food testing, forensic DNA analysis, bioterrorism preparedness and veterinary medicine. Our objective is to enable rational in-house validation for reliable and swift quality assurance when results are urgent, for example in the event of a crisis such as a foodborne outbreak or a crime requiring the analysis of a large number of diverse samples. To that end, we explain the performance characteristics associated with method validation from a PCR and biological sample matrix perspective and suggest which characteristics to investigate depending on the type of method to be validated. Also, we include a modular approach to validation within the PCR workflow, aiming at efficient validation and a flexible use of methods.
  PubDate: 2018-06-05
  DOI: 10.1007/s00769-018-1319-7
Congresses, conferences, workshops and courses
- PubDate: 2018-06-04
  DOI: 10.1007/s00769-018-1324-x
Correction to: Measurement uncertainty: requirements set in the
accreditation standards
- Abstract: Unfortunately, the references 12 and 13 were incorrectly published in the original publication. The correct references are:
  PubDate: 2018-05-30
  DOI: 10.1007/s00769-018-1323-y
Motivations, benefits and challenges on ISO/IEC 17025 accreditation of
higher education institution laboratories
- Abstract: Accreditation of laboratories from higher education institutions (HEI) according to ISO/IEC 17025 contributes to meeting national regulatory requirements and to the involvement of countries in foreign trade. Additionally, these laboratories can benefit from the introduction of quality concepts and practices. Worldwide, testing and calibration laboratories from HEI face several challenges toward accreditation. This paper presents and comments on the characteristics, motivations, benefits and challenges toward accreditation of HEI laboratories. Responses to questionnaires sent to accredited HEI laboratories in the American continent showed that the vast majority undertakes tests for external clients, uses standardized methods and performs tests other than those accredited. Institutional decisions, external clients and regulatory requirements were the main motivators for accreditation. Lack of financial resources and lack of personnel were considered the main difficulties, while a preexisting laboratory structure and a motivated staff, the main facilitators toward accreditation. The resulting data allow a better understanding of the characteristics and difficulties of these laboratories. Additionally, this paper aims the identification of strategies to overcome problems faced by laboratories in HEI and research institutes, in order to promote the increase of their accreditation globally.
  PubDate: 2018-05-25
  DOI: 10.1007/s00769-018-1317-9
Changes to proficiency testing in developing countries over the last
10 years
- Abstract: Participation in proficiency testing schemes is necessary and beneficial for all testing laboratories across the world. Laboratories in developing countries face particular challenges in this context. These have been discussed during the last 10 years at various international workshops organized by Eurachem. An online survey on the developments during this period has been performed, and the results are presented here. Affordability and availability of proficiency tests as well as transport and customs issues are still the major problems. Installation of national or regional schemes could solve some of these problems, but their sustainability is a challenge. Finally, the author’s personal opinion on the conclusions that can be drawn from the results of the survey is given.
  PubDate: 2018-05-23
  DOI: 10.1007/s00769-018-1322-z
Improved continuous packaging method of the certified reference material
for low water content in liquid
- Authors: Ting Wang; Haifeng Wang; Heng Su; Xingliang Huang; Xiaoping Song; Kang Ma
  Abstract: Certified reference materials (CRMs) for water content are used to calibrate or validate Karl Fischer titrations for accuracy and consistency. Ampoules of CRMs with low water content are typically prepared by a continuous packaging method, and the water content may decrease or increase over time as the CRM is dispensed. In the present study, we measured the water activities of solutions of water in xylene with various water contents. We found the equilibrated humidity of the solution increased as the water content increased. An improved continuous packaging method using a pre-equilibrated bottle was employed to prepare the CRM of xylene for water content. The average water contents of the solutions dispensed into the ampoules are 73 mg/kg (relative standard deviation 1.6 %) and 221 mg/kg (relative standard deviation 0.4 %). There was no obvious shift in the water contents in ampoules of these CRMs over time. Analysis of variance indicated that the water contents of these two CRM candidates in ampoules were homogeneous, and the relative uncertainties in the water contents because of the inhomogeneity were 1.2 and 0.3 % for the low and high water contents, respectively. This simple method dispenses xylene under its equilibrated humidity condition, which reduces the exchange of water between the solution and headspace. This method will be useful for the preparation of CRMs for low water content.
  PubDate: 2018-04-25
  DOI: 10.1007/s00769-018-1318-8
Interferences, a neglected error source for clinical assays
- Authors: Jan S. Krouwer
  Abstract: In clinical assays, interfering substances can cause large errors, which in turn can result in severe patient harm. Yet, perhaps because such errors are rare, not much attention is devoted to interferences. This is evident in specifications, which often focus on most, but not all of the results. Methods such as total error analysis, six sigma, and measurement uncertainty intervals are all useful but fail to properly account for interferences, and the Clinical Laboratory Standards Institute standard on interferences has misleading reporting advice. Suggestions are given to improve specifications, protocols, analyses, and reporting methods.
  PubDate: 2018-04-20
  DOI: 10.1007/s00769-018-1315-y
Report on the 40th meeting of ISO/REMCO
- Authors: Angelique Botha; John Hammond; Hendrik Emons; Stéphane Sauvage
  Abstract: The 40th meeting of the Reference Material Committee of ISO, ISO/REMCO, was held in Berlin, Germany, from 26 to 29 June 2017, and was hosted by the Federal Institute for Materials Research and Testing (BAM) and the German Institute for Standardization (DIN). This report details and summarizes the discussions and findings of the associated group sessions, and meetings.
  PubDate: 2018-04-03
  DOI: 10.1007/s00769-018-1313-0
Definition of reference values in synthetic emission monitoring bench
loops
- Authors: D. Cipriano; L. Fialdini
  Abstract: Proficiency tests (PTs) are widely used in order to certify capabilities of laboratories, determine and validate uncertainties and validate methods. One of the major difficulties in emission monitoring PTs is due to realisation of a stable and ‘metrological correct’ gas matrix, and, since now, the most common approach is based on emissions gases taken from industrial boilers, from which, therefore, the composition is ‘metrological’ unknown, or on ambient air added with compounds of interest, but, in this case, the chemical behaviour of the matrix may be different from real cases. Synthetic emissions loops give the possibility to fill this gap, but require particular protocols for definition of reference values and their uncertainties. One solution, adopted on the facility realised at RSE research centre in Italy, is shown.
  PubDate: 2018-03-27
  DOI: 10.1007/s00769-018-1312-1
Discussion on homogeneity assessment of reference materials based on
uncertainty comparison method
- Authors: Chonghua Liu; Zhiyong Ding; Yong Tian; Lezhou Yi; Ningshan Huang
  Abstract: An uncertainty comparison method is proposed to assess the homogeneity of reference materials. The method compares “standard uncertainty associated with between-unit variability” (ubb) with “target standard uncertainty” (utrg) or “measurement uncertainty” (umeas) to solve the problems in assessing homogeneity of reference materials. Methods for the calculation of ubb, utrg and umeas as well as criterion for the quantitative judgment of sample homogeneity are introduced. When ubb ≤ 0.3utrg, it shows the sample is considered to be homogeneous; when 0.3utrg < ubb ≤ 0.7utrg, the sample is considered to be sufficiently homogeneous for the intended use; and when ubb > 0.7utrg, the sample is considered to be inhomogeneous. The uncertainty comparison method is compared with the F test method and shown to be more objective for the assessment of the homogeneity of certified reference materials for the chemical testing of toys.
  PubDate: 2018-02-02
  DOI: 10.1007/s00769-017-1308-2
Congresses, conferences, workshops and courses
- PubDate: 2018-02-01
  DOI: 10.1007/s00769-018-1309-9
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: 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: 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
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: 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: 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