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Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement
Journal Prestige (SJR): 0.316

Citation Impact (citeScore): 1
Number of Followers: 26

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

[2348 journals]

Correction to: Measurement uncertainty: requirements set in the
accreditation standards
- Authors: Kyriacos C. Tsimillis
  Pages: 253 - 253
  Abstract: Unfortunately, the references 12 and 13 were incorrectly published in the original publication. The correct references are:
  PubDate: 2018-08-01
  DOI: 10.1007/s00769-018-1323-y
  Issue No: Vol. 23, No. 4 (2018)
Application of post-column reaction GC for accurate and direct
determination of musty odor substances in standard solution
- Authors: Yuko Kitamaki; Naoki Saito; Masahiko Numata; Toshihide Ihara
  Abstract: By using post-column reaction GC, a method for accurate and direct characterization of musty odor substances (2-methylisoborneol and geosmin) in a candidate standard solution has been developed. Because the GC system gives a response depending on the number of carbon atoms constituting the organic compound by combustion and conversion to methane, naphthalene and diethyl phthalate, purity of which had been accurately assessed, were used as reference materials for calibration. To verify the method, concentrations of 2-methylisoborneol and geosmin in the sample determined by the method were compared with the concentrations calculated based on gravimetric mixing that is one of the general methods for the characterization of the organic standard solutions. The analytical results of each analyte obtained by the two methods agreed within a deviation of about 0.5 % or less.
  PubDate: 2018-08-06
  DOI: 10.1007/s00769-018-1338-4
Congresses, conferences, workshops and courses
- PubDate: 2018-07-24
  DOI: 10.1007/s00769-018-1340-x
Taking laboratory uncertainties into account in the Hampel estimator
- Abstract: According to ISO/IEC 17025:2017, testing and calibration laboratories should apply procedures for estimating measurement uncertainty. It would thus make sense to include these uncertainty estimates in the evaluation of laboratory performance in proficiency testing. According to ISO 13528:2015, submitted laboratory-specific uncertainties can be taken into account in the assessment of the performance of PT participants by means of \(\zeta\) (or \(E_{n}\) ) scores. It is important to note, however, that the laboratory uncertainties are not taken into account in the actual estimation of consensus means. In this paper, a proposal for a modification of the Hampel estimator is presented. In the original Hampel estimator, the laboratory weights are determined on the basis of a single reference quantity (e.g. \(\sigma_{\text{pt}}\) ). In the modified estimator, this single reference quantity is replaced by the laboratory-specific uncertainties. Thus, all available information is taken into consideration in the estimation of the consensus mean, ensuring a greater level of reliability. Moreover, since \(\sigma_{\text{pt}}\) is no longer needed in the computation of the consensus mean, the requirements regarding minimum participant numbers can be relaxed.
  PubDate: 2018-07-18
  DOI: 10.1007/s00769-018-1332-x
Evaluation of the reproducibility standard deviation in the pesticide
multi-residue methods on olive oil from past proficiency tests
- Authors: Patrizia Stefanelli; Tiziana Generali; Silvana Girolimetti; Danilo Attard Barbini
  Abstract: The data reported in the frame of proficiency testing (PT) exercises organized from 2007 to 2016 have been statistically re-evaluated using Algorithm A of the ISO 13528:2015, and the relative standard deviation for reproducibility of multi-residue methods for the determination of pesticides in olive oil was evaluated. Usually, the assigned between-laboratories variability in PTs on pesticide residues is fixed/set to 25 %. This value was compared to the calculated robust relative standard deviation (RRSD). A total of 1527 analytical results were collected in the ten PTs for the determination of pesticides in olive oil. An RRSD of 21 % was obtained, below the maximum value of 25 %. If all participants use the same analytical approach (e.g., multi-residue method and same instrumental technique), a lower value of the reproducibility standard deviation should be expecting. The QuEChERS method, coupled with LC–MS/MS and GC–MS/MS, has become an important methodology for the analysis of pesticide residues. This is due to its simplicity, the use of low quantities of acetonitrile, the possibility to analyze a large number of pesticides with fewer steps and high efficiency. This method may harmonize the future of pesticide residue analyses. Recently, it was successfully applied to the analysis of olive oil by 70 % of the laboratories participating to our last PT exercise. An expanded uncertainty of 50 % was systematically applied in Europe since 2006 for the analyses of pesticides; the use of the QuEChERS methodology may reduce to 40 %. This work could contribute to promote the comparability of measurements of pesticide residues in foodstuffs.
  PubDate: 2018-07-12
  DOI: 10.1007/s00769-018-1330-z
Experience of the implementation of EA-4/18
- Authors: Ian Mann
  Abstract: The standard ISO/IEC 17025 (sub-clause 5.9) requires that the validity of tests results is monitored by laboratories and one of the tools that can be used is the participation in proficiency testing (PT). To give guidance to accreditation bodies (ABs) on how to evaluate the level and frequency of participation in PT and to assist laboratories in determining their own levels and frequency of participation, a guidance document, EA-4/18 (Guidance on the level and frequency of proficiency testing participation), was established in 2010 by the European Cooperation for Accreditation (EA). There has been various feedback from the analytical community in Europe suggesting that some laboratories have experienced mixed messages from different assessors as to the level and frequency of PT participation required and that there may be a lack of harmonization between accreditation bodies. Given the concerns raised, the EEE-PT (EA-Eurachem-Eurolab) WG undertook a survey, with the support of the EA Laboratory committee, to ascertain the experience from the EA accreditation bodies with implementing the guidance. The survey was sent to the EA full and associate members. The outcome of the survey showed that EA-4/18 is implemented in a harmonized way throughout the accreditation bodies, but the concept included in EA-4/18 can be difficult to understand. As there are no specific indications in EA-4/18, on the level and frequency of participation, the implementation by each laboratory of the concept found in EA-4/18 can vary, even if the laboratories are active in the same field. In the same way, different assessors can have different views on the strategy established by the laboratory, therefore leading to the impression that the laboratories are treated differently. A majority of ABs wish to revise EA-4/18 as it is considered as a helpful guidance, but more clarification of the concept and additional examples should be included in the revised version, if EA decides to do so.
  PubDate: 2018-07-12
  DOI: 10.1007/s00769-018-1337-5
Evaluation of implementation of good quality management practices related
to the support processes in the laboratories of Moroccan faculties of
sciences and techniques
- Authors: Meriem Outaki; Ebrahim Kerak
  Abstract: The evaluation practices in the higher education in Morocco constitute a constitutional and legal requirement and also respond to the requirements of the national and international environment in perpetual evolution. To identify the level of application of good quality management practices related to the scientific research in Morocco, a questionnaire was administered to the research laboratories managers of the faculties of sciences and techniques on a national scale with a percentage of answer of 33 %. This paper concerns the evaluation of the implementation of theses good practices related to the support processes such as the management of material, human and informational resources. The results of this study showed the dissatisfaction of the majority of laboratories managers with regard to their availability. Besides, a minority of the laboratories respect practices related to the control of the function metrology and to the storage and the traceability of reagents. More than two-thirds managers asserted that their research teams are established on the basis of the affinities of the thematic of research of the researchers and are convinced of the homogeneity of the composition of the laboratory teams. This study emphasizes the necessity of increasing investment in the domain of scientific research to improve the availability of the resources. It is also necessary to sensitize the laboratory staff to the importance of the implementation and control of the metrology function to assure reliability of the research results.
  PubDate: 2018-07-10
  DOI: 10.1007/s00769-018-1336-6
Validation of an in-house measurement procedure for determination of
selected priority hazardous substances in water and estimation of
measurement uncertainty
- Authors: Marijana Kragulj Isakovski; Jelena Molnar Jazić; Snežana Maletić; Aleksandra Tubić; Jasmina Agbaba; Jelena Tričković; Božo Dalmacija
  Abstract: This study investigates measurement procedure validation for the determination of hexachlorobenzene, pentachlorobenzene and trifluralin as priority hazardous pesticides in water with suspended solids < 12 mg/L by liquid–liquid extraction with hexane and gas chromatography with electron capture detector analysis. Two water matrices were used: synthetic matrix and a natural matrix—Danube surface water. Limit of detection was in the range 2.2 ng/L–3.9 ng/L. Trueness expressed as recovery was determined at pesticide concentrations of 20 ng/L and 50 ng/L in both water matrices. The intermediate precision was determined as relative standard deviations (RSD) and represents an agreement between replicates. Trueness was 72 %–121 % with RSD < 20 %. Expanded uncertainty of measurement was similar for all compounds (33.3 %–37.5 %) with a 95 % confidence level, for coverage factor k = 2. The validity of the measurement procedure was confirmed by participation in a PT Scheme with satisfactory z -score smaller than 2. Based on these results, it can be concluded that this low-cost measurement procedure is fit for the intended use measurements.
  PubDate: 2018-07-07
  DOI: 10.1007/s00769-018-1334-8
Preparation of items for a textile proficiency testing scheme
- Authors: Juana Isabel Ferreiro López-Riobóo; Natalia Crespo González; Purificación López Mahía; Soledad Muniategui Lorenzo; Dario Prada Rodríguez
  Abstract: One of the fundamental stages in planning and developing any interlaboratory comparison is the selection and preparation of the test items to be distributed to the participants. In the case of compositional testing of textile materials, it is essential (1) to correctly identify the nature of the fibres which composes the fabric and (2) to check the homogeneity of the each test item. The Galician Laboratory of Consumer Products organized a proficiency testing (PT) in 2016 for textile fibres. Initial preparatory work was carried out with the assistance of the University of A Coruña, to identify the nature of the textile fibres using several complementary techniques specified in ISO/TR 11827 (e.g. optical microscopy, scanning electron microscopy, solubility tests and infrared spectroscopy). The fibres were compared with those from reference fabrics which were supplied by the Institute of Textile Research and Industrial Cooperation of Terrassa (INTEXTER). After the complete identification of the fibres, an assessment of homogeneity of the fabrics was performed according to the requirements in ISO 13528. Subsequently, five PT items were distributed and analysed according to the requirements set by ISO 1833 parts 3, 4, 7, 11 and 12, respectively. Eighteen laboratories from nine countries reported results, and the statistical treatment of results was performed according to ISO 13528. The assigned values were established by consensus, while the uncertainties were evaluated using the Naji Plot.
  PubDate: 2018-07-03
  DOI: 10.1007/s00769-018-1325-9
A fitness for purpose approach to validation and verification of
analytical measurements
- Authors: M. Alvarez-Prieto; J. Jiménez-Chacón
  Abstract: Validation (and in some extension verification) are concepts often applied to analytical procedures (or methods). The new edition of ISO/IEC 17025 clearly distinguishes between them. However, the established practice in analytical chemistry is not in harmony with the definitions given in the International Vocabulary of Metrology. It is stressed that both concepts should be applied to the analytical process (i.e., the measurement) instead of to the written analytical procedure (or method). Formal new definitions of basic and complementary metrological characteristics are given in order to properly understand the concepts of metrological requirements (MRs), verification and validation, and how they should be applied in practice. Also, validation is conceptually linked to the intended use of results, that is, to make the correct decision with a given high probability. To understand the rationale behind these concepts, a logical flow diagram is discussed. The way to compare basic metrological characteristics and the previously obtained ones for verification, as well as how to compare them with MRs for validation is discussed. Conversion of product characteristics into MRs plays an important role in this latter case. Some general guidelines on extension (and depth) of verification and validation are offered. Some of the discussed ideas could be applied in other branches of metrology.
  PubDate: 2018-07-03
  DOI: 10.1007/s00769-018-1331-y
Influence of probability distribution in measurement uncertainty of
plane-strain fracture toughness test
- Authors: Daniel Antonio Kapper Fabricio; Carla Schwengber ten Caten; Lisiane Trevisan; Afonso Reguly
  Abstract: The evaluation of measurement uncertainty by testing laboratories has a direct impact on the interpretation of the results. In several cases, it is recommended to determine the measurement uncertainty by the Monte Carlo method (MCM), which considers the propagation of distributions rather than the propagation of uncertainty. Measurement uncertainty of plane-strain fracture toughness KIC test was evaluated through the MCM and an examination of the influence of the probability distribution on the uncertainty values was performed through analysis of variance (ANOVA). In addition, results were compared to those obtained by the Guide to the Expression of Uncertainty in Measurement (GUM). Results demonstrate the importance of using the Monte Carlo method for the evaluation of measurement uncertainty and confirm that the probability distribution of input data has a significant influence on the expanded uncertainty values obtained for the plane-strain fracture toughness test.
  PubDate: 2018-07-02
  DOI: 10.1007/s00769-018-1326-8
Characterisation of folic acid by mass balance versus quantitative NMR
- Authors: Andrea Lodi; Cees-Jan Nap; Silvia Metzger-Maurer; Christelle Schwartzenberger
  Abstract: Two approaches were used to determine the mass fraction of a sample of folic acid, one indirect (mass balance) where the components other than folic acid were measured, and one direct, using quantitative nuclear magnetic resonance (qNMR). The procedures used for the mass balance were essentially those described in the European Pharmacopoeia monograph for folic acid. qNMR is a technique for quantifying the main component within an organic compound (Quantitative NMR (qNMR)—BIPM in https://www.bipm.org/en/bipm/chemistry/organic-analysis/qnmr/, Santosh and Raja in Trends Anal Chem 35:5–26, 2012), whereas mass balance quantifies its minor components. The results obtained with the two approaches are independent. In this study, their joint application generated information that was used in a more than complementary fashion. The mass balance characterisation, in particular the results obtained by liquid chromatography with ultraviolet detection (LC–UV), allowed to improve the accuracy of the qNMR result by subtracting the interfering contribution of a related structure impurity. On the other hand, qNMR enabled concluding that the non-uniform response of UV detection at a single wavelength was not critically biasing the LC–UV results. In the end, the mass fractions obtained by mass balance and qNMR were not that different. It is concluded that mass balance and qNMR may be not only complementary but also synergistic. It was also observed that access to monographs of the European Pharmacopoeia, when available, gives skilled analysts an important tool for improved substance characterisation.
  PubDate: 2018-06-28
  DOI: 10.1007/s00769-018-1327-7
Correction to: Motivations, benefits and challenges on ISO/IEC 17025
accreditation of higher education institution laboratories
- Authors: Inês Hexsel Grochau; Carla Schwengber ten Caten; Maria Madalena de Camargo Forte
  Abstract: Unfortunately, figure 3 was incorrectly published in the original publication and the correct version is updated here.
  PubDate: 2018-06-18
  DOI: 10.1007/s00769-018-1333-9
Results of the 16th proficiency test on the determination of pesticide
residues in olive oil
- Authors: Tiziana Generali; Patrizia Stefanelli; Silvana Girolimetti; Danilo Attard Barbini
  Abstract: The Italian National Reference Laboratory (NRL) for pesticide residues yearly organizes proficiency tests (PTs) on olive oil in cooperation with the International Olive Council, addressed to European laboratories (NRLs, official control laboratories, and private laboratories), involved in the National and European monitoring programs. The main aim of these PTs is to compare the performances of the laboratories in Mediterranean and European countries and to promote mutual acceptance of pesticide residue data regarding the analytical controls of olive oil. In this paper, a description of the last PT named COIPT-16 is presented. The test material consisted of a commercial olive oil spiked with six different pesticides. The assigned value of each analyte was determined as a consensus value based on the results of the participants calculated using Algorithm A of the ISO 13528:2015. As relative target standard deviation in the z score formula, the 25 % of the robust mean value was considered. The global performance of each participating laboratory was assessed by calculating the average of the squared z scores only for laboratories that have detected at least 80 % of the analytes present in sample achieving the sufficient scope as indicated in the initial protocol. Two compounds, alpha-endosulfan and beta-endosulfan have been analyzed again in this PTas in the previous PT to compare the performances of the laboratories whose supplied results both PTs. The quick, easy, cheap, effective, rugged, and safe methodology was used by the majority of laboratories corresponding to 64 % of participants.
  PubDate: 2018-06-14
  DOI: 10.1007/s00769-018-1329-5
Standardization and improvement program for creatinine measurement in
human serum
- Authors: H. Gasca-Aragon; M. Balderas-Escamilla; V. M. Serrano-Caballero; M. A. Avila-Calderon; A. G. Pabello-Poegner; R. Sierra-Amor; R. Ruiz-Arenas; A. M. Cueto-Manzano; L. Cortes-Sanabria; H. R. Martinez-Ramirez; G. Garcia-Garcia; M. Arce-Osuna; Y. Mitani-Nakanishi
  Abstract: Current practices, quality control systems and proficiency testing schemes in clinical laboratories are likely unable to detect intrinsic bias in the in vitro diagnostic kits for creatinine as characterized or applied. A standardization program for clinical laboratories to determine the concentration of creatinine in human serum prior to estimate the glomerular filtration rate (eGFR) was conducted by the Mexican Association for Prevention of Chronic Diseases (AMPEC) and CENAM in 2016. In this study, 21 public and private clinical laboratories participated voluntarily and contributed with results of 27 measurement methods. These results were used to build a set of specific bias models, respectively, and then applied by each laboratory to correct their new measurements. A two-stage study was conducted; the first stage consisted of a blind experiment using certified reference material (CRM) DMR-574a of creatinine in human serum at three levels. The participating laboratories measured all three CRMs samples under a proficiency testing protocol using their routine methods. Linear regression with error in variables was applied to modeling the participants’ measurement method. In the second stage, each laboratory measured the concentration of creatinine in serum in approximately 100 samples from ambulatory patients, obtaining a total sample of 2416 measurements; subsequently, eGFR was calculated. In most of the participating laboratories (97 %), significant creatinine measurement bias was observed. Diagnosis based only on the concentration of creatinine in serum showed that: 72 % of the cases were correct, 23 % underestimated the eGFR and 5 % overestimated the eGFR. Bias is induced in the eGFR if no correction is made.
  PubDate: 2018-06-12
  DOI: 10.1007/s00769-018-1316-x
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
Congresses, conferences, workshops and courses
- PubDate: 2018-06-04
  DOI: 10.1007/s00769-018-1324-x
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
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