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1.
This article briefly describes research on the development of primary reference gases and the traceability system of gas measurement
at the National Research Center for Certified Reference Materials, China. 相似文献
2.
X. R. Pan 《Accreditation and quality assurance》1996,1(4):181-185
Traceability is an essential property of a measurement result. However, it is recognized that the results of chemical measurements
can be lacking in this property. In this paper we try to show how to understand and establish traceability in chemical measurement.
The traceability connotation and the necessity of tracing back to SI units are described by means of comparability well-known.
The roles and interrelationships of quality assurance, accreditation, calibration, reference material, analytical method,
comparison and uncertainty in establishing traceability are explained with the aid of a block diagram. The paper also includes
diagrams illustrating the Chinese situation and experience of establishing traceability for chemical measurement in China. 相似文献
3.
N. Sagara T. Kondo M. Saeki I. Inamoto K. Kakita 《Accreditation and quality assurance》1997,2(3):120-129
ISO 9000 series strictly requires traceability to national or international measurement standards. It is becoming more necessary
to make clear the concept of traceability of measurement standards with respect to chemical composition and to accredit the
reference material producers. In Japan, the accreditation system for reference material producers is considered to satisfy
the requirement of ISO Guide 34, ISO 9000 series and ISO/IEC Guide 25, while the producer fulfills the concept of traceability
of measurement standards. This paper describes the production of iron and steel reference materials in Japan relating to the
international standardization of methods (written standards) and accreditation of reference material producers.
Received: 11 October 1996 Accepted: 5 December 1996 相似文献
4.
Traceability to the System International (SI) is an important prerequisite for international comparability and uniformity
of chemical measurements to ensure mutual recognition of the results. In theory, all measurements can be traced back to the
seven base units of the SI. Although the traceability system works well for most physical measurements, in many analytical
and in some spectrophotometric measurements this system is not satisfactory. This paper describes the particular and practical
problems and the contribution of the Romanian National Institute of Metrology in this field. The paper discusses the following
concepts: clearly defined targets in the form of requirement specification, knowledge of trueness and/or measurement uncertainty,
and traceability through an unbroken chain of calibration to primary standards. Traceability and uncertainty being two concepts
inherently coupled, two examples of assessment of the uncertainty of measurement results are given for two spectrophotometric
methods currently used in chemical laboratories.
Received: 17 July 1996 Accepted: 2 September 1996 相似文献
5.
J. Yoshinaga Y. Shibata T. Horiguchi M. Morita 《Accreditation and quality assurance》1997,2(3):154-156
The National Institute for Environmental Studies (NIES) recently prepared two candidate certified reference materials (CRMs)
for arsenicals to meet the growing demand for the quality assurance of arsenic speciation analysis. The NIES candidate CRM
No. 14 Brown Alga was prepared from Hijiki seaweed for the certification of inorganic arsenic content, and No. 15 Scallop was prepared from adductor muscle of scallop
for the certification of arsenobetaine content. The preparation of the candidate CRMs is briefly described. Cooperative analyses
for total arsenic content of the candidate CRMs have been underway. The preliminary speciation analysis at NIES revealed difficulty
in establishing suitable conditions for extracting arsenic species from the materials. Chromatograms of arsenic species by
a high performance liquid chromatography-inductively coupled plasma mass spectrometric detection system are presented to provide
information about arsenic species present in these candidate CRMs. 相似文献
6.
Since the implementation of ISO/IEC 17025 in 2002, all accredited laboratories (at the least) need to establish traceability in all their tests and calibration methods. Traceabilty, though well understood in the calibration field (through an unbroken chain of comparisons to the International System of Units —SI), is less straight forward and not so well understood in the testing laboratories. Traceability in analytical and biological testing is found through the use of reference materials, and the validated steps of a test method. This article describes the possibilities to comply with the traceability requirement of ISO/IEC 17025 in testing laboratories , when certified reference materials are unavailable.Presented at the Second International Conference on Metrology—Trends and Applications in Calibration and Testing Laboratories, 4–6 November, 2003, Eilat, Israel 相似文献
7.
Ian Robert Juniper 《Accreditation and quality assurance》1998,3(2):79-82
Certified reference materials are widely used for the calibration of measuring equipment and for the evaluation or validation
of measurement procedures. The use of reference materials makes possible the transfer of the values of measured or assigned
quantities between testing, analytical and measurement laboratories, both nationally and internationally. There is an increasing
number of reference materials producers in other countries, and a demonstration of their scientific and technical competence
is now more widely considered to be a basic requirement for ensuring the quality of reference materials. This article outlines
recent activities by international bodies and their culmination in a scheme of accreditation of certifiers of reference materials
which has been developed by the National Association of Testing Authorities, Australia (NATA). 相似文献
8.
Adriaan M. H. van der Veen Thomas P. J. Linsinger Heinz Schimmel Andree Lamberty Jean Pauwels 《Accreditation and quality assurance》2001,6(7):290-294
The main objective of the certification of a reference material is to determine its property values including their uncertainty.
In the previous parts of this series, the basis for the evaluation of measurement uncertainty of the property values has been
examined, including the conversion of homogeneity and stability study data into standard uncertainties. In this final part,
the determination of the property values and the modelling of the certification process is discussed. It is noted that the
characterisation of a reference material can be modelled in some cases using analysis of variance statistics, but a more generally
applicable model can be developed based on χ2-fitting. Furthermore, it is concluded that there is an advantage in using absolute standard uncertainties instead of relative
ones when modelling the certification process.
Received: 14 October 2000 Accepted: 21 January 2001 相似文献
9.
The present situation of Japanese certified reference materials registered in the COMAR database 总被引:1,自引:0,他引:1
In the field of reference materials, COMAR (Code d'Indexation des Matériaux de Référence) is now internationally known as
a reliable directory. In order to improve the quality of COMAR, a document which covers general requirements for the registration
of reference material has recently been adopted by the Japanese coding centre, NITE. This paper describes the general requirements
for reference materials and the current status of the COMAR database coded by the National Institute of Technology and Evaluation
(NITE), Japan. The concept of the requirements is fundamentally based on the ISO Guides 30, 31, 33, 34 and 35. Certifications
of reference materials are divided into the following three categories in the newly adopted document.
1. Certifications based on the results of interlaboratory comparisons
2. Certifications in accordance with the Measurement Law
3. Certifications in accordance with the measurement results of national institutions
An example of an uncertainty evaluation is also presented in the paper.
Received: 14 October 1996 Accepted: 3 December 1996 相似文献
10.
Brian Belanger 《Accreditation and quality assurance》2001,6(3):100-102
During the last quarter of the twentieth century, The United States National Bureau of Standards (NBS), later the National
Institute of Standards and Technology (NIST), introduced a measurement quality control concept called ”measurement assurance,”
and developed measurement assurance programs, or MAPs, for high-level calibration processes. The measurement assurance approach
has, over time, become increasingly popular in the metrology community, and in recent years has become well accepted both
inside and, to some extent, outside the United States as a rigorous way to ensure the quality of calibrations. The concept
has also found application in defining traceability to national standards. This paper traces the history of the measurement
assurance concept.
Received: 23 October 2000 Accepted: 2 November 2000 相似文献
11.
P. De Bièvre Robert Kaarls H. Steffen Peiser S. D. Rasberry William P. Reed 《Accreditation and quality assurance》1997,2(6):270-274
In continuing their attempt to bring general issues concerned with trustworthy chemical measurements to review and international
discussion, the authors propose basic aims and requirements for protocols of chemical-measurement procedures with traceability
to the SI or, where this is not possible, to units of internationally recognized measurement scales. Documents describing
such protocols could be useful in science, technology, law, or trade. Concepts and definitions for protocols have been introduced
in Part I of this contribution. Part II here deals with the development and application of protocols for intended in-laboratory,
commercial, national, or international recognition. Protocols deal with measurement methods, instrumentation, and the estimation
of uncertainties from all possible sources of measurement errors. Uncertainties define the quality of all links in a traceability
chain starting from the value of a measurand in a sample, often through a certified value in a reference material, either
to the SI, or – if this is not possible – to a value on a suitable, internationally agreed measurement scale. A protocol may
concern itself with the complex interplay between uncertainties, tolerances, and any limit values introduced by the set aims
of specific measurements.
Received: 23 April 1997 Accepted: 27 April 1997 相似文献
12.
K. Heydorn 《Accreditation and quality assurance》1998,3(3):111-114
Stability tests are carried out on candidate reference materials in order to ascertain that the certification values continue
to be valid a reasonable time after completion of the certification analysis. These tests are also used for recommending storage
conditions, as well as the duration of storage before certification values need be rechecked. BCR (Community Bureau of Reference)
reference materials do not normally have an expiry date, but rely on stability monitoring throughout the lifetime of the certified
material. The 1997 version of the BCR Guidelines for the production and certification of reference materials does, however,
take into account the necessity of limiting the validity of a certification, when degradation of the material during storage
cannot be ignored. This paper discusses an example of significant degradation taking place between the time of completion
of the certification analysis and the issue of a formal certificate. Various options are presented together with an account
of their influence on the certified values and their uncertainties.
Received: 3 October 1997 · Accepted: 3 November 1997 相似文献
13.
I. Kuselman Alexander Weisman Wolfhard Wegscheider 《Accreditation and quality assurance》2002,7(3):122-124
The traceability of in-house reference materials (IHRM) is discussed. It is shown that a systematic error in results of a
measured value, specific to a measurement method or to a laboratory developing an IHRM, can be overcome if a comparative approach
to IHRM characterization is used. A traceability chain of the value carried by the IHRM to the value carried by the reference
material with higher metrological status and sufficiently similar matrix (for example, a certified reference material – CRM
according to ISO Guide 30) is helpful in such a case. The chain is realized when the IHRM samples are analysed simultaneously
with the CRM samples under the same conditions. This and other traceability chains necessary for the IHRM development are
examined as the measurement information sources. 相似文献
14.
15.
M. Buzoianu 《Accreditation and quality assurance》2000,5(4):142-150
The basic concepts of traceability as they are defined by the Comité Consultatif pour la Quantité de Matière (CCQM) are difficult
to apply to some chemical results. For instance, for some environments or chemical analyses measurement results are expressed
in conventional units. Such units are realized on conventional scales relying on two fundamental pillars: reference materials
and standard specification. The octane number of fuel or water turbidity measurements are typical examples of such units.
Traceability concepts are discussed in terms of their practical applicability for turbidimetric analysis. Some outcomes on
the validation of the metrological performance of turbidimeters and the comparability of turbidity measurement results are
also presented.
Received: 8 June 1999 / Accepted: 13 December 1999 相似文献
16.
Since the uncertainty of each link in the traceability chain (measuring analytical instrument, reference material or other
measurement standard) changes over the course of time, the chain lifetime is limited. The lifetime in chemical analysis is
dependent on the calibration intervals of the measuring equipment and the shelf-life of the certified reference materials
(CRMs) used for the calibration of the equipment. It is shown that the ordinary least squares technique, used for treatment
of the calibration data, is correct only when uncertainties in the certified values of the measurement standards or CRMs are
negligible. If these uncertainties increase (for example, close to the end of the calibration interval or shelf-life), they
are able to influence significantly the calibration and measurement results. In such cases regression analysis of the calibration
data should take into account that not only the response values are subjects to errors, but also the certified values. As
an end-point criterion of the traceability chain destruction, the requirement that the uncertainty of a measurement standard
should be a source of less then one-third of the uncertainty in the measurement result is applicable. An example from analytical
practice based on the data of interlaboratory comparisons of ethanol determination in beer is discussed.
Received: 5 October 2000 Accepted: 3 December 2000 相似文献
17.
M. Kubota K. Kato A. Hioki H. Iijima Y. Matsumoto 《Accreditation and quality assurance》1997,2(3):130-136
Analytical instruments used for measurements of air and water pollution are calibrated by using reference materials such
as standard gases and standard solutions. In Japan, since the middle of the 1970s, those reference materials which are traceable
to the national standards maintained at national research institutes have been supplied to users by reference material producers.
In order to establish the primary standards and to secure the traceability from the working standards to the national ones,
various analytical methods such as coulometric, titrimetric and gravimetric analyses for purity determination and highly sensitive
atomic spectrometry for trace analysis have been developed as the primary methods and reference methods. The Japanese Measurement
Law, revised in 1992, has introduced a new traceability system in which a public organization, a "designated calibration body",
can also prepare and maintain the national standards under the advice and instruction of national research institutes. The
designated calibration body can provide calibration services to reference material producers (accredited calibration bodies)
by using the national standards. The reference materials supplied in conformity with the traceability system include standard
gases, pH standard solutions, metal standard solutions and non-metal ion standard solutions.
Received: 4 October 1996 Accepted: 2 December 1996 相似文献
18.
Application of isotope dilution mass spectrometry to research of certified reference materials 总被引:2,自引:0,他引:2
Mo-tian Zhao J. Wang Baikeng Lu Jianmin Ji Yanjuan Zhang 《Accreditation and quality assurance》2002,7(3):111-114
This paper briefly describes the method and applications of isotope dilution mass spectrometry(IDMS). Primary standard solutions
with various natural isotope abundances were used to certify the concentration of enriched isotope solutions by IDMS. Then
these enriched isotopes were used to certify unknown samples by IDMS. Li, K, Mg, Fe, Cu, Ni, Cd, Mo, Pb, etc in CRMs were
certified and very good results were obtained in three international comparisons by IDMS.
Received: 15 June 2000 Accepted: 26 October 2001 相似文献
19.
P. De Bièvre 《Accreditation and quality assurance》2000,5(6):224-230
Traceability is a property of the result of a measurement. Since values carried by (reference) materials must also have been
obtained, of necessity, by measurement, the definition of traceability also applies to reference materials. It is extremely
helpful to give the traceability (of the origin) of a reference material a separate name, i.e. 'trackability'. An analysis
of the function of values carried by reference materials, shows that they can fulfill different functions, depending on the
intended use. One of the functions located outside the traceability chain – and hence not very relevant for establishing traceability
– is evaluating the approximate size of the uncertainty of the measurement of an unknown sample by performing a similar measurement
on a reference material, used as a 'simulated sample'. Another function is located inside the traceability chain, where the
reference material is used as an added 'internal standard'. Then, the value carried by the reference material is essential
for establishing the traceability of the measured value of an unknown sample. In the latter application, the reference material
acts as an 'amount standard' (the certified value for amount is used).
Received: 11 November 1999 / Accepted: 24 February 2000 相似文献
20.
P. Fisicaro R. Champion G. Labarraque B. Lalere T. Mace C. Sutour 《Accreditation and quality assurance》2008,13(7):367-372
LNE is actively involved in the development of reference procedures in the domains of organic and inorganic chemistry and
in gas analysis. Moreover, production of certified reference materials (CRMs), certification of calibration standards, and
providing reference values for proficiency testing schemes (PTS) are fields well settled to ensure the traceability of measurements
in environmental monitoring. The paper presents some representative examples of these activities recently realised in our
laboratory.
Presented at BERM-11, October 2007, Tsukuba, Japan. 相似文献