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1.
An Ultra-Clean Chemical Laboratory (UCCL) has been built at IRMM to allow reliable, contamination-free chemical treatment of samples prior to inorganic elemental or isotopic analysis. The concept is intended to guarantee a dust-free environment as well as resistance to corrosion even if hot concentrated mixtures of acids are continuously used, thus establishing not a clean or dust-free room but a clean laboratory. The excellent air quality is demonstrated both by particle measurements and the analysis of acids purified by subboiling distillation in the UCCL.  相似文献   

2.
 An Ultra-Clean Chemical Laboratory (UCCL) has been built at IRMM to allow reliable, contamination-free chemical treatment of samples prior to inorganic elemental or isotopic analysis. The concept is intended to guarantee a dust-free environment as well as resistance to corrosion even if hot concentrated mixtures of acids are continuously used, thus establishing not a clean or dust-free room but a clean laboratory. The excellent air quality is demonstrated both by particle measurements and the analysis of acids purified by subboiling distillation in the UCCL. Received: 1 March 1996/Accepted: 16 April 1996  相似文献   

3.
This paper discusses the basis and historical development of the traceability chain for pH. The quantity pH, first introduced in 1909, is among the most frequently measured analytical quantities. The practical measurement of the pH value of a sample is inexpensive, easy to perform, and yields a rapid result. However, the problems posed by the traceability of pH are not easy to solve. Most pH measurements are performed by potentiometry, using a glass electrode as the pH sensor. Such pH electrodes must be calibrated at regular intervals. Confidence in the reliability of pH measurements requires establishment of a metrological hierarchy including an uncertainty budget for calibration that links the pH measured in the sample to an internationally agreed and stated reference. For pH, this reference is the primary measurement of pH. A traceability chain can be established that links field measurements of pH to primary buffer solutions that are certified using this primary method. This allows the user in the field to estimate the measurement uncertainty of the measured pH data. As the realization of the primary measurement is sophisticated and time-consuming, primary standards are generally realized at national metrology institutes. A number of potentiometric methods are suitable for the determination of the pH of reference buffer solutions by comparison with the primary standard buffers. The choice between the methods should be made according to the uncertainty required for the application. For reference buffer solutions that have the same nominal composition as the primary standard, the differential potentiometric cell, often called the Baucke cell, is recommended.  相似文献   

4.
The potential approaches for third-party assessment of reference material producers are revisited and the activities of the Reference Materials (RM) Unit of the Institute for Reference Materials and Measurements (IRMM) to obtain accreditation to ISO Guide 34 and ISO 17025 are described. Accreditation was related to the Unit as all matrix RM activities of the institute are concentrated there. A management system was established that allows sufficient flexibility to be applicable to a wide range of RMs while being precise enough to ensure compliance with ISO Guides 30, 31 and especially 34 and 35. Accreditation was achieved in 2004 with independent scopes for testing and RM production and was confirmed and extended in 2005. The key aspects of the RM Unit's management system for RM production are presented. Presented at BERM-10, April 2006, Charleston, SC, USA  相似文献   

5.
It is now over two years since ISO/IEC 17025 General requirements for the competence of testing and calibration laboratories was published. The standard places increased emphasis on the demonstration of traceability of measurements made by laboratories. In the areas of chemical and biological metrology, the introduction of this standard has brought new challenges for laboratories to grapple with. This paper will examine the requirements regarding traceability for chemical and biological measurements, with specific reference to the use of reference materials by laboratories. This will be explored from the perspective of both accreditation bodies and a laboratory which is both a user and producer of certified reference materials. Moreover, the paper will describe mechanisms that are being used to improve the use of reference materials by accredited laboratories and hence the traceability of measurements. Finally the role of accreditation programs for reference material producers in assisting with this aspect will be examined.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.Presented at BERM-9—Ninth International Symposium on Biological and Environmental Reference Materials, June 15–19, 2003 Berlin, Germany.  相似文献   

6.
Nowadays, within the Russian system of higher education there are two subsystems working fairly independently. One is mass higher education, and other is fundamental (quality) education. The educational reform which has been underway since the mid-1990s only makes worse the situation. Every year higher school teachers note a decrease of the quality of applicants and first-year students, gaps in their knowledge of chemistry, mathematics, and other disciplines. Under such conditions, universities should provide themselves with a corpse of the adequately prepared applicants. What can be done in order to preserve traditions of the Russian fundamental university education? First of all, quality textbooks for school pupils and applicants can be written and published. Further, connections between higher education institutions and secondary school in various regions of the country can be established and developed. Another very important task consists in organizing and conducting science Olympiads for schoolchildren and applicants. All these activities are being undertaken now by the Moscow State University.  相似文献   

7.
 The paper covers the main principles of setting up and the function of the Russian system of metrological assurance of analytical measurements for the production of light alloys and superalloys. Received: 20 October 1998 / Accepted: 9 November 1998  相似文献   

8.
The Molecular Sciences Software Institute (MolSSI) is an National Science Foundation (NSF) funded institute that focuses on improving software, education, and training in the computational molecular sciences. Through a collaboration with the Molecular Education and Research Consortium in Undergraduate computational chemistRY (MERCURY), the MolSSI has developed resources for undergraduate and other early career students to lay an educational foundation for the next generation of computational molecular scientists. The resources focus on introducing best practices in software engineering to students from the very start to make their software more useable, maintainable, and reproducible.  相似文献   

9.
In order to provide quality assurance in the field of clinical chemistry, required by European Standards, the Romanian national metrological infrastructure has to be improved. The main objectives of this important activity are metrological assurance of concentration measurements, the assessment of the uncertainty, and the traceability of measurements. Within this framework, reference materials play an important role. The experience of INM in the preparation, certification and use of reference materials and in metrological assurance of clinical laboratory measurements (especially when absorption photometric devices are used) is described. The combined uncertainty associated with chemical preparation of these reference materials is estimated. Received: 25 April 1997 / Revised: 8 July 1997 / Accepted: 12 July 1997  相似文献   

10.
The experimental design of a material certification programme is described. The matrix reference materials (RMs) comprised chlortetracycline (CTC)-containing and CTC-free lyophilised porcine liver, kidney and muscle produced under the European Commission’s Standards Measurements and Testing (SMT) programme. The aim of the certification programme was to determine accurately and precisely the concentration of CTC and 4-epi-chlortetracycline (epi-CTC) contained in the RMs. A multi-laboratory approach was used to certify analyte concentrations. Participants (n = 19) were instructed to strictly adhere to previously established guidelines. Following the examination of analytical performance criteria, statistical manipulation of results submitted by 13 laboratories, (6 withdrew) allowed an estimate to be made of the true value of the analyte content. The Nalimov test was used for detection of outlying results. The Cochran and Bartlett tests were employed for testing the homogeneity of variances. The normality of results distribution was tested according to the Kolmogorov-Smirnov-Lilliefors test. One-way analysis of variance (ANOVA) was employed to calculate the within and between-laboratory standard deviations, the overall mean and confidence interval for the CTC and epi-CTC content of each of the RMs. Certified values were within or very close to the target concentration ranges specified in the SMT contract. These studies have demonstrated the successful production and certification of CTC-containing and CTC-free porcine RMs.  相似文献   

11.
The experimental design of a material certification programme is described. The matrix reference materials (RMs) comprised chlortetracycline (CTC)-containing and CTC-free lyophilised porcine liver, kidney and muscle produced under the European Commission's Standards Measurements and Testing (SMT) programme. The aim of the certification programme was to determine accurately and precisely the concentration of CTC and 4-epi-chlortetracycline (epi-CTC) contained in the RMs. A multi-laboratory approach was used to certify analyte concentrations. Participants (n = 19) were instructed to strictly adhere to previously established guidelines. Following the examination of analytical performance criteria, statistical manipulation of results submitted by 13 laboratories, (6 withdrew) allowed an estimate to be made of the true value of the analyte content. The Nalimov test was used for detection of outlying results. The Cochran and Bartlett tests were employed for testing the homogeneity of variances. The normality of results distribution was tested according to the Kolmogorov-Smirnov-Lilliefors test. One-way analysis of variance (ANOVA) was employed to calculate the within and between-laboratory standard deviations, the overall mean and confidence interval for the CTC and epi-CTC content of each of the RMs. Certified values were within or very close to the target concentration ranges specified in the SMT contract. These studies have demonstrated the successful production and certification of CTC-containing and CTC-free porcine RMs.  相似文献   

12.
The peer evaluation of single accreditation bodies in order to sign an Arrangement for Recognition of the international accreditation organizations International Accreditation Forum, Inc. (IAF) and International Laboratory Accreditation Cooperation (ILAC), whether performed by Regional Accreditation Groups or directly by IAF and/or ILAC, is standard practice. The fundamental requirements for such evaluations are well specified in documents. However, the careful evaluation of all their Arrangement members poses an enormous logistic task for IAF and ILAC, and the signatories can be evaluated more thoroughly within their Regional Groups. Hence, IAF and ILAC typically evaluate only the Regional Accreditation Groups and accept all signatories of a Regional Accreditation Group once successfully evaluated by their respective Regional Group. However, the requirements for the evaluation of a Regional Group are extensive, and the evaluation procedure is highly complicated and must be conducted very carefully in order to assure that the results of accreditation can be trusted. This article describes the evaluation procedure used by IAF and/or ILAC for Regional Groups wishing to sign the IAF/ILAC Arrangement. We wish to inform and to aid these Regional Groups setting out for evaluation, and also to build confidence in the IAF/ILAC Arrangements.  相似文献   

13.
14.
Summary

The requirements, preparation, purification, characterisation, determination and certification of purity, utilisation and handling of reference materials for the analysis of organic pollutants found in the environment and workplace are reviewed in relation to specific groups of organic compounds.  相似文献   

15.
16.
This work describes the human resources organization of the General Coordination for Accreditation (Cgcre) in Brazil, in which lead and technical assessors, both internal and external to the National Institute of Metrology, Quality and Technology (Inmetro), assess the competence of calibration and testing laboratories to the ISO/IEC 17025:2005 standard. The “Lead Assessor Project” is presented, which consists of an increase in the responsibilities of lead assessors, in such a way that the Division of Laboratories Accreditation (Dicla/Cgcre) can cope with the increasing demand for ISO/IEC 17025:2005 accreditation of Brazilian calibration and testing laboratories.  相似文献   

17.
阐述了标准物质的应用和管理在科研设备质量控制体系中的重要性,指出了现阶段科研设备用标准物质存在的问题,并提出了对策。  相似文献   

18.
This paper describes a demonstrator case study of how a distributed metrology institute can bring value to the measurement infrastructure. The example is taken from the food measurement area, where the Metrology Institute of the Republic of Slovenia (MIRS) has set up a collaboration with the Slovenian National Food Reference Laboratory (NFRL) to act as the holder of the reference standard for the measurement of the content of protein in wheat. The responsibilities of the different parties are described; examples of the joint activities are given. The benefits of the co-operation are described in detail.  相似文献   

19.
Peer evaluation is used by the international accreditation organisations IAF and ILAC as a tool to harmonise the results of accreditation of conformity assessment bodies and as a control mechanism to ensure constantly competent services according to harmonized standards. Upon positive evaluation outcome, the accreditation body may join an Arrangement (MLA/MRA) between accreditation bodies, confirming systematic reliability and competence to the market. The objective of these Arrangements is that they will cover all accreditation bodies in all countries in the world, thus eliminating the need for suppliers of products or services to be certified in each country where they sell their products or services. This article is to aid single accreditation bodies wishing to sign these Arrangements in the future, and, furthermore, to communicate the procedure and the relevance of evaluation to the public in order to build up confidence in such Arrangements.  相似文献   

20.
A study of the reactivity pattern associated with zwitterionic allenolates "on water" is reported. This study establishes the chemical basis for two organocatalyzed allenolate-driven reaction networks operating "on water". The first one is a chemodifferentiating three building block (ABB') three-component reaction (ABB' 3CR) manifold comprising terminal alkynoates and aldehydes. The manifold produces propargylic enol ethers 3 with higher average efficiency than their homologues in organic solvents. The second one is a novel organocatalytic system elicited by the reaction of alkynoates and nitrones in the presence of tertiary amines or phosphines. While terminal alkynoates afford 2,3,5-trisubstituted 2,3-dihydroisoxazoles 5 and propargylic N-hydroxylamines 6, internal alkynoates selectively afford the 2,3,4,5-tetrasusbstituted 2,3-dihydroisoxazaole 10. Importantly, in both cases, the 2,3-dihydroisoxazole ring is obtained as a sole regioisomer.  相似文献   

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