Calculo de incertidumbre en laboratorio

TR 537
Approved 2004-02

HANDBOOK FOR CALCULATION OF MEASUREMENT UNCERTAINTY IN ENVIRONMENTAL LABORATORIES EDITION 2

Bertil Magnusson Teemu Näykki Håvard Hovind Mikael Krysell

Published by Nordtest Tekniikantie 12 FIN–02150 Espoo Finland

Phone: + 358 9 455 4600 E-mail: nordtest@nordtest.org

Fax: + 358 9 455 4272 Internet: www.nordtest.org

NT TECHN REPORT 537 Edition 2Approved 2004-02

Authors: Bertil Magnusson1 Teemu Näykki2 Håvard Hovind3 Mikael Krysell4

NORDTEST project number: 1589-02

1)

Institution: SP, Sweden, 2) SYKE, Finland, 3) NIVA, Norway, 4) Eurofins A/S, Denmark

Title (English): Title (Original): Abstract: This handbook is written for environmental testing laboratories in the Nordic countries, in order to give support to theimplementation of the concept of measurement uncertainty for their routine measurements. The aim is to provide a practical, understandable and common way of measurement uncertainty calculations, mainly based on already existing quality control and validation data, according to the European accreditation guideline /12/, the Eurolab Technical Report No. 1 /3/ and the ISO/DTS 21748 Guide /8/. Nordtest hassupported this project economically in order to promote and enhance harmonisation between laboratories on the Nordic market. Practical examples, taken directly from the everyday world of environmental laboratories, are presented and explained. However, the approach is very general and should be applicable to most testing laboratories in the chemical field. The handbook covers all steps in theanalytical chain from the arrival of the sample in the laboratory until the data has been reported. It is important to notice that vital parts of the total measurement uncertainty are not included, e.g. sampling, sample transportation and possible gross errors during data storage/retrieval. The recommendations in this document are primarily for guidance. It is recognised that while the recommendationspresented do form a valid approach to the evaluation of measurement uncertainty for many purposes, other suitable approaches may also be adopted – see references in Section 9. Especially the EURACHEM/CITAC-Guide /2/ is useful in cases where sufficient previous data is not available, and therefore the mathematical analytical approach according to GUM /1/ with all different steps is to be used.Basic knowledge in the use of quality control and statistics is required. In order to make it possible for the reader to follow the calculations, some raw data is given in appendices. Handbook for Calculation of Measurement Uncertainty in Environmental Laboratories

Technical Group: Expert Group Quality and Metrology ISSN: 0283-7234 Class (UDC): 620.1 Distributed by: NORDTEST Tekniikantie 12FIN-02150 ESPOO Finland Language: English Key words: Pages: 41

handbook, laboratories, environmental, testing, measurements, uncertainty, chemical

Publication code: Report Internet address: http://www.nordtest.org/register/techn/tlibrary/tec537.pdf

Handbook
for

Calculation of Measurement Uncertainty
in

Environmental Laboratories

Version 1.3 October 2003
Nordtest project1589-02
Project participants Bertil Magnusson, SP, Sweden Teemu Näykki, SYKE, Finland Håvard Hovind, NIVA, Norway Mikael Krysell, Eurofins A/S, Denmark Drawings by Petter Wang, NIVA, Norway Valuable comments on the contents have been provided by: Rolf Flykt, Sweden Irma Mäkinen, Finland Ulla O. Lund, Denmark Steve Ellison, UK

Contents:
1 2 DEFINITIONS AND ABBREVIATIONS...................................................... 1 INTRODUCTION............................................................................................ 3
2.1 2.2 2.3 SCOPE AND FIELD OF APPLICATION .......................................................................... 3 COMMENT TO CUSTOMERS ....................................................................................... 3 ABOUT MEASUREMENT...