Fresenius J Anal Chem (1993) 345:254-255

Reference materials: global harmonization and the assurance of data quality H. Keune and M. Delve

Fresenius' Journal of

@ Springer-Verlag 1993

UNEP-HEM Office, c/o GSF (Research Centre for Environment and Health), Ingoldst/idter Landstrasse 1, W-8042 Neuherberg/Mtinchen, Federal Republic of Germany

Summary. The need for reference materials, and the prob- lems of locating information about them, are discussed. The first steps in the construction of a database on reference materials are described. The term reference materials was taken to mean any substance used to give a baseline or refer- ence value for a measurement. A broadly-phrased question- naire was sent out to 264 different organizations. So far 67 replies have been received representing a wide range of manufacturers, suppliers, and users of reference materials from 23 different countries. These replies have been com- piled to form a Survey of Institutions, Organizations and Laboratories Manufacturing, Supplying, or Using Reference Materials, which will soon be available in printing form. The first edition will serve as a basis for defining user needs more precisely, and developing a more detailed questionnaire. The information will be included in digitized form as a part of the HEM metadatabase information system HEMIS.

Introduction

Systematic and comprehensive monitoring is essential in order to provide a knowledge of the state of the environment and its departure from an assumed normal or historically recorded state. Sound scientific conclusions drawn from accurate and reliable data provide a foundation for the for- mulation of solid economic and legislative policy. The qual- ity of such data is ensured partly through the adoption of recognized methods of analysis, employed under controlled conditions [1]. To ensure the accuracy of data it is necessary to have some form of reference value which can be used to test the reliability and constancy of the measurement pro- cess. This usually means employing reference materials, which themselves need to be well-documented and tested if they are to provide a reliable guide for the verification of methodology, calibration of instrumentation and improve- ment of routine methods [2]. Despite the wealth of reference materials now available for a wide variety of applications, the search for a particular reference material, specific to the requirements of a programme, can be an arduous task. The fragmented information often only lists materials from inter- nationally known producers. Laboratories, limited by finan-

Correspondence to." H. Keune

cial constraints, require information concerning reference materials relevant to their feld of research, documentation and testing of these materials, availability and cost. Labora- tories may be unaware of similar research conducted over- seas and the materials that are used, and thus opportunity for cooperation and the transfer of resources is lost.

Harmonization of Environmental Measurement (HEM) is a programme implemented and funded by the United Nations Environment Programme (UNEP) and the Federal Republic of Germany and established under the auspices of the UNEP Global Environment Monitoring System (GEMS). The mission of HEM is to enhance the compatibil- ity and quality of information on the state of the environ- ment worldwide, so improving the provision of harmonized information which is required for the sound management of environment resources [3]. Knowledge of, and access to, proper reference materials is a prerequisite for improving the quality of laboratory and field data and thus for ensuring comparability of measurements. For this reason HEM is investigating ways of improving access to information about reference materials relevant to environmental measurement and monitoring programmes.

Database system

Assistance in locating the sources of supply of reference materials relevant to applications in environmental measure- ment and monitoring could be provided by an information system facilitating the collation of information from a variety of sources worldwide; i.e. a reference materials database. The primary objective of a database system is the provision of convenient and efficient retrieval and the storage of infor- mation. The definition of the structure for the storage of information, and the provision of mechanisms for the manipulation of the information, must be based in part upon user requirements and the material that is considered to be of value to current environment research programmes.

Database content

Various aspects of the use of reference materials must be considered when deciding what information needs to be included in the database. When selecting material it is necessary to know, for example, the period of validity of the reference materials, the storage conditions, and the specifi- cations for the validity of certified properties. The selection

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of reference material must also take into account the level of uncertainty allowed, and the chemical and physical suitabil- ity for the purpose for which the material is intended. The final selection depends on obtaining the best match with the composition of real samples. It is necessary to know what methods of laboratory analysis may be used with a material in the analysis of a specific sample. Such information on the materials available, and the properties which they exhibit, must be easily accessible, to allow proper selection of mate- rials and furthermore to guard against the possibility of misuse of a reference material.

Survey of organizations, institutes, and laboratories

As a first step in the construction of a reference materials database, the Harmonizat ion of Environmental Measure- ment Office has conducted a survey by questionnaire of institutions, organizations, and laboratories active in either the manufacture, supply or the use o f reference materials. This questionnaire was aimed at obtaining information about: 1. the type o f environment research/applications using refer-

ence materials and the types of materials employed; 2. the distribution of suppliers;

3. the availability of reference material advisory or consul- tancy services;

4. the proportion of manufacturers to users of selected groups of materials.

The questionnaire was sent to data centres, research institutions, university departments and commercial enter- prises concerned with the marketing of material. The ques- tionnaire was expressed in very general terms. No attempt was made to limit the definition of reference materials as, particularly in the field of environmental measurement, the term "reference material" can span a wide range o f sub- stances - from certified reference materials used for the cali- bration of instruments, to environmental specimens col- lected to provide a base-line reference for subsequent change at a specific site.

References

1. Izrael YA (1988) Environmental Monitoring and Assessment 11: 197-202

2. Wolf WR (ed) (1985) Biological reference materials: availability, uses and need for validation of nutrient measurement. Wiley, NewYork, Chichester

3. Keune H, Murray AB, Benking H (1991) Geojournal 23:249-255