Chemistry International
Vol. 21, No.5, September 1999
1999, Vol. 21
No. 5 (September)
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Chemistry International
Vol. 21, No. 5
September 1999
Report
on the IUPAC/ISO REMCO/BAM/EUROLAB-D Workshop on Proper Use of Environmental
Matrix Reference Materials
Berlin, Germany
22-23 April 1999
Dr. A. Fajgelj (Quality Assurance Supervisor, International
Atomic Energy Agency Laboratories, A-2444 Seibersdorf, Austria; E-mail:
[email protected]), Chairman
of the IUPAC Interdivisional Working Party on Harmonization of Quality
Assurance Schemes for Analytical Laboratories, has submitted the following
report:
IUPAC's Interdivisional Working Party on Harmonization
of Quality Assurance Schemes for Analytical Laboratories, ISO's Committee
on Reference Materials (ISO/REMCO), the German Federal Institute of
Materials Research and Testing (BAM), and EUROLAB-D of Germany, have
cooperated in organizing a workshop on "Proper Use of Environmental
Matrix Reference Materials". The workshop was sponsored by the
Institute for Reference Materials and Measurements (IRMM), European
Commission, Belgium; the Laboratory of the Government Chemists (LGC),
UK; and Promochem, Germany. It was supported by EURACHEM and hosted
by BAM in Berlin, Germany on 22 and 23 April 1999.
In principle, the aim of the workshop was to increase
awareness of how various types of reference materials (RMs) should be
utilized. For this purpose, experts from different RM-producing organizations
selected some of their existing RMs and focussed on the following topics:
a) how the materials were characterized; b) how the materials were certified
(absolute method, laboratory intercomparison, selected laboratories,
certification criteria etc.); c) information about the assigned property
values of traceability and uncertainty; and d) how the materials should
be utilized properly by analysts in view of points a, b and c. Some
lectures also included information about new strategies and plans in
RM production. Information about ISO REMCO and COMAR (a reference materials
database) was also given.
The following RM producers were represented at the
workshop: Canada Center for Mineral and Energy Technology (CANMET)-Canadian
Certified Reference Materials Project (CCRMP); Chinese National Research
Center for Certified Reference Materials (GWB); Faculty of Agronomy
and Institute of Chemical Technology, Czech Republic; Federal Institute
of Materials Research and Testing (BAM), Germany; Laboratory of the
Government Chemists (LGC), UK; Institute for Reference Materials and
Measurements (IRMM), European Commission; International Atomic Energy
Agency (IAEA); National Institute of Materials and
Chemical Research (NIMC), Japan; National Institute of Standards
and Technology (NIST), United States; National Office of Measures (OMH),
Hungary; and National Metrological Institute (NMI), Netherlands. In
addition, some posters were presented and an exhibition of RMs was organized
during the workshop.
From the general discussion, the following points can
be summarized:
- Matrix reference materials are a specific type of reference
materials. Within matrix reference materials, sub-groups also exist,
i.e., gaseous RMs, environmental and biological matrix RMs, alloys,
coal RMs, etc. To a large extent, differences in types of RMs are
reflected in possible methods of characterization and certification
of RMs and, consequently, in utilization of RMs in the analytical
process.
- A large majority of matrix RMs is characterized through interlaboratory
comparisons. Such materials do not always fulfill the criteria for
the established traceability of the assigned property values. Most
often, the uncertainty associated with the assigned property values
is not quantified as required by the ISO Guide on Expression of
Uncertainty in Measurement (GUM), Geneva, 1993.
- There is an urgent need for an up-to-date guidance on certification
principles that would cover the above points (traceability and uncertainty).
The new version of ISO Guide 35, Certification of Reference Materials:
General and Statistical Principles, which is currently under revision
by ISO/REMCO, will close this gap. Its first draft is expected to
be available next year.
- Matrix RMs are frequently prepared for different purposes, i.e.,
calibration (gaseous RMs, stable isotope ratio RMs, alloys, etc.).
The majority of matrix RMs available currently and in the future is
and will be suitable for method validation, quality assurance, and
quality control purposes, but not for calibration. Thus, the intended
use of matrix RMs needs to be specified clearly by the producer.
- The instructions on proper use of reference materials given in ISO
Guide 33 are of a general nature, because they are intended to cover
all types of certified reference materials. Because ISO Guide 33,
Uses of Certified Reference Materials, is also not in accordance
with the GUM, it urgently needs to be revised. Additional guidance
has to be prepared by the producers for each RM separately to reflect
the intended use of the RM.
- It is the responsibility of an RM user to obtain the necessary
information on the quality of an RM before selecting and using it
for a specific purpose in the laboratory.
According to responses to a questionnaire distributed during the workshop,
urgent and future needs for the following types of RMs were identified:
Matrix |
Analyte |
|
Surface, ground, and wastewater |
PCBs, PAHs, and pesticides |
Aqueous solutions |
Diverse pollutants from the atmosphere
|
Marine material, e.g., fish tissue |
Trace elements |
Soils and sediments |
Trace metals, PCBs, and PAHs |
Vegetables |
Pesticides (different European limits) |
Gas |
Organics |
The workshop was attended by more than 100 participants
from 34 countries. Full text of the lectures given by 17 presenters
can be found in a special series proceedings book entitled The
Use of Matrix Reference Materials in Environmental Analytical Processes
(ISBN 0 85404 739 5) published by The Royal Society of Chemistry
(see previous announcement in Chemistry International, 1999,
Vol. 21, No. 3, p. 87).
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