IAEA Reference Materials
Reference
Sheets
IAEA-321
RADIONUCLIDES IN MILK POWDER
Intended
Use
This
sample is intended to be used as a reference material for the measurement
of radionuclides in milk products. It can also be used as a quality control
material for the assessment of a laboratory's analytical work, for the validation
of analytical methods and for quality assurance within a laboratory.
Origin
and preparation of the material
A
single batch bulk sample of approximately 500 kg of milk powder with elevated
levels of radionuclides was collected from an European dairy products processing
plant and dispatched to the Agency’s Laboratories at Seibersdorf in autumn
1987. The material was bottled into plastic bottles in 250 g units without
any further processing. Subsequently, the samples were irradiated to a dose
of 2.5 x 104 Gy using a 60Co source to ensure long-term
stability of the material by inhibiting microbial action.
Date of Release:
November 1988
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Unit Price:
50 €
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Unit Size:
250 g
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| Producer:
Chemistry Unit Agency's Laboratories, Seibersdorf A-2444 Seibersdorf, Austria |
Supplier:
Analytical Quality Control Services Agency's Laboratories, Seibersdorf A-2444 Seibersdorf, Austria |
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Reference Sheet:  IAEA-321(.pdf) |
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Reference
Date for decay correction: 1st January 1989 |
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Number of accepted laboratory results which were used to calculate the
recommended values and their respective confidence intervals about the
mean value. |
| (R/I) | Classification
assigned to the property value for Analyte (Recommended/Information) |
The
values listed above were established on the basis of statistically valid results
submitted by laboratories which had participated in an international intercomparison
exercise organized between 1988-89. The details concerning the criteria for
qualification as a recommended value can be found in the report (IAEA/AL/026)
"Report on the Intercomparison Run IAEA-321: Radionuclides in Milk Powder"
[1]. This report is available free of charge upon request.
Homogeneity
The
homogeneity of the bottled material was assessed for intake mass of 100 g
by measuring the 40K, 134Cs and 137Cs activities
in ten bottles, chosen at random, using gamma spectrometry. Taking into account
the statistical counting uncertainties, this material can be considered sufficiently
homogeneous for an intake mass greater than or equal to 100 g.
Dry
weight determination
All
recommended values are expressed on a dry weight basis. Therefore the dry
weight must be determined at the time of analysis, using separate sub-samples
of at least 500 mg dried to constant weight in a drying oven set to 105 °C.
Subsequent weighings should differ by less than 5 mg.
Instructions
for use
The
recommended minimum sample size for analysis is 100 g. Analysts are reminded
to take appropriate precautions in order to avoid contamination of the material
during handling. No special precautions are required for the storage of this
material.
References:
| [1] |
Last updated 30 March 2004
