IAEA Reference Materials
Reference
Sheets
IAEA-152
RADIONUCLIDES IN MILK POWDER
Intended
Use
This
sample is intended to be used as a reference material for the measurement
of radionuclides in milk powder. 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
The
milk powder was donated to the IAEA by a milk processing facility in the former
USSR. The material was produced from cow’s milk obtained from animals that
had grazed on land contaminated with radioactive fallout resulting from the
Chernobyl incident in 1986. A bulk sample of approximately 500 kg (in 25 kg
sacks) of milk powder prepared in a single batch was received by the Agency’s
Laboratories at Seibersdorf. After a preliminary homogeneity test, 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-152(.pdf) |
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Reference
Date for decay correction: 31st August 1987 |
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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 during 1987. The details concerning the criteria for qualification
as a recommended value can be found in the report (IAEA/AL/009) "Report on
the Intercomparison Run IAEA-152: Radionuclides in Milk Powder" [1]. This
report is available free of charge upon request.
Homogeneity
The
homogeneity of the bottled material was assessed by measuring the 134Cs
and 137Cs activities in twelve bottles, chosen at random, using
gamma spectrometry. On the basis of the results the contribution due the heterogeneity
of the material was less than 3% and therefore the milk powder could be considered
to be homogeneous for a sample size 250 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 sample size for analysis is 250 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
