IAEA Reference Materials
Reference
Sheets
IAEA-153
TRACE ELEMENTS IN MILK POWDER
Intended
Use
This
sample is intended to be used as a reference material for the measurement
of trace elements in milk powder. The material 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 50 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:
May 1989
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Unit Price:
50 €
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Unit Size:
50 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-153(.pdf) |
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| * |
Number of accepted laboratory results which were used to calculate the
recommended or information 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/010) "Report on
the Intercomparison Run IAEA-153: Trace Elements in Milk Powder" [1]. This
report is available free of charge upon request.
Homogeneity
The
homogeneity was evaluated by determining the content of two marker elements
(Ca and Zn) by atomic absorption spectrometry (AAS) and inductively coupled
plasma atomic emission spectrometry (ICP-OES) in single samples (300 mg) taken
from ten bottles, selected at random. 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 300 mg.
Dry
weight determination
All
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 300 mg. Analysts are reminded
to take appropriate precautions in order to avoid contaminating the remaining
material in the bottle. No special precautions are required for the storage
of this material.
References:
| [1] |
Last updated 30 March 2004
