IAEA Reference Materials
Reference
Sheets
IAEA-314
226Ra, Th AND U IN STREAM SEDIMENT
Intended
Use
This
sample is intended to be used as a reference material for the measurement
of 226Ra, Th and U in sediment samples. 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
stream sediment sample was collected from the Kalan area of the west Kalimantan
Borneo, Indonesia and was donated by the Indonesian Atomic Energy Commission
(IAEC).
The material
was air dried and then ground to pass through a 0.18 mm sieve before being
homogenized. The material was dispensed 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:
February 1991
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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-314(.pdf) |
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Reference
Date for decay correction: 30st January 1988 |
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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 1988. The details concerning the criteria for qualification
as a recommended value can be found in the report (IAEA/AL/038) "Report on
the Intercomparison Run IAEA 314: 226Ra, Th and U in Stream Sediment"
[1]. This report is available free of charge upon request.
Homogeneity
The
homogeneity of the bottled material was assessed by the determination of uranium
using laser fluorimetry in two 500 mg sub-samples taken from a number of bottles
chosen at random from the whole production run. The between and within bottle
variability was assessed (on the basis of the F test, at the 95% confidence
level) and indicated that the contribution due the heterogeneity of the material
was small and therefore the material could be considered to be homogeneous
for a sample size at or above 500 mg.
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 500 mg. 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
