IAEA Reference Materials
Reference
Sheets
REFERENCE MATERIAL
IAEA-433
TRACE ELEMENTS AND METHYLMERCURY
IN MARINE SEDIMENT
Intended
Use
This
material is intended to be used as a reference material for the measurement
of trace elements and methylmercury (MeHg) in sediment samples. It can also
be used as a quality control material for the assessment of analytical procedures,
in the elaboration and validation of analytical methods, and for educational
purposes.
Origin
and preparation of the material
A
large quantity of marine sediment was collected in 2002 off the Algerian coast
of the Mediterranean Sea for use as an intercomparison material. It was deep-frozen,
freeze-dried, then ground and sieved. The particle size fraction <250 µ
was homogenized and bottled in clean plastic bottles. After verifying the
homogeneity of the sample material (see below), the samples were rebottled
by packing aliquots of approximately 20 g into cleaned, brown borosilicate
glass bottles with Teflon lined screw caps and sealed in plastic bags.
Approximately 500 bottles were produced.
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Date of Release:
23
July 2004
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Unit Price:
90 Euro
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Unit Size:
10 g
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| Producer:
Marine Environment Laboratory (MEL) International Atomic Energy Agency 4 Quai Antoine 1er MC-98000 Monaco |
Supplier:
Analytical Quality Control Services Agency's Laboratories, Seibersdorf A-2444 Seibersdorf, Austria |
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Reference Sheet:
IAEA-433(.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.
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| (R/I) | Classification assigned to the property value for Analyte (Recommended/Information) |
The values listed above were established on the basis of results submitted
by laboratories that had participated in an international intercomparison
exercise organized in 2003. The details concerning the criteria for qualification
as recommended or information value can be found in the “Report on the
world-wide intercomparison exercise for the determination of trace elements
and methylmercury in marine sediment IAEA-433” [1]. This report is available
free of charge upon request.
Homogeneity
Extensive homogeneity tests were carried out on this material in order to
ensure its suitability as an intercomparison sample. A homogeneity pre-test
was conducted before bottling the sample material. The between-bottle homogeneity
was tested by the determination of the concentration of some typical elements
(Mn, Co, Cu, Zn, Hg) on sample intakes of 0.2 g taken from 10 bottles, which
were taken directly from the bulk material, specifically for the purpose of
this pre-test. The within-bottle homogeneity was assessed by 6 replicate determinations
on the re-homogenized content of one bottle. The uncertainty of the analytical
methods was assessed for each element by 5 replicate measurements on one digest
solution.
An F-test at a significance level of 0.05 was performed for the different
metals and did not reveal significant differences between the within- and
between-bottle variances, indicating that the heterogeneity observed was relatively
consistent, and independent of how the material was distributed. It was concluded
that the material was homogeneous for the elements tested at an analytical
portion of 200 mg and above; it is therefore suitable for use as an intercomparison
sample [1].homogeneity of the material for organochlorine compounds and petroleum
hydrocarbons was checked by determining the concentration of some compounds
(chlorinated pesticides and petroleum hydrocarbons) in 10 replicate analyses
taken randomly in the bulk of the powder. A one-way variance analysis indicated
that the material could be considered homogeneous.
Dry weight determination
The
average moisture content of the lyophilised sample after bottling, determined
by drying to a constant weight at 105°C, was found to be 1.9 %. Since
the moisture content can vary with the ambient humidity and temperature, it
is recommended that the water content of this material be determined in a
separate subsample (not used for analysis) by drying to a constant weight
(~24 hours) at 105°C just prior to analysis. Final results should always
be reported on a dry weight basis.
Instructions
for use
The
recommended minimum sample size for analysis is 200 mg. Analysts are reminded
to take ppropriate precautions in order to avoid contaminating the remaining
material in the bottle. The bottle should be thoroughly mixed by shaking before
use and tightly resealed immediately after use. The material should be stored
in the dark and kept below 25 ºC.
Legal disclaimer
The IAEA makes no warranties, expressed or implied, with respect to the data
contained in this reference sheet and shall not be liable for any damage that
may result from the use of such data.
References:
| [1] |
Wyse, E. J., S. Azemard and S. J. de Mora, 2004. Report on the world-wide
intercomparison exercise for the determination of trace elements and methylmercury in marine sediment IAEA-433. IAEA/AL/147, IAEA/MEL/75, IAEA, pp. 113. |
Last updated 01 June 2006
