IAEA Reference Materials
Reference
Sheets
IAEA-359
TRACE AND MINOR ELEMENTS IN CABBAGE
Intended
Use
This
sample is intended to be used as a reference material for the measurement
of trace and minor elements in vegetable matrices. 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
IAEA
359 Cabbage (Brassica oleracea var. Sabauda) was grown from seed in
the vicinity of the Agency’s laboratory in Seibersdorf, Austria. Since this
material was originally intended for use as an agrochemical reference material,
the seeds were treated with Lindane and Aziprotryne and during the growth
of the crop, it was treated with a further eight agrochemical compounds (Metazachlor,
Propachlor, Desmetryne, Endosulfan, Bromophos, (Lindane), Fluazifop-butyl,
Bitertanol and Trifluralin) [2]. Approximately 6000 Kg of the cabbage was
harvested by hand and then cut using an agricultural cutting machine. The
stems were removed by hand and 2200 Kg of the material was available for further
processing.
The raw material
was oven dried at 40 °C for several days and then stored in black polythene
bags (about 285 Kg). The dried cabbage was ground in an impact pulveriser
mill to pass through a 300 µm sieve and extruded into polythene bags.
This coarse fraction was then further processed in an air jet mill, resulting
in a particle size below 50 µm. Once air jet milled, the material was
placed in a large plastic drum and thoroughly mixed by continuous rotation
for a 24 hour period. The material was then bottled in acid washed brown glass
bottles which were sealed with a polythene cap. Each bottle contained approximately
30 g of the product. The sealed bottles were sterilised at 25 KGy using a
60Co source, to confer stability by inhibiting any microbial action
in the product.
Date of Release:
March 2000
|
Unit Price:
130 €
|
Unit Size:
30 g
|
| Producer:
Chemistry Unit Agency's Laboratories, Seibersdorf A-2444 Seibersdorf, Austria |
Supplier:
Analytical Quality Control Services Agency's Laboratories, Seibersdorf A-2444 Seibersdorf, Austria |
|
Reference Sheet:  IAEA-359(.pdf) |
||
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
|
| * | 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 four international intercomparison
exercises organized between 1992/1993. The details concerning the criteria
for qualification as a recommended or an information value can be found in
the report IAEA/AL/123 "Intercomparison runs for the determination of trace
and minor elements in cabbage material IAEA-359" [1]. This report is available
free of charge upon request.
Homogeneity
Since
the original purpose of IAEA 359 was as a reference material for agrochemical
residues, homogeneity testing at the time of production was focused on these
analytes and was conducted at a relatively high intake mass of 1 g [2]. In
parallel, a limited range of inorganic analytes was also tested using X-ray
Fluorescence (XRF), Instrumental Neutron Activation Analysis (INAA) and Atomic
Absorption Spectrometry (AAS), with sample intake masses in the range 0.1
to 1.0 g. The results indicated that the component of uncertainty due to the
heterogeneity of the material was less than or equal to five percent [2] for
trace and minor elements.
No systematic
attempt was made to evaluate the minimum representative sample size for IAEA-359.
However, subsequent analyses by INAA and XRF indicated that the material could
be considered to be homogeneous for Br, Co, Cs, Fe, Rb and Zn with intake
masses at or above 150 mg.
Dry
weight determination
All
recommended and information 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 500 mg dried to constant weight in a drying oven set to 100
°C. Subsequent weighings should differ by less than 5 mg.
Instructions
for use
The
recommended minimum sample size for analysis is 150 mg. Analysts are reminded
to take appropriate precautions in order to avoid contaminating the remaining
material in the bottle. It is recommended that the material be stored in a
dark place, below 25°C.
References:
| [1] | |
| [2] | Zeisler
R., Strachnov V., Perschke H. and Dekner R., The preparation of a cabbage
candidate reference material to be certified for residues of agrochemicals.
Fresenius J. Anal. Chem. 345 (1993) 202-206. |
Last updated 30 March 2004
