EN ISO 8294:1999

SLOVENSKI STANDARD
01-julij-2000
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Animal and vegatable fats and oils - Determination of copper, iron and nickel contents -
Graphite furnace atomic absorption method (ISO 8294:1994)
Tierische und pflanzliche Fette und Öle - Bestimmung des Gehaltes an Kupfer, Eisen
und Nickel - Graphitofen - Atomabsorptionsverfahren (ISO 8294:1994)
Corps gras d'origines animale et végétale - Détermination de la teneur en cuivre, fer et
nickel - Méthode par spectrométrie d'absorption atomique avec four en graphite (ISO
8294:1994)
Ta slovenski standard je istoveten z: EN ISO 8294:1999
ICS:
67.200.10 5DVWOLQVNHLQåLYDOVNH Animal and vegetable fats
PDãþREHLQROMD and oils
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL
IS0
STANDARD 8294
First edition
1994-I I-01
Animal and vegetable fats and oils -
Determination of copper, iron and nickel
contents - Graphite furnace atomic
absorption method
Corps gras d ’origines animale et &g&ale - 06 termination de la teneur
en cuivre, fer et nickel - M&hode par spectrom6trie d ’absorption
atomique avec four en graphite
Reference number
IS0 8294: 1994(E)
IS0 8294: 1994(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(I EC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 8294 was prepared by Technical Committee
ISOfTC 34, Agricultural food products, Subcommittee SC 1 I, Animal and
vegetable fats and oils.
Annex A of this International Standard is for information only.
0 IS0 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
INTERNATIONAL STANDARD 0 IS0 IS0 8294: 1994(E)
- Determination
Animal and vegetable fats and oils
- Graphite furnace
of copper, iron and nickel contents
atomic absorption method
4 Reagents
1 Scope
Use only reagents of recognized analytical grade and
This International Standard specifies a method for the
water in accordance with grade 2 of IS0 3696.
determination of trace amounts of copper, iron and
nickel in animal and vegetable fats and oils, referred
to hereinafter as fats.
4.1 Aluminium oxide, analytical grade.
NOTE 1 A suitable aluminium oxide (Quality No. 1077) is
2 Normative references
available from Merck, D-l 600 Darmstadt, Germany?
The following standards contain provisions which,
through reference in this text, constitute provisions
4.2 Dilution oil, for example a refined edible oil,
of this International Standard. At the time of publi-
liquid at ambient temperature.
cation, the editions indicated were valid. All standards
are subject to revision, and parties to agreements Store the oi! in a metal-free polyethylene or
based on this International Standard are encouraged
polyethylene bottle (5.1). Metal contents of the oil
to investigate the possibility of applying the most re-
shall be not greater than:
cent editions of the standards indicated below.
Members of IEC and IS0 maintain registers of cur- Cu, 3 pg/kg;
rently valid International Standards.
Fe, 5 pg/kg; and
IS0 661: 1989, Animal and vegetable fats and oils -
Preparation of test sample. NL 5 pglkg.
NOTE 2 A sample of near-metal-free oil may be obtained
IS0 3696: 1987, Water for analytical laboratory use -
by the following procedure.
Specification and test methods.
Dissolve the oil in light petroleum (boiling range 40°C to
60 “C) in a ratio of 1 kg of oil to 3 litres of light petroleum.
Prepare an aluminium oxide column (diameter/height ratio
3 Principle
= l/IO) using twice the mass of aluminium oxide (activated
by heating at 150 “C for 14 h) as the mass of the oil to be
Vaporization of a test portion of the fat in a graphite
purified. Add the solution to the column and elute a volume
atomic absorption
furnace connected to an
of light petroleum 5/3 times as much as the volume the
spectrometer, previously calibrated using standard
sample was dissolved in. Evaporate the light petroleum
solutions of organ0 compounds of the metals under
from the eluate on a heated water-bath using a gentle
test. Calculation of the metal contents from the stream of nitrogen (2 l/min to 5 I/min). Remove the final
traces of light petroleum under vacuum.
absorbances at selected wavelengths.
1) This information is given for the convenience of users of this International Standard and does not constitute an endorsement
by IS0 of this product.
0 IS0
IS0 8294: 1994(E)
acid solution [c(HNOJ = 1 mol/l], rinsing with water and
4.3 Standard stock solutions
then drying in an oven at about 80 “C.
By appropriate dilution of organometallic standards
with the dilution oil (4.21, prepare standard stock sol- 5.2 Micropipettes, of 20 ~1 and 100 ~1 capacity.
utions containing respectively:
5.3 Pipette tips
Cur 2 w/kg;
5.4 Electric oven, capable of being maintained at
Fe, 10 mg/kg; and
150 “C + 2 “C.
-
Ni, 10 mg/kg.
5.5 Atomic absorption spectrometer, equipped
with either “peak height” mode and printer, or “con-
NOTE 3 Suitable standards are available from Continental
tinuous” mode and pen recorder (full-scale response
Oil Company, Ponca City, Oklahoma, USA (Conostan,
5 000 mg/kg), or Merck, D-l 600 Darmstadt, Germany in 0,2 s), together with appropriate hollow cathode
(1 000 mg/kg).l)
tube or electrodeless discharge lamp and deuterium
background corrector.
4.4 Standard working solutions
5.6 Graphite furnace atomizer, placed in the
Prepare working solutions as required on the day of
atomic absorption spectrometer (5.5), equipped with
use with the following concentrations, by diluting the
a control unit for temperature programming and a
stock solutions (4.3) with the dilution oil (4.2):
graphite tube.
Cu: 0,05 mg/kg; 0,l mg/kg; 0,2 mg/kg
e, uncoated for atomization.
Fe: 0,25 mg/kg; 0,5 mg/kg; I,0 mg/kg
amplin
Ni: 0,25 mg/kg; 0,5 mg/kg; I,0 mg/kg
It is important that the laboratory receive a sample
which is truly representative and has not been dam-
containing
4.5 Niobium solution [N b( NO&,
aged or changed during transport and storage.
1 000 mg of niobium per litre; “AAS standard solution
in aqueous matrix ”.
Sampling is not part of the method specified in this
International Standard. A recommended sampling
A suitable solution is available from Alfa Division,
NOTE 4
method is given in IS0 5555.
152 Andover Street, Danvers, MA 01923, USA (code
88083). ‘)
7 Preparation of test sample
n-Heptane, analytical grade.
4.6
Prepare the test sample in accordance with IS0 661.
Do not filter the test sample.
4.7 Argon, minimum purity 99,99 %.
If argon is not available, nitrogen may be used
NOTE 5
8 Procedure
as the p
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