ISO 14181:2000
(Main)Animal feeding stuffs — Determination of residues of organochlorine pesticides — Gas chromatographic method
Animal feeding stuffs — Determination of residues of organochlorine pesticides — Gas chromatographic method
This International Standard specifies a gas chromatographic method for the determination of residues of organochlorine pesticides in animal feeding stuffs. The method is applicable to animal feeding stuffs containing residues of one or more of the following organochlorine pesticides and some of their isomers and degradation products: aldrin, op'-DDE, pp'-DDE, op'-DDT, pp'-DDT, dieldrin, endosulfan, endrin, HCB, _-HCH (_-BHC), _-HCH (_-BHC), _-HCH (_-BHC), _-HCH (_-BHC), heptachlor, heptachlor epoxide, op'-TDE (op'-DDD), pp'-TDE (pp'-DDD) and methoxychlor. The lower determination limit for these organochlorine pesticides is 0,005 _g/g. However, the lower determination limit is 0,01 _g/g for op'-DDT and pp'-DDT, and 0,05 _g/g for methoxychlor.
Aliments des animaux — Détermination des résidus de pesticides organochlorés — Méthode par chromatographie en phase gazeuse
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 14181
First edition
2000-09-15
Animal feeding stuffs — Determination
of residues of organochlorine pesticides —
Gas chromatographic method
Aliments des animaux — Détermination des résidus de pesticides
organochlorés — Méthode par chromatographie en phase gazeuse
Reference number
©
ISO 2000
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ii © ISO 2000 – All rights reserved
Contents Page
Foreword.iv
1 Scope .1
2 Normative references .1
3 Principle.1
4 Reagents and materials .1
5 Apparatus .3
5.1 Grinder .5
6 Sampling.5
7 Preparation of test sample.5
8 Procedure .5
8.1 General.5
8.2 Test portion .5
8.3 Extraction .5
8.4 Column clean-up.6
8.5 Gas chromatography.6
9 Expression of results .7
9.1 Calculation.7
9.2 Recovery.8
10 Confirmation of identity .8
11 Precision.8
11.1 Interlaboratory test .8
11.2 Repeatability.8
11.3 Reproducibility.8
12 Test report .9
Annex A (informative) Examples of GC operating conditions for organochlorine pesticides.10
Annex B (informative) Results of interlaboratory test.11
Bibliography.20
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO 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. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
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.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 14181 was prepared by Technical Committee ISO/TC 34, Food products,
Subcommittee SC 10, Animal feeding stuffs.
Annexes A and B of this International Standard are for information only.
iv © ISO 2000 – All rights reserved
INTERNATIONAL STANDARD ISO 14181:2000(E)
Animal feeding stuffs — Determination of residues of
organochlorine pesticides — Gas chromatographic method
1 Scope
This International Standard specifies a gas chromatographic method for the determination of residues of
organochlorine pesticides in animal feeding stuffs.
The method is applicable to animal feeding stuffs containing residues of one or more of the following
organochlorine pesticides and some of their isomers and degradation products: aldrin, op'-DDE, pp'-DDE, op'-DDT,
pp'-DDT, dieldrin, endosulfan, endrin, HCB, �-HCH (�-BHC), �-HCH (�-BHC), �-HCH (�-BHC), �-HCH
(�-BHC), heptachlor, heptachlor epoxide, op'-TDE (op'-DDD), pp'-TDE (pp'-DDD) and methoxychlor.
The lower determination limit for these organochlorine pesticides is 0,005�g/g. However, the lower determination
limit is 0,01 �g/g for op'-DDT and pp'-DDT, and 0,05�g/g for methoxychlor.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent edition of the normative document indicated below. For
undated references, the latest edition of the normative documents referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods.
ISO 6498, Animal feeding stuffs — Preparation of test samples.
3Principle
A test portion is extracted with acetone. The filtered extract is diluted with water and saturated sodium chloride
solution. The pesticides are partitioned into dichloromethane. The concentrated extract is purified on a
chromatographic column of 10 % water-deactivated silica gel. The pesticide residues are determined by gas
chromatography using an electron capture detector or a mass selective detector.
4 Reagents and materials
Use only reagents of recognized analytical grade and with a purity suitable for pesticide residue analysis.
Check the purity of the reagents by performing a blank test under the same conditions as used in the method. The
chromatogram should not show any interfering impurity.
WARNING — Some of the organic solvents are suspected carcinogens. Use with care.
4.1 Water, complying with at least grade 3 in accordance with ISO 3696.
4.2 Hexane.
4.3 Acetone.
4.4 Dichloromethane.
4.5 Silica gel 60, with a mass fraction of water of 10 %.
Activate silica gel 60, particle size 63�mto 200�m, at 130 °C overnight, then cool in a desiccator. After cooling to
room temperature, pour the silica gel into an airtight glass container and add sufficient distilled water to bring the
final mass fraction of water to 10 %. Shake the container mechanically or by hand vigorously for 30 s and allow to
stand for 30 min with occasional shaking. After 30 min the silica gel is ready for use. It should not be stored for
morethan6h.
4.6 Eluting solvent: dichloromethane in hexane, 20 % (by volume).
Mix 1 volume of dichloromethane with 4 volumes of hexane.
4.7 Inert gas, for example nitrogen.
4.8 Sodium sulfate, anhydrous.
4.9 Sodium chloride, saturated solution.
4.10 Pesticide reference standards, as follows:
� aldrin [(1R,4S,4aS,5S,8R,8aR)-1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-1,4:5,8-dimethano-
naphthalene];
� op'-DDE [o,p'-(1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene)];
� pp'-DDE [p,p'-(1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene)];
� op'-DDT [o,p'-(1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane)];
� pp'-DDT [p,p'-(1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane)];
� dieldrin [(1R,4S,4aS,5R,6R,7S,8S,8aR)-1,2,3,4,10,10-hexachloro-1,4,4a,5,6,7,8,8a-octahydro-6,7epoxy-
1,4:5,8-dimethanonaphthalene];
� endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide);
� endrin [(1R,4S,4aS,5S,6S,7R,8R,8aR)-1,2,3,4,10,10-hexachloro-1,4,4a,5,6,7,8,8a-octahydro-6,7-epoxy-
1,4:5,8-dimethanonaphthalene];
� HCB (hexachlorobenzene);
��-HCH (�-BHC) (�-1,2,3,4,5,6-hexachlorocyclohexane);
��-HCH (�-BHC) (�-1,2,3,4,5,6-hexachlorocyclohexane);
��-HCH (�-BHC; lindane) (�-1,2,3,4,5,6-hexachlorocyclohexane);
��-HCH (�-BHC) (�-1,2,3,4,5,6-hexachlorocyclohexane);
� heptachlor (1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene);
� heptachlor epoxide (heptachloroepoxy-tetrahydromethanoindene);
2 © ISO 2000 – All rights reserved
� op'-TDE (op-DDD) [o,p'-1,1-dichloro-2,2-bis(4-chlorophenyl) ethane];
� pp'-TDE (pp'-DDD) [p,p'-1,1-dichloro-2,2-bis(4-chlorophenyl) ethane];
� methoxychlor [1,1,1-trichloro-2,2-bis(4-methoxyphenyl) ethane].
4.11 Internal standard: mirex (1,3,5-tribromobenzene) or pentachloronitrobenzene.
4.12 Pesticide standard and internal standard solutions.
4.12.1 Stock solutions, of concentration 1 000�g/ml.
Prepare a stock solution of each pesticide reference standard (4.10) and of the internal standard (4.11) as follows.
Weigh, to the nearest 0,1 mg, a mass of a pesticide reference standard (4.10) or the internal standard (4.11) which
will result in a solution with a content of reference standard or internal standard of 1 000�g/ml. While weighing,
observe the cleanness of the standard matrial. Transfer the weighed mass into a volumetric flask, dissolve in
hexane or in an other solvent such as toluene or iso octane. However, dissolve�-HCH in acetone. Dilute to volume
with the same solvent and mix well.
These solutions are stable for 6 months when stored at 4�Cinthedark.
4.12.2 Intermediate solutions, of concentration 10�g/ml.
Pipette 1 ml of each stock solution (4.12.1) into individual 100 ml volumetric flasks. Dilute to volume with hexane.
The solutions are stable for at least 3 months when stored at 4 °C in the dark.
NOTE The stability of properly stored pesticide standards is very widely known. Investigations have shown that all neat
pesticide standards tested are stable for 15 years when stored at –18 °C and that stock solutions of pesticide standards in
toluene of 1mg/ml are stable for at least 3 years when stored at –18 °C.
The following recommended practice may be used for longer storage. Transfer portions of the prepared standard
solutions to amber vials with PTFE-lined screwcaps. Weigh the vials and store at –20 °C. When needed, remove a
vial from the freezer, bring to room temperature and weigh. If the accumulated loss in mass due to evaporation is
10 % or more of the prefrozen net mass, discard the vial. Weigh and refreeze stock standards and intermediate
solutions that are in use for more than 3 months (usually in 25 ml vials). Otherwise the prepared standard solutions
(usually in 2 ml vials) may be stored at 4 °C and shall be discarde
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