ISO 17239:2004

INTERNATIONAL ISO
STANDARD 17239
First edition
2004-10-15
Fruits, vegetables and derived
products — Determination of arsenic
content — Method using hydride
generation atomic absorption
spectrometry
Fruits, légumes et produit dérivés — Détermination de la teneur en
arsenic — Méthode par spectrométrie d'absorption atomique à
génération de hydrure
Reference number
©
ISO 2004
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ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
1 Scope. 1
2 Principle . 1
3 Reagents . 1
4 Apparatus . 2
5 Sample. 3
6 Procedure . 3
7 Calculation. 5
8 Precision . 5
9 Test report . 6
Annex A (normative) Apparatus . 7
Annex B (informative) Results of the interlaboratory test. 9
Bibliography . 10

Foreword
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(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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established has the right to be represented on that committee. International organizations, governmental and
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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
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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 17239 was prepared by Technical Committee ISO/TC 34, Food products,
Subcommittee SC 3, Fruit and vegetable products.

iv © ISO 2004 – All rights reserved

INTERNATIONAL STANDARD ISO 17239:2004(E)

Fruits, vegetables and derived products — Determination of
arsenic content — Method using hydride generation atomic
absorption spectrometry
1 Scope
This International Standard specifies a hydride generation atomic absorption spectrometric method for the
determination of the arsenic content of fruits, vegetables and derived products.
NOTE The method of arsenic determination in fruit, vegetables and derived products is based on AOAC Official
Methods for Analysis (see Reference [1]).
2 Principle
Organic matter is decomposed by digestion with HNO in a closed system. Arsenic(V) is reduced to
arsenic(III) with potassium iodide, and hydrides of arsenic are generated by the action of sodium borohydride
prior to atomization in a flame-heated quartz cell. Measurement is by atomic absorption spectrometry.
3 Reagents
Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized
water or water of equivalent purity.
3.1 Nitric acid, concentrated, (ρ = 1,38 g/ml).
3.2 Hydrochloric acid, 8 mol/l solution.
Place 66 ml of concentrated hydrochloric acid (ρ = 1,19 g/ml) in a 100 ml one-mark volumetric flask and
make up to the mark with water. Mix.
3.3 Hydrochloric acid, diluted 1 + 1, by volume.
Mix one volume of concentrated hydrochloric acid (ρ = 1,19 g/ml) with one volume of water.
3.4 Magnesium chloride, 37,5 mg/ml solution.
Dissolve, in a 100 ml one-mark volumetric flask, 3,75 g of magnesium oxide by gradually adding
approximately 20 ml of hydrochloric acid solution (3.2) and make up to the mark with water. Mix.
3.5 Magnesium nitrate, 75 mg/ml solution.
Dissolve, in a 50 ml one-mark volumetric flask, 3,75 g of magnesium oxide with approximately 30 ml of water.
Slowly add approximately 10 ml of nitric acid (3.1) and mix. Make up to the mark with water.
3.6 Sodium borohydride, 4 % solution.
Dissolve, in a 100 ml one-mark volumetric flask, 4 g of NaBH in 4 % sodium hydroxide. Mix and make up to
the mark with 4 % sodium hydroxide.
3.7 Potassium iodide, 20 % solution.
Dissolve, in a 100 ml one-mark volumetric flask, 20 g of potassium iodide in water. Mix and make up to the
mark with water. Prepare just before use.
3.8 Arsenic, standard solution corresponding to 1,0 mg of arsenic per millilitre.
4 Apparatus
Rinse all glassware before using with a nitric acid solution (diluted 1 + 1), followed by a thorough rinse with
water.
Decontaminate the digestion vessels by digesting with reagents to be used in digestion. Rinse thoroughly with
water.
Usual laboratory apparatus and, in particular, the following.
4.1 Mechanical grinder, the inside and blades of which are coated with polytetrafluoroethylene (PTFE).
4.2 Atomic absorption spectrometer, provided with an air/acetylene burner (10 cm) and hydrogen-
nitrogen-entrained air flames, suitable for measurement at a wavelength of 193,7 nm and equipped with a
deuterium-arc background correction.
4.3 Decomposition vessel, 70 ml (see Figure A.1), consisting of a stainless steel body supporting a
polytetrafluoroethylene (PTFE) crucible having a screw-cap with a PTFE liner to provide a PTFE sealing
surface.
A PTFE spout is snapped on outside the rim to permit a quantitative transfer of the contents without contacting
the metal parts.
4.4 Oven, capable of maintaining a temperature of 150 °C.
4.5 Furnace, capable of maintaining a temperature of 450 °C.
4.6 Hydride generator, (see Figure A.2), constructed from the following:
4.6.1 Flat-bottom flask, borosilicate glass, 50 ml capacity.
4.6.2 Stoppers, two-hole (one through the centre), No 9 rubber stopper, with a gas-outlet tube of
polyethylene tubing, 100 mm long with a 3,2 mm id, fitted through the centre hole.
4.6.3 Reagent-cup assembly, consisting of the bottom 25 mm of a polyethylene test tube with a hole in the
bottom, through which the lower end of a gas-outlet tube is placed so that 3 mm of a tube protrudes below the
lower edge of the test tube.
1)
Connect the other end of the outlet tubing to the atomic absorption spectrometer (4.2) with 500 mm Tygon
tubing by cutting the auxiliary line approximately 75 mm from the mixing chamber and attaching the tubing.

1) Tygon is the trade name of a product. This information is only given for the convenience of users of this International
Standard and does not constitute an endorsement by ISO of this product.
2 © ISO 2004 – All rights reserved

4.6.4 N inlet tube, made by sealing the bottom end of a segment of polyethylene tubing, 75 mm long with
a 3,2 mm id, with a burner and then punching several holes in the sealed end with a 21-gauge needle which is
inserted through the second hole of the stopper. Alternatively, prepare a segment of polyethylene tubing
500 mm long with a 1,6 mm id in a similar manner which is secured in place in the stopper with a hole-through
septum.
4.6.5 Generator mount (optional), consisting of a segment of pipe, 64 mm long with a 1,3 m
...