SIST EN ISO 11212-3:1998

SLOVENSKI STANDARD
01-november-1998
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Starch and derived products - Heavy metals content - Part 3: Determination of lead
content by atomic absorption spectrometry with electrothermal atomization (ISO 11212-
3:1997)
Stärke und Stärkederivate - Schwermetallgehalt - Teil 3: Bestimmung des Bleigehaltes
durch Atomabsorptionsspektrometrie mit elektrothermischer Atomisierung
Amidons, fécules et produits dérivés - Teneur en métaux lourds - Partie 3: Détermination
de la teneur en plomb par spectrométrie d'absorption atomique avec atomisation
électrothermique (ISO 11212-3:1997)
Ta slovenski standard je istoveten z: EN ISO 11212-3:1997
ICS:
67.180.20 Škrob in izdelki iz njega Starch and derived products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

IS0
INTERNATIONAL
11212-3
STANDARD
First edition
1997-03-l 5
Starch and derived products - Heavy
metals content -
Part 3:
Determination of lead content by atomic
absorption spectrometry with electrothermal
atomization
Amidons, f&u/es et produits d&iv& - Teneur en m&aux lourds -
Parfie 3: DBtermination de la teneur en plomb par spectrom&rie
d ’absorption atomique avec atomisation Blectrothermique
Reference number
IS0 11212-3:1997(E)
IS0 11212-3: 1997(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
(IEC) 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 11212-3 was prepared by Technical Committee
I SO/IX 93, Starch (including derivatives and by-products).
IS0 11212 consists of the following parts, under the general title Starch
and derived products - Heavy metals content
- Par? 1: Determination of arsenic content by atomic absorption
spectrometry
- Part 2: Determination of mercury content by atomic absorption
spectrometry
- Part 3: Determination of lead content by atomic absorption
spectrometry with electrothermal atomization
- Part 4: Determination of cadmium content by atomic absorption
spectrometry with electrothermal atomization
Annex A of this part of IS0 11212 is for information only.
0 IS0 1997
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
Internet
central @ iso.ch
x.400 c=ch; a=400net; p=iso; o=isocs; s=central
Printed in Switzerland
ii
INTERNATIONAL STANDARD @ Is0 IS0 11212=3:1997(E)
Starch and derived products - Heavy metals content -
Part 3:
Determination of lead content by atomic absorption spectrometry with
electrothermal atomization -
1 Scope
This part of IS0 11212 specifies a method for the determination of the lead content of starch, including derivatives
and by-products, by atomic absorption spectrometry with electrothermal atomization.
The number of parameters for the procedure involved in the electrothermal atomization is far larger than in flame
atomization; it is thus impossible to propose a comprehensive method likely to ensure the attainment of satisfactory
results on all types of apparatus currently available. Each analyst should therefore optimize the conditions of use of
his/her own apparatus on the basis of general or particular instructions.
2 Definition
For the purposes of this part of IS0 11212, the following definition applies.
2.1 lead content: Quantity of lead determined in accordance with the conditions specified in this method and
expressed as lead (Pb), in micrograms per kilogram of the product as received.
3 Principle
Wet digestion of the organic matrix. Injection of an aliquot portion of digested sample, in the presence of a matrix
modifier, into the furnace of an electrothermal atomization atomic absorption spectrometer.
Measurement of the absorbance at a wavelength of 283,3 nm.
Determination of the concentration of lead in the sample by means of a calibration curve.
4 Reagents
Use only reagents of recognized analytical grade and distilled water or water of equivalent purity.
4.1 Nitric acid (pzO = I,38 g/ml).
4.2 Hydrogen peroxide, 30 % (V/v) solution

IS0 11212-3: 1997(E)
4.3 Matrix modifier, of the following composition:
Ammonium dihydrogen phosphate [(NH4)H2P04]
wl
Distilled water to make up to 1 000 ml
4.4 Lead standard solution, 1 g/l.
Standard solutions are commercially available at this concentration. These solutions may be prepared by weighing
and dissolving the salt or metal of known purity.
4.5 Calibration solutions
Before each series of measurements, prepare from the standard lead solution (4.4) at least five calibration solutions
covering the range of concentrations to be determined. 100 ml of each calibration solution shall contain 7,5 ml of
nitric acid (4.1) and 20 ml of the matrix modifier solution (4.3) if the latter is not distributed by the automatic injection
device.
5 Apparatus
All the glassware used shall be previously washed by means of suitable products (such as nitric acid) and rinsed
with distilled water to eliminate any trace of lead.
Use ordinary laboratory apparatus and, in particular, the following.
5.1 Digestion apparatus (see figure I), made of borosilicate glass and consisting of three elements terminating
with conical ground joints (5.1 .I to 5.1.3).
5.1 .l Soxhlet extraction tube, of capacity 200 ml, equipped with a stopcock and a lateral tube connected directly
to the flask (5.1.3).
5.1.2 Cooling apparatus, 35 cm long, connected to the top of the Soxhlet extraction tube (5.1 .I).
5.1.3 Round-bottom flask, of capacity 250 ml, connected to the lower part of the Soxhlet extraction tube (5.1 .I).
When the stopcock is open, the device is under reflux; when it is closed, the Soxhlet extraction tube (5.1 .I) retains
the condensed water and acid vapours.
5.2 Atomic absorption spectrometer, consisting of five elements (5.2.1 to 5.2.5).
5.2.1 High-resolution monochromator, allowing a 0,2 nm bandwidth slit.
5.2.2 Correcting device for non-specific absorption.
Measuring and photoelectric reception device, with a response time not exceeding about IO ms.
5.2.3
5.2.4 Detector and signal processing system, allowing recording of the maximum and/or integrated absorbance
signal.
5.2.5 Lead discharge lamp or lead hollow cathode lamp.
5.3 Ele
...