ISO/TS 9941:2003

Milk and canned evaporated milk — Determination of tin content — Spectrometric method

ISO/TS 9941|IDF/RM 160:2003 specifies a spectrometric method for the determination of the tin content of whole milk and canned evaporated milk. The detection limit of the method is 5 mg/kg.

Lait et lait concentré non sucré en boîte — Détermination de la teneur en étain — Méthode spectrométrique

General Information

• Status: Withdrawn
• Publication Date: 27-Nov-2003
• Withdrawal Date: 27-Nov-2003
• ICS: 67.100.10 - Milk and processed milk products
• Technical Committee: ISO/TC 34/SC 5 - Milk and milk products
• Drafting Committee: ISO/TC 34/SC 5 - Milk and milk products
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 19-Jul-2005

Relations

• Revised: ISO/TS 9941:2005 - Milk and canned evaporated milk — Determination of tin content — Spectrometric method
• Effective Date: 15-Apr-2008

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 9941
IDF/RM
160
First edition
2003-12-01

Milk and canned evaporated milk —
Determination of tin content —
Spectrometric method
Lait et lait concentré non sucré en boîte — Détermination de la teneur
en étain — Méthode spectrométrique




Reference numbers
ISO/TS 9941:2003(E)
IDF/RM 160:2003(E)
©
ISO and IDF 2003

---------------------- Page: 1 ----------------------
ISO/TS 9941:2003(E)
IDF/RM 160:2003(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. Neither the ISO Central
Secretariat nor the IDF accepts any liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies
and IDF national committees. In the unlikely event that a problem relating to it is found, please inform the ISO Central Secretariat at the
address given below.


©  ISO and IDF 2003
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 either ISO or IDF at the respective
address below.
ISO copyright office International Dairy Federation
Case postale 56 • CH-1211 Geneva 20 Diamant Building • Boulevard Auguste Reyers 80 • B-1030 Brussels
Tel. + 41 22 749 01 11 Tel. + 32 2 733 98 88
Fax + 41 22 749 09 47 Fax + 32 2 733 04 13
E-mail [e-mail] E-mail [e-mail]
Web www.iso.org Web www.fil-idf.org
Published in Switzerland

ii © ISO and IDF 2003 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 9941:2003(E)
IDF/RM 160:2003(E)
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 2.
The main task of technical committees is to prepare International Standards. 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.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of normative document:
 an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
 an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting
a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is
confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an
International Standard or be withdrawn.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TS 9941IDF/RM 160 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee
SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with AOAC
International. It is being published jointly by ISO and IDF and separately by AOAC International.

© ISO and IDF 2003 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/TS 9941:2003(E)
IDF/RM 160:2003(E)
Foreword
IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National
Committee in every member country. Every National Committee has the right to be represented on the IDF
Standing Committees carrying out the technical work. IDF collaborates with ISO and AOAC International in
the development of standard methods of analysis and sampling for milk and milk products.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the Action Teams and Standing Committees are circulated to the National Committees for voting.
Publication as an International Standard requires approval by at least 50 % of IDF National Committees
casting a vote.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
Standing Committee may decide to publish an other type of normative document which is called by IDF:
Reviewed method. Such a method represents an agreement between the members of a Standing Committee
and is accepted for publication if it is approved by at least 50 % of the committee members casting a vote. A
Reviewed method is equal to an ISO/PAS or ISO/TS and will, therefore, also be published jointly under ISO
conditions.
ISO/TS 9941|IDF/RM 160 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee
SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with AOAC
International. It is being published jointly by ISO and IDF and separately by AOAC International.
All work was carried out by the Joint ISO/IDF/AOAC Action Team Elements in milk and milk products, of the
Standing Committee on Minor components and characterization of physical properties, under the aegis of its
project leader, Dr M. Carl (DE).

iv © ISO and IDF 2003 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/TS 9941:2003(E)
IDF/RM 160:2003(E)
Introduction
This Technical Specification specifies a spectrometric method for the determination of the tin content in milk
and canned evaporated milk. Its detection limit is 5 mg/kg. Despite several attempts, the joint IDF/ISO/AOAC
International Action Team (JAT), Elements in milk and milk products, could not organize a collaborative study
with sufficient number of participating laboratories to conform to ISO 5725. Therefore, no precision figures for
repeatability and reproducibility could be established. However, since the method has been proven to be
reliable by at least three experienced laboratories, in particular with respect to its accuracy, it was proposed to
adopt the method as a Technical Specification rather than an International Standard. By publishing a
Technical Specification, it is expected that in future more laboratories will have experienced the method and
this so would make a full interlaboratory study and the publication of an International Standard possible.

© ISO and IDF 2003 – All rights reserved v

---------------------- Page: 5 ----------------------
ISO/TS 9941:2003(E)
TECHNICAL SPECIFICATION
IDF/RM 160:2003(E)

Milk and canned evaporated milk — Determination of tin
content — Spectrometric method
1 Scope
This Technical Specification specifies a spectrometric method for the determination of the tin content of whole
milk and canned evaporated milk. The detection limit of the method is 5 mg/kg.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
tin content
mass fraction of substances determined by the procedure specified in this Technical Specification
NOTE The tin content is expressed in milligrams per kilogram of sample.
4 Principle
The organic material is digested with a mixture of nitric acid and sulfuric acid. Water, hydrochloric acid and
sodium carbonate solution are added. Any interfering iron(III) ions are masked with thiourea solution and the
tin(IV) is complexed with quercetin. The absorbance of the yellow solution is measured spectrometrically at
the wavelength of maximum absorption (437 nm).
5 Reagents
Use only reagents of very pure analytical grade which, with the exception of the tin standard solution (5.11),
are free from tin.
5.1 Water, double-distilled, complying with the requirements of ISO 3696:1987, grade 2.
5.2 Ethanol (CH CH OH), with volume fraction about 96 %.
3 2
5.3 Diethyl ether [(C H ) O].
2 5 2
© ISO and IDF 2003 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO/TS 9941:2003(E)
IDF/RM 160:2003(E)
5.4 Sulfuric acid, concentrated, ρ (H SO ) = 1,84 g/ml.
20 2 4
5.5 Nitric acid, concentrated, ρ (HNO ) = 1,42 g/ml.
20 3
5.6 Hydrogen peroxide solution, ρ (H O ) = (1,099 to 1,103) g/ml.
20 2 2
Store the hydrogen peroxide solution in a refrigerator.
5.7 Hydrochloric acid solution, c(HCl) = 2,5 mol/l solution.
Dilute 221 ml of concentrated hydrochloric acid [ρ (HCl) = (1,17 to 1,18) g/ml] with water to 1 000 ml and mix.
20
5.8 Sodium carbonate solution, c(Na CO ) = 200 g/l.
2 3
Dissolve 200 g of anhydrous sodium carbonate in water. Dilute with water to 1 000 ml and mix.
5.9 Thiourea solution, c[CS(NH ) ] = 90 g/l.
2 2
Dissolve 45 g of thiourea in water. Dilute with water to 500 ml.
5.10 Quercetin solution, c(C H O ) = 0,75 g/l.
15 10 7
Dissolve 750 mg of quercetin (3,3',4',5,7-pentahydroxyflavone) in ethanol (5.2). Dilute with ethanol to 1 000 ml
and mix. Filter the quercetin solution through a filter paper. Store the solution in the dark for no longer than
one week.
5.11 Tin standard solution, c(Sn) = 1,000 g/l.
Dilute a commercially available preparation which contains exactly 1,000 g of Sn [e.g. Sn(IV), Titrisol
1)
No. 9929 is suitable] with the hy
...