ISO/DIS 11853

DRAFT INTERNATIONAL STANDARD ISO/DIS 11853
ISO/TC 45/SC 2 Secretariat: SIS
Voting begins on: Voting terminates on:
2009-08-21 2010-01-21

INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION

Caoutchouc — Détermination de la teneur en magnésium du caoutchouc naturel brut et des produits en

In accordance with the provisions of Council Resolution 15/1993 this document is circulated in

Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué

To expedite distribution, this document is circulated as received from the committee secretariat.

ISO Central Secretariat work of editing and text composition will be undertaken at publication

Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du

secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au

THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE

IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT

INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO

RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH

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. The ISO Central Secretariat

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. In the

unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted

under the applicable laws of the user's country, neither this ISO draft nor any extract from it may be

reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, photocopying,

Requests for permission to reproduce should be addressed to either ISO at the address below or ISO's

Foreword ............................................................................................................................................................iv

1 Scope......................................................................................................................................................1

2 Normative References...........................................................................................................................1

3 Terms and definitions ...........................................................................................................................1

4 Principle.................................................................................................................................................2

5 Reagents ................................................................................................................................................2

6 Apparatus...............................................................................................................................................2

7 Sampling................................................................................................................................................3

8 Procedure...............................................................................................................................................3

8.1 Test portion............................................................................................................................................3

8.2 Preparation of test solution..................................................................................................................3

8.3 Preparation of calibration graph..........................................................................................................3

8.4 Spectrometric measurements..............................................................................................................4

8.5 Plotting the calibration graph ..............................................................................................................4

8.6 Determination ........................................................................................................................................4

8.7 Dilution ...................................................................................................................................................4

8.8 Blank determination..............................................................................................................................5

8.9 Number of determinations....................................................................................................................5

8.10 Expression of results............................................................................................................................5

9 Precision ................................................................................................................................................6

10 Test report..............................................................................................................................................6

Annex A (Informative) Method of standard additions ....................................................................................7

Annex B (Informative) Precision.......................................................................................................................8

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.

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 11853 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee

WARNING — Persons using this International Standard should be familiar with normal laboratory

practice. This standard does not purport to address all of the safety problems, if any, associated with

its use. It is the responsibility of the user to establish appropriate safety and health practices and to

CAUTION — Certain procedures specified in this International Standard may involve the use or

generation of substances, or the generation of waste, that could constitute a local environmental

hazard. Reference should be made to appropriate documentation on safe handling and disposal after

This International Standard specifies an atomic absorption spectrometric method for the determination of the

magnesium content of natural rubber latex concentrate, raw natural rubber and products made from natural

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

ISO 124, Natural rubber latex concentrates – Determination of total solids content

ISO 1795, Rubber, raw, natural and synthetic – Sampling and further preparative procedures

natural rubber latex from Hevea brasiliensis containing ammonia and/or other preservatives and which has

natural rubber usually in bales or packages, forming the starting material for the manufacturing of rubber

content of magnesium present in a sample of natural rubber latex concentrate, and in all forms of raw natural

A test portion is ashed at 550 ºC ± 25 ºC. The ash is dissolved in nitric acid. The solution is aspirated into an

atomic absorption spectrometer and the absorption is measured at a wavelength of 285.2 nm, using a

During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only

b) Dilute nitric acid (1.6% v/v) by carefully pipette 11,5 cm of the nitric acid (5.a) into a 1000 cm one-mark

volumetric flask (6.4) and dilute to the mark with distilled water or water of equivalent purity;

c) Standard magnesium stock solution, containing 1 g of Mg per cubic decimetre; Use a commercially

d) Standard magnesium solution, containing 10 mg of Mg per cubic decimetre. Carefully pipette 10 cm

of the standard magnesium stock solution (5.c) into a 1000 cm one-mark volumetric flask (6.4) dilute to

the mark with dilute nitric acid (5.b) and mix thoroughly. Prepare this solution preferably on the day of use.

6.1 Atomic absorption spectrometer, fitted with a burner fed with acetylene and air compressor to at least

60 kPa and 300 kPa, respectively, and also fitted with a magnesium hollow-cathode lamp as the magnesium

emission source. The instrument shall be operated in accordance with the manufacturer’s instructions for

6.3 Muffle furnace, capable of being maintained at a temperature of 550 ºC ± 25 ºC.

6.4 One-mark volumetric flasks, glass-stopper, of capacities 25 cm , 50 cm , 100 cm , 200 cm , 500 cm