1、BSI Standards PublicationBS ISO 19242:2015Rubber Determination oftotal sulfur content by ionchromatographyBS ISO 19242:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 19242:2015.The UK participation in its preparation was entrusted to TechnicalCommittee PR
2、I/23, Test methods for rubber and non-blackcompounding ingredients.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication
3、. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 84719 6ICS 83.060Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30
4、June 2015.Amendments issued since publicationDate Text affectedBS ISO 19242:2015 ISO 2015Rubber Determination of total sulfur content by ion chromatographyCaoutchouc Dtermination de la teneur en soufre total par chromatographie ioniqueINTERNATIONAL STANDARDISO19242First edition2015-06-15Reference nu
5、mberISO 19242:2015(E)BS ISO 19242:2015ISO 19242:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, elect
6、ronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier
7、, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 19242:2015ISO 19242:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Principle 13.1 Combustion 13.1.1 Tubular furnace combustion method 13.1.2 Oxygen combustion flask method . 23.2 Det
8、ermination . 24 Reagents 25 Apparatus . 26 Procedure. 36.1 Preparation of sample solutions 36.1.1 Tubular furnace combustion method 36.1.2 Oxygen combustion flask method . 36.2 Determination of sulfate by ion chromatography 36.2.1 Setting up the ion chromatograph 36.2.2 Measuring calibration solutio
9、ns . 36.2.3 Measuring blank solutions and sample solutions . 37 Calculations 48 Precision . 49 Test report . 4Annex A (normative) Preparation of sample solutions by the tubular furnace combustion method 5Annex B (normative) Preparation of sample solutions by the oxygen combustion flask method . 8Ann
10、ex C (informative) Examples of conditions for ion chromatography 11Annex D (informative) Precision data from an interlaboratory test programme 12Bibliography .14 ISO 2015 All rights reserved iiiContents PageBS ISO 19242:2015ISO 19242:2015(E)ForewordISO (the International Organization for Standardiza
11、tion) 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
12、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.The procedures used to
13、develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
14、 ISO/IEC Directives, Part 2 (see www.iso.org/directives).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. Details of any patent rights identified duri
15、ng the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the mean
16、ing of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 45,
17、Rubber and rubber products, Subcommittee SC 2, Testing and analysis.iv ISO 2015 All rights reservedBS ISO 19242:2015ISO 19242:2015(E)IntroductionTitration methods using thorin, a toxic arsenic compound as a reagent, have been used to determine the total sulfur content in raw rubber and rubber compou
18、nds. In this International Standard the sulfur in a test piece is burnt and oxidized to sulfur dioxide, which is then absorbed into a hydrogen peroxide solution and converted to sulfuric acid for determination by ion chromatography.No hazardous reagents are required, thus improving the working envir
19、onment as well as being eco-friendly. In addition, ion chromatography is used worldwide for its simplicity and high accuracy. ISO 2015 All rights reserved vBS ISO 19242:2015BS ISO 19242:2015Rubber Determination of total sulfur content by ion chromatographyWARNING 1 Persons using this International S
20、tandard should be familiar with normal laboratory practice. This International 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 ensure compliance with any
21、 national regulatory conditions.WARNING 2 The use of this International Standard pre-supposes sufficient working knowledge of the principles and techniques of ion chromatography for the analyst to perform the operations described and interpret the results correctly.CAUTION Certain procedures specifi
22、ed 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 use.1 ScopeThis International Standard specifie
23、s a method for the determination of the total sulfur content of raw rubber and unvulcanized or vulcanized rubber compounds by ion chromatography following the preparation of a sample solution using either a tubular furnace combustion or an oxygen combustion flask method.The tubular furnace combustio
24、n method is applicable for rubbers with sulfur content less than 0,1 % as it is possible that the oxygen combustion flask method will not give sufficiently accurate results.The oxygen combustion flask method is not applicable to rubbers containing a metal salt that forms an insoluble metal sulfate,
25、such as barium sulfate.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documen
26、t (including any amendments) applies.ISO 3696, Water for analytical laboratory use Specification and test methodsISO 1795, Rubber, raw natural and raw synthetic Sampling and further preparative proceduresISO 4661-2, Rubber, vulcanized Preparation of samples and test pieces Part 2: Chemical tests3 Pr
27、inciple3.1 Combustion3.1.1 Tubular furnace combustion methodA test piece is burnt in an oxygen stream in a tubular furnace with an electrical heater. The sulfur in the test piece is oxidized to sulfur dioxide, which is absorbed into hydrogen peroxide solution and converted to sulfuric acid.INTERNATI
28、ONAL STANDARD ISO 19242:2015(E) ISO 2015 All rights reserved 1BS ISO 19242:2015ISO 19242:2015(E)3.1.2 Oxygen combustion flask methodA test piece is burnt in the presence of oxygen in a flask. The sulfur in the test piece is oxidized to sulfur dioxide, which is absorbed into hydrogen peroxide solutio
29、n and converted to sulfuric acid.3.2 DeterminationThe sulfate from either the tubular furnace combustion or the oxygen combustion flask method is quantitatively analysed by ion chromatography, and the result is converted to the total sulfur content of the original rubber sample.4 ReagentsUse only re
30、agents of recognized analytical grade and only water as specified in 4.1. The reagents for the tubular furnace combustion method are given in A.2. The reagents for the oxygen combustion flask method are given in B.2.4.1 Water, of grade 1 or higher as specified in ISO 3696.4.2 Sulfate stock standard
31、solution, of a commercial standard solution with a certified sulfate concentration, e.g. 1 000 mg/dm3of sulfate, traceable to national standards.Observe the manufacturers expiry date or recommended shelf-life.4.3 Sulfate calibration solutions, prepared by dilution of the sulfate stock standard solut
32、ion (4.2) with water (4.1).Prepare at least four solutions of different concentration of sulfate covering the expected concentration from the sample. The solutions shall be prepared every analytical day.4.4 Eluent solution, capable of eluting sulfate to a proper retention time in selected column.Fol
33、low the column manufacturers instructions. Some examples of eluent are shown in Annex C.5 Apparatus5.1 Balance, of accuracy to the nearest 0,1 mg.5.2 Apparatus for the tubular furnace combustion method, as specified in A.3.5.3 Apparatus for the oxygen combustion flask method, as specified in B.3.5.4
34、 Ion chromatograph, consisting of the pump to supply eluent, injection valve, column and conductivity detector specified as follows: Pump: capable of delivering a constant flow within the range of 0,1 cm3/min to 2,0 cm3/min; Injection valve: capable of injecting a constant volume of solution; Column
35、: filled with anion exchange resin suitable for resolving sulfates from other inorganic anions. Some examples are shown in Annex C; Suppressor: used for reducing the conductivity of high ionic eluent; Detector: for detecting conductivity.2 ISO 2015 All rights reservedBS ISO 19242:2015ISO 19242:2015(
36、E)An ion chromatograph fitted with a suppressor is suitable for sensitive analysis (see Figure 1). The suppressor is attached between the column and the detector. However, an ion chromatograph without a suppressor may also be selected (see Figure 2). For the conditions of these methods, see Annex C.
37、Figure 1 Example of basic ion chromatography system with suppressorFigure 2 Example of basic ion chromatography system without suppressor6 Procedure6.1 Preparation of sample solutions6.1.1 Tubular furnace combustion methodFollow the method specified in Annex A. Repeat the procedure to create two sol
38、utions for each sample.6.1.2 Oxygen combustion flask methodFollow the method specified in Annex B. Repeat the procedure to create two solutions for each sample.6.2 Determination of sulfate by ion chromatography6.2.1 Setting up the ion chromatographSet up the ion chromatograph in accordance with the
39、manufacturers instructions.6.2.2 Measuring calibration solutionsInject the calibration solutions in order of increasing concentration and measure the conductivity of sulfate peak area in each solution. Determine the correlation formula (calibration curve) by plotting the peak area as a function of c
40、oncentration by means of linear regression.6.2.3 Measuring blank solutions and sample solutionsInject the blank solutions and sample solutions (created in 6.1) to measure the peak area. Then determine the sulfate concentration of the blank CBand that of the individual sample solution CSby using the
41、calibration curve determined in 6.2.2. ISO 2015 All rights reserved 3BS ISO 19242:2015ISO 19242:2015(E)7 CalculationsCalculate the sulfur content of the sample in percentage from each value determined in 6.2.3. Average the two content values and round to the second decimal place, using the following
42、 formula:(),CC VWSB100032 0696 06100whereW is the mass of the test piece, in mg;CSis the sulfate concentration of the sample solution, in mg/dm3;CBis the sulfate concentration of the blank solution, in mg/dm3;V is the volume of the volumetric flask, in cm3;32,06 is the atomic weight of sulfur;96,06
43、is the molecular mass of sulfate.8 PrecisionSee Annex D.9 Test reportThe test report shall include the following particulars:a) sample details:1) a full description of sample;2) if appropriate, the brief preparation procedure of the test piece from the sample;b) test method:1) a reference to this In
44、ternational Standard (i.e. ISO 19242);2) the combustion method used: “tubular furnace combustion method” or “oxygen combustion flask method”;3) the method of ion chromatography used: suppressor or non-suppressor method;4) the column and eluent used;c) details of any procedures not specified in this
45、International Standard;d) the test results;e) the date(s) of the test.4 ISO 2015 All rights reservedBS ISO 19242:2015ISO 19242:2015(E)Annex A (normative) Preparation of sample solutions by the tubular furnace combustion methodA.1 GeneralThis annex specifies the preparation procedure of sample soluti
46、ons by the tubular furnace combustion method.A.2 Reagents and materialsA.2.1 Hydrogen peroxide solution of 500 g/g, prepared by diluting hydrogen peroxide of 30 % mass fraction solution with water to 500 g/g.A.2.2 Oxygen, of mass fraction 99,7 %.A.2.3 Argon, of mass fraction 99,98 %.A.2.4 Air, of ce
47、rtified quality in contamination and purity.NOTE Air is an alternative to the combustion gas of oxygen mixed with argon. The certification of the air quality can be judged by individual laboratories in so far as it does not affect the test result.A.3 ApparatusThe apparatus consists of combustion fur
48、nace, quartz tube, and absorbing vessel as shown in Figure A.1.A.3.1 Combustion furnace, with an electric heater capable of heating at a temperature of 1 000 C and maintaining the temperature for a certain period of time.A.3.2 Quartz tube, having heat-resistance enough to be heated at the maximum te
49、mperature (e.g. 1 000 C) by the electric heater and capable of holding a sample boat inside.A gas consisting of oxygen mixed with argon, or air which is supplied by the system, passes through the tube.A.3.3 Sample boat, made of quartz, ceramic, or platinum and capable of carrying a test piece.It shall have heat-resistance enough to be heated by the electric heater at the maximum temperature (e.g. 1 000 C).A.3.4 Absorption vessel, made of borosilicate glass with sufficient volume to allow the gas to bubble through
