ISO INTERNATIONAL STANDARD 7238 IDF 104 Second edition 2004-12-01 Butter Determination of pH of the serum Potentiometric method Beurre - Détermination du pH de la phase aqueuse - Methode potentiometrique Reference numbers ISO 7238:2004(E) [so IDF 104:2004(E) @ ISO and IDF 2004 ISO 7238:2004(E) IDF 104:2004(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 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. ISOandIDF2004 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, 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 [email protected] E-mail [email protected] Web www.iso.org Web www.fil-idf.org Published in Switzerland @ISO and IDF2004-All rights reserved ISO7238:2004(E) IDF104:2004(E) Contents Foreword. 1 Scope. 2 Normative references 3 Terms and definitions 4 Principle 5 Reagents 6 Apparatus 7 Sampling 8 Procedure.. 8.1 Testportion 8.2 Separationoftheserum. 8.3 Calibration of the pH-meter. 8.4 Determination ... 8.5 Cleaning the electrodes 9 Expression of results. 10 Precision 10.1 Repeatability 10.2 Reproducibility 11 Test report. Bibliography - All rights reserved ii IS0 7238:2004(E) IDF 104:2004(E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards IsO technical committees. Each member body interested in a subject for which a technical committee has 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. InternationalStandardsaredraftedinaccordancewiththerulesgivenintheISO/lECDirectives,Part2 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. rights. IsO shall not be held responsible for identifying any or all such patent rights. ISO 7238liDF 104 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, revision. Only editorial changes have been made. ISOand IDF2004-All rights reserved ISO7238:2004(E) IDF 104:2004(E) Foreword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committeeineverymembercountry.EveryNationalCommitteehastherighttoberepresentedontheIDF 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. 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 5o % of the National Committees casting a vote. ISO 7238|iDF 104 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5,