ISO INTERNATIONAL STANDARD 6293-2 First edition 1998-05-01 Petroleum products Determination of saponification number - Part 2: Potentiometric titration method Produits pétroliers Détermination de Iindice de saponification- Partie 2: Méthode par titrage potentiométrique ISO Reference number ISO 6293-2:1998(E) py IHS under lic itted without license from IHS Not for Resale ISO 6293-2:1998(E) Foreword ISO(theInternationalOrganizationforStandardization)isaworldwidefederationof national standardsbodies(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 liaison with isO, also take part in the work. isO collaborates closely with the International Electrotechnical Commission(lEC)onallmattersofelectrotechnicalstandardization. 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 ISO 6293-2 was prepared by Technical Committee ISO/TC 28, Petroleum products ana lubricants. This first edition, together with ISO 6293-1, cancels and replaces ISO 6293:1983, which has been technically revised. IsO 6293 consists of the following parts, under the general title Petroleum products - Determination of saponificationnumber: Part 1: Colour-indicator titration method Part 2: Potentiometric titration method Annex A forms an integral part of this part of ISO 6293. @ISO1998 nternational Organizationfor Standardizatior Casepostale56·CH-1211Geneve20·Switzerland Internet [email protected] X.400 C=ch; a=400net; p=iso; o=isocs; S=central Printed in Switzerland onal Organization for Standardizatior Not for Resale INTERNATIONAL STANDARD @ISO ISO 6293-2:1998(E) Petroleum products Determination of saponification number - Part 2: Potentiometric titration method WARNING - The use of this part of ISO 6293 may involve hazardous materials, operations and equipment. This part of IsO 6293 does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this part of Iso 6293 to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This part of isO 6293 specifies a method for the determination, by potentiometric titration, of the amount of determination by colour indicator titration. Compounds of sulfur, phosphorus, halogens and some other compounds react with the alkali and acids under the test conditions. NOTES 1 The results on used crankcase and turbine oils, and on oils containing the compounds above as additive constituents, should be interpreted with care, bearing in mind the possible higher values obtainable due to these additional reactions. 2 These extraneous materials include certain organic acids and most non-alkali soaps. The odour of hydrogen sulfide near the end of theback-titration step is an indication ofthe presence of certain reactive sulfur compounds,but other reactive sulfur A gravimetric determination of fatty acid content is an alternative procedure for the estimation of such compounds. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of IsO 6293. At the time of publication, the editions indicated were valid. All standards are subject to revision, and most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. Iso 3696:1987, Water for analytical laboratory use Specification and test methods. Iso 6293-1:1996, Petroleum products -Determination of saponification number — Part 1: Colour-indicator titration method. CopyrightInternationalOrganizationforStandardization 1 Not for Resale