1578 NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOHHAN OPrAHW3AS HO CTAHIAPTW3ALIWW-ORGANISATION INTERNATIONALE DE NORMALISATION Tea -- Determination of alkalinity of water-soluble ash Thé - Détermination de I'alcalinite des cendres solubles dans I'eau First edition -- 1975-12-01 ISO 1578-1975 (E) Ref. No. 1SO 1578-1975 (E) UDC 663.95 : 543.241 Descriptors : agricultural products, tea, chemical analysis, determination of content, alkalinity, ash content. Pricebased on 2pages Copyright international Oorganization for Standardization without license from IHS Not for Resale FOREWORD IsO (the International Organization for Standardization) is a worldwide federation of national standards institutes (IsO Member Bodies). The work of developing International Standards is carried out through SO Technical Committees. Every up 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. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards bythe ISO Council. Prior to 1972, the results of the work of the Technical Committees were published as isO Recommendations; these documents are now in the process of being transformed into International Standards. As part of this process, Technical Committee ISO/TC 34 has reviewed ISO Recommendation R 1578 and found it technically suitable for transformation. International Standard isO 1578 therefore replaces 1SO Recommendation R 1578-1970 to which it is technically identical. following countries : Australia India Spain Brazil Iran Sri Lanka Chile Israel Thailand Turkey Colombia Korea, Rep. of United Kingdom Czechoslovakia Poland U.S.A. Egypt, Arab Rep. of Portugal France U.S.S.R. Romania Hungary South Africa, Rep. of No Member Body expressed disapproval of the Recommendation. No Member Body disapproved the transformation of ISO/R 1578 into an International Standard. @ International Organozation for Standardization, 1975 Printed in Switzerland opyrightInnationalganizationfor Sandardizaio Not for Resale without license from IHS ISO 1578-1975 (E) INTERNATIONAL STANDARD Tea - Determination of alkalinity of water-soluble ash 1 SCOPE AND FIELD OF APPLICATION Carry out two determinations using the filtrate obtained determinations of water-soluble ash and from two This International Standard specifies a method for the water-insoluble ash. determination of the alkalinity of water-soluble ash of tea. 2 REFERENCES 7 EXPRESSIONOFRESULTS ISO 1572, Tea -- Preparation of ground sample of known dry matter content. 7.1 Method of calculation and formulae ISO 1575, Tea -- Determination of total ash. Express the alkalinity in terms of milliequivalents, i.e. of the number of millilitres of normal acid required per 100 g ISO 1576, Tea -- Determination of water-soluble ash and of ground sample (see ISO 1572), on the dry basis, or as a water-insoluble ash. percentage by mass of potassium hydroxide (KOH) in the ground sample, on the dry basis. 3 DEFINITION 7.1.1 The alkalinity of the water-soluble ash, expressed as For the purpose of this International Standard, the milliequivalents per 100 g of ground sample, on the dry following definition applies : basis, is given by the formula alkalinity of the water-soluble ash : Either the amount of 100100 V acid required to neutralize the aqueous extract of the total RS mo ash, or the amount of alkali equivalent to this acid, when determined under the conditions specified. where V is the volume, in millilitres, of O,1 N hydrochloric 4 PRINCIPLE acid solution required (see note below); Titration of the filtrate from the determination of mo is the mass, in grams, of the test portion of the water-soluble ash, with standard hydrochloric acid solution, ground sample used for the determination of total ash using methyl orange as indicator. (see