1572 International Standard (ISO INTERNATIONAL ORGANIZATION FOR STANDARDIZATIONMEAYHAPOAHAR OPFAHW3AUMA NO CTAHAAPTW3AUWW-ORGANISATION INTE RNATIONALE DE NORMALISATION Tea - Preparation of ground sample of known dry matter content Thé-Preparationd'un échantillonbroyede teneurenmatiere seche connue Second edition -1980-08-15 01572-1980 (E) UDC663.95:620.113 Ref.No.ISO 1572-1980 (E) Descriptors : agricultural products, tea, tests, test specimen conditioning, test specimens, determination, dry matter. Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards institutes (Iso member bodies). The work of developing Inter- national Standards is carried out through ISo technical committees. Every member body interested in a subject for which a technical committee has been set 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 by the ISo Council. International Standard ISO 1572 was developed by Technical Committee ISO/Tc 34, Agricultural food products. This second edition was submitted directly to the Iso Council, in accordance with clause 5.10.1 of part 1 of the Directives for the technical work of Is0. It cancels and replaces the first edition (i.e. ISo 1572-1975), which had been approved by the member bodies of the following countries : Australia Hungary Romania Brazil India South Africa, Rep. of Canada Iran Spain Chile Israel Sri Lanka Colombia Korea, Rep. of Thailand Czechoslovakia Netherlands Turkey Egypt, Arab Rep. of Poland United Kingdom France Portugal USSR The member body of the following country had expressed disapproval of the docu- ment on technical grounds : USA InternationalOrganizationforStandardization,1980 Printed in Switzerland ISO 1572-1980 (E) INTERNATIONALSTANDARD Tea - Preparation of ground sample of known dry matter content Scope and field of application 5.2Sample container, clean, dry, airtight,made of glass or other suitable material which has no action on the sample and This International Standard specifies a method of preparing a of such a size that it will be nearly completely filled by the ground sample of tea and of determining its dry matter content, ground sample. for use in analytical determinations which require the results to beexpressed onthe drybasis. 5.3 Weighing bottle, squat form, with airtight lid. 2 References 5.4 Constant-temperature oven, capable of being con trolled at 103 ± 2 °C. Iso565,Testsieves-Wovenmetalwireclothandperforated plate-Nominal sizes of apertures. 5.5 Desiccator, containing an efficient desiccant. ISo 1839, Tea -Sampling. 5.6 Analytical balance 3 Definition Sampling For the purpose of this International Standard, the following 6 1 definition applies : Sample the tea in accordance with IS0 1839. dry matter : The matter remaining when a ground sample of the product is heated to constant mass under the conditions Preparation of ground sample specified. Using the grinding mill (5.1), grind a small quantity of the sam- 4 Principle ple and reject it, then quickly grind an amount slightly greater than that required for the specified tests and for the determina- Grinding of the sample, and determination of the dry matter tion of drymatter content. content of the ground sample by heating a test portion in an If the moisture content is too high for satisfactory grinding of oven at 103 ± 2 °C to constant mass. the sample to the fineness specified in 5.1, it is necessary to pre-dry a portion of the sample to be ground, in an oven to a Apparatus sufficient degree of dryness. Carry out the grinding after the 5 pre-dried sample has been allowed to cool. Usual laboratory apparatus not otherwise specified, and the Transfer the grindings to the previously dri