3357 NTERNATIONAL STANDARD TSO Sodium tripolyphosphate and sodium pyrophosphate for industrial use - Determination of total phosphorus(V) oxide content - Quinoline phosphomolybdate gravimetric method gravimetrique au phosphomolybdate de quinoleine First edition - 1975-09-01 ANsi Intarnat Doc Sect NO. Sas Feon. at ANST cNg.rCgpte SEP-0-2·19751 eoviLtr :04 40s mtormta. wrlo Ref. No. ISO 3357-1975 (E) UDC 661.833.456/.458 : 546.185-31 : 543.21 Descriptors : sodium pyrophosphate, sodium tripolyphosphate, chemical analysis, determination of content, phosphorus oxides, gravimetric analysis. Price based on 3 pages 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 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 1SO Council. ISO/TC 47, Chemistry, and circulated to the Member Bodies in April 1974. It has been approved by the Member Bodies of the following countries : India Spain Belgium Bulgaria Israel Switzerland Chile Italy Thailand Czechoslovakia Netherlands Turkey Egypt, Arab Rep. of New Zealand United Kingdom France Poiand Yugoslavia Germany Romania Hungary South Africa, Rep. of No Member Body expressed disapproval of the document. @ International Organization for Standardization, 1975 : PrintedinSwitzerland Copyright International Organization for Standardization Not for Resale ISO 3357-1975 (E) INTERNATIONAL STANDARD Sodium tripolyphosphate and sodium pyrophosphate for industrial use --- Determination of total phosphorus(V) oxide content --- Quinoline phosphomolybdate gravimetric method 1 SCOPE AND FIELD OF APPLICATION Ailow to stand for at least 12 h (for example, overnight) and filter through a sintered glass filter of porosity This International Standard specifies a gravimetric method grade P 10 (pore size index 4 to 10 μm). 'using quinoline phosphomolybdate for the determination of the total phosphorus(V) oxide content of sodium tripolyphosphate (pentasodium triphosphate) and sodium flask. pyrophosphate (tetrasodium diphosphate) for industrial use. 3.2.6 Add 280 ml of acetone to solution 3.2.5 and dilute to 1 000 ml with water 2 PRINCIPLE Do not keep this solution for more than 1 week. Store under the same conditions as solution 3.2.5. Hydrolysis of a test portion by prolonged boiling in the presence of hydrochloric acid. 4 APPARATUS Precipitation of phosphates in the form of quinoline phos- phomolybdate in the presence of acetone. Filtration, Ordinary laboratory apparatus and washing, drying and weighing of the precipitate. 4.1 Filter crucible, with sintered glass disk, porosity grade P 10 (pore size index 4 to 10 μm). 3 REAGENTS 4.2 Eiectric oven, capable of being controlled at During the analysis, use only reagents of recognized 250 ± 10 C. analytical reagent grade and onty distiled water or water of equivalent purity. 5 PROCEDURE 3.1 Hydrochloric acid, p approximately 1,19 g/ml, about WARNING -- Acetone is very flammable and must be 38 % (m/m) or approximately 12 N solution. handled onty inside a well-ventilated fume cupboard, in the absence of flames. 3.2 Citromolybdate reagent. 5.1 Test portion 3.2.1 Dissolve 70 g of sodium molybdate dihydrate Weigh, to the nearest 0,000 2 g, 1 g of the test sample (Na2Mo04.2H20) in 150 ml of water. taking care to avoid any gain or loss of moisture. 3.2.2 Dissolve60 gof citricacid monohydrate (CgHg07.H20) in 150 mi of water and add 85 mi of nitric 5.2 Blank test acid solution, p approximateiy 1,40 g/ml, about