5314 International Standard (TSO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAR OPrAHM3AUWA nO CTAHAAPTW3AWM·ORGANISATION INTE RNATIONALE DE NORMALISATION ANsi Internat Doc Sc Fertilizers - Determination of ammoniacal nitrogen content -- Titrimetric method after distillation Engrais -- Dosage de I'azote ammoniacal -- Méthode titrimetrique apres distillation First edition - 1981-05-15 UDC 631.8 : 543.24 : 546.171.1 Ref. No. 1SO 5314-1981 (E) ISO 5314-1981 (E) Descriptors : fertilizers, chemical analysis, determination of content, nitrogen, ammoniacal nitrogen, volumetric analysis. Price based on 4 pages Copyright International Organization for Standardization 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 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. Fertilizers and soil conditioners, and was circulated to the member bodies in March 1978. Portugal Australia Ireland Brazil Israel Romania South Africa, Rep. of Canada Italy Kenya Czechoslovakia Spain Egypt, Arab Rep. of Mexico Thailand France Netherlands Turkey Germany, F. R. New Zealand United Kingdom Hungary Norway USSR India Philippines Venezuela iran Poland Yugoslavia No member body expressed disapproval of the document. @ International Organization for Standardization, 1981 Printed in Switzerland Copyright International Organization for Standardization ISO 5314-1981 (E) INTERNATIONAL STANDARD Fertilizers --- Determination of ammoniacal nitrogen content --- Titrimetric method after distillation Scope and field of application 4.4 Sodium hydroxide, standard volumetric solution, c(NaOH) = 0,20 mol/l.1) This International Standard specifies a titrimetric method, aftel distillation, for the determination of the ammoniacal nitrogen 4.5 Sulphuric acid, standard volumetric solution, content of fertilizers. c(H2S04) = 0,10 mol/1.1) The method is applicable only in the absence of urea or its 4.6 Indicator solution. derivatives, of cyanamide and of organic nitrogenous compounds. 4.6.1 Screened methyl red indicator, ethanolic solution. 2 References Mix 50 ml of a 2 g/l ethanolic solution of methyl red with 50 ml of 1 g/l ethanolic solution of methylene blue, or ISO/R 385, Burettes. 4.6.2 Methyl red indicator, ethanolic solution. Iso 641, Laboratory glassware - Interchangeable spherical ground joints. Dissolve 0,1 g of methyl red in 50 mi of 95 % (V/ V) ethanoi. Iso 648, Laboratory glassware - One-mark pipettes. 4.7 pH indicator paper, wide range. IS0 1042, Laboratory glassware One-mark volumetric flasks. 5 Apparatus 3 Principle 5.1 Distillation apparatus. Distilation of the ammonia from an alkaline solution, The components of the apparatus may be connected by means absorption in an excess of standard volumetric sulphuric acid of rubber bungs and tubing or by the use of ground glass joints. solution and back-titration with standard volumetric sodium hydroxide solution in the presence of methyl red or screened Ground glass joints should be held by spring clamps to ensure methyl red as indicator. that they are leak-tight. Rubber bungs and tubing shall be replaced when they begin to perish or show signs of wear. Reagents A suitable apparatus is illustrated in the figure and comprises : During the analysis, use only reagents of recognized analytical 5.1.1 Round bottomed flask, of nominal capacity 1 litre. grade and only distilled water or water of equivalent purity. 4.1 Ammonium sul