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STANDARDSIST-TS CEN/TS 15478:20061DGRPHãþD
SIST EN 15478:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15478January 2009ICS 65.080Supersedes CEN/TS 15478:2006
English VersionFertilizers - Determination of total nitrogen in ureaEngrais - Détermination de l'azote total dans l'uréeDüngemittel - Bestimmung von Gesamtstickstoff inHarnstoffThis European Standard was approved by CEN on 30 November 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2009 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15478:2009: ESIST EN 15478:2009
EN 15478:2009 (E) 2 Contents Page Foreword .3 1 Scope .4 2 Normative references .4 3 Terms and definitions .4 4 Principle .4 5 Reagents .4 6 Apparatus .5 7 Sampling and sample preparation . 10 8 Procedure . 10 9 Calculation and expression of the result . 11 10 Precision . 11 11 Test report . 12 Annex A (informative)
Results of the inter-laboratory tests . 13 Bibliography . 14
SIST EN 15478:2009
EN 15478:2009 (E) 3 Foreword This document (EN 15478:2009) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2009, and conflicting national standards shall be withdrawn at the latest by July 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes CEN/TS 15478:2006. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 15478:2009
EN 15478:2009 (E) 4
1 Scope This European Standard specifies a method for the determination of total nitrogen in urea. This method is applied exclusively to urea fertilizers which are nitrate free. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1482-2, Fertilizers and liming materials — Sampling and sample preparation — Part 2: Sample preparation EN 12944-1:1999, Fertilizers and liming materials and soil improvers — Vocabulary — Part 1: General terms EN 12944-2:1999, Fertilizers and liming materials and soil improvers — Vocabulary — Part 2: Terms relating to fertilizers
EN ISO 3696:1995, Water for analytical laboratory use — Specification and test methods (ISO 3696:1987) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12944-1:1999 and EN 12944-2:1999 apply. 4 Principle Urea is transformed quantitatively into ammonia by boiling in the presence of sulfuric acid. The ammonia thus obtained is distilled from an alkaline medium, the distillate being collected in an excess of standard sulfuric acid. The excess acid is titrated by means of a standard alkaline solution. 5 Reagents 5.1 General Use only reagents of recognized analytical grade and distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds (grade 3 according to EN ISO 3696:1995). 5.2 Kjeldahl tablets,
5 g/tablet containing 100 parts K2SO4 to 1 part selenium. SIST EN 15478:2009
EN 15478:2009 (E) 5 5.3 Sulfuric acid, concentrated (ρ20 = 1,84 g/ml). 5.4 Sodium hydroxide solution, approximately NaOH 500 g/l. 5.5 Sulfuric acid, c = 0,05 mol/l, to use for the blank test. 5.6 Sodium or potassium hydroxide solution, carbonate free, c = 0,1 mol/l, to use for the blank test. 5.7 Sulfuric acid, c = 0,5 mol/l. 5.8 Sodium or potassium hydroxide solution, carbonate free, c = 1,0 mol/l. 5.9 Indicator solutions 5.9.1 Mixed indicator Solution A: Dissolve 1 g of methyl red in 37 ml of 0,1 mol/l sodium hydroxide solution and make up to one litre with water. Solution B: Dissolve 1 g of methylene blue in water and make up to one litre. Mix one volume of A with two volumes of B. This indicator is violet in an acid solution, grey in a neutral solution and green in an alkaline solution; use 0,5 ml (10 drops). 5.9.2 Methyl red indicator solution Dissolve 0,1 g of methyl red in 50 ml of 95 % ethanol and make up to 100 ml with water. Filter if necessary. This indicator (4 or 5 drops) may be used instead of the preceding one. This indicator is red in acid solution and yellow in alkaline solution. 5.10 Anti-bump granules, for example pumice stone, washed in hydrochloric acid and calcined. 5.11 Urea, p. a. 6 Apparatus 6.1 Distillation apparatus Consisting of a round-bottomed flask of suitable capacity connected to a condenser by means of a splash head. The equipment is made of borosilicate glass. NOTE The different types of equipment recommended for this determination are reproduced showing all the features of construction in Figures 1, 2, 3, and 4. Automatic distillation apparatus may be used as well provided that the results are statistically equivalent. SIST EN 15478:2009
EN 15478:2009 (E) 6 Dimensions in millimetres
Key 1 round-bottomed, long-necked flask of 1 000 ml capacity
2 distillation tube with a splash head, connected to the condenser by means of a spherical joint (No 18) (the spherical joint for the connection to the condenser may be replaced by an appropriate rubber connection)
3 funnel with a polytetrafluoroethylene (PTFE) tap (6) for the addition of sodium hydroxide
4 six-bulb condenser with spherical joint (No 18) at the entrance, and joined
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