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STANDARDSIST-TS CEN/TS 15479:20061DGRPHãþD
SIST EN 15479:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15479January 2009ICS 65.080Supersedes CEN/TS 15479:2006
English VersionFertilizers - Spectrophotometric determination of biuret in ureaEngrais - Détermination photométrique du biuret dansl'uréeDüngemittel - Spektrometrische Bestimmung von Biuret 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 15479:2009: ESIST EN 15479:2009
EN 15479:2009 (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 .6 8 Procedure .6 9 Calculation and expression of the result .7 10 Precision .7 11 Test report .8 Annex A (informative)
Results of the inter-laboratory tests .9 Bibliography . 10
SIST EN 15479:2009
EN 15479:2009 (E) 3 Foreword This document (EN 15479:2009) 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 15479:2006. 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 15479:2009
EN 15479:2009 (E) 4 1 Scope This European Standard specifies a method for the determination of biuret in urea. The method is applicable to urea and urea-based fertilizers. 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 In an alkaline medium in the presence of potassium sodium tartrate, biuret and bivalent copper form a violet cupric compound. The absorbance of the solution is measured at a wavelength of about 546 nm. 5 Reagents 5.1 General Use only reagents of recognized analytical grade and distilled or demineralized water, free from carbon dioxide and ammonia (grade 3 according to EN ISO 3696:1995). The quality of the water is particularly important in this determination. 5.2 Methanol 5.3 Sulfuric acid solution, c = approximately 0,05 mol/l. 5.4 Sodium hydroxide solution, c = approximately 0,1 mol/l. 5.5 Alkaline solution of potassium sodium tartrate In a graduated one-litre flask, dissolve 40 g of sodium hydroxide in 500 ml of water and leave to cool. Add 50 g of potassium sodium tartrate (NaKC4H4O6 4H2O). Make up to the mark and leave standing for 24 h before use. SIST EN 15479:2009
EN 15479:2009 (E) 5 5.6 Solution of copper sulfate In a graduated one-litre flask dissolve 15 g of copper sulfate (CuSO4 5H2O) in 500 ml of water. Make up to the mark. 5.7 Freshly prepared biuret standard solution In a 250 ml graduated flask, dissolve 0,250 g of pure biuret1 in water. Make up to 250 ml. 1 ml of this solution contains 0,001 g of biuret. 5.8 Indicator solution In a graduated 100 ml flask, dissolve 0,1 g of methyl red in 50 ml of 95 % ethanol, make up to 100 ml with water. Filter if any insoluble remain. This indicator is red in acid solution and yellow in alkaline solution. 6 Apparatus 6.1 Spectrometer or photometer With filters with a sensitivity and precision to permit measures of less than 0,5 % factor of transmission to be produced. The factor of transmission, T, is given by the following equation: JoJT= (1) The opacity, O, is given by the following equation: JJoO= (2) The absorbance, E, is given by the foll
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