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STANDARDSIST-TS CEN/TS 15476:20061DGRPHãþD
SIST EN 15476:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15476January 2009ICS 65.080Supersedes CEN/TS 15476:2006
English VersionFertilizers - Determination of nitric and ammoniacal nitrogenaccording to DevardaEngrais - Détermination de l'azote nitrique et ammoniacalselon DevardaDüngemittel - Bestimmung von Nitrat- undAmmoniumstickstoff nach DevardaThis 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 15476:2009: ESIST EN 15476:2009
EN 15476:2009 (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 .7 8 Procedure .7 9 Calculation and expression of the result . 10 10 Precision . 10 11 Test report . 10 Annex A (informative)
Results of the inter-laboratory tests . 12 Bibliography . 13
SIST EN 15476:2009
EN 15476:2009 (E) 3 Foreword This document (EN 15476:2009) 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 15476:2006. 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 15476:2009
EN 15476:2009 (E) 4 1 Scope This European Standard specifies a method for the determination of nitrate and ammoniacal nitrogen with reduction using Devarda alloy (modified for each of the variants a, b and c). The method is applicable to all nitrogenous fertilizers, including compound fertilizers, in which nitrogen is found exclusively in nitrate form or in ammoniacal and nitrate form. 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 inprovers — 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 Reduction of nitrates and nitrites to ammonia in a strongly alkaline solution by means of a metallic alloy composed of 45 % Al, 5 % Zn and 50 % Cu (Devarda alloy). Distillation of the ammonia and determination of the yield in a known volume of standard sulfuric acid; titration of the excess sulfuric acid by means of a standard solution of sodium or potassium hydroxide. 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 Diluted hydrochloric acid, mix one volume of ρ(HCl) = 1,18 g/ml with one volume of water.
5.3 Sulfuric acid (for variant a), c = 0,05 mol/l. 5.4 Sodium or potassium hydroxide solution (for variant a), carbonate free, c = 0,1 mol/l. 5.5 Sulfuric acid (for variant b, see NOTE 2 in 8.4), c = 0,1 mol/l.
SIST EN 15476:2009
EN 15476:2009 (E) 5 5.6 Sodium or potassium hydroxide solution (for variant b, see NOTE 2 in 8.4), carbonate free, c = 0,2 mol/l. 5.7 Sulfuric acid (for variant c, see NOTE 2 in 8.4), c = 0,25 mol/l. 5.8 Sodium or potassium hydroxide solution (for variant c, see NOTE 2 in 8.4), carbonate free, c = 0,5 mol/l. 5.9 Devarda alloy for analysis Powdered in such away that a mass fraction of 90 % to 100 % will pass through a sieve with apertures less than 0,25 mm square, a mass fraction of 50 % to 75 % will pass through a sieve with apertures of less than 0,075 mm square. Pre-packed bottles containing a maximum of 100 g are recommended. 5.10 Sodium hydroxide solution, 30 % of approximately ρ(NaOH) = 1,33 g/ml, ammonia free.
5.11 Indicator solutions 5.11.1 Mixed indicator Solution A: Dissolve 1 g of methyl red in 37 ml of sodium hydroxide solution c = 0,1 mol/l and make up to 1 l with water. Solution B: Dissolve 1 g of methylene blue in water and make up to 1 l. Mix one volume of A with two volumes of B. This indicator is violet in acid solution, grey in neutral solution and green in alkaline solution. Use 0,5 ml (10 drops) of this indicator solution. 5.11.2 Methyl red indicator solution Dissolve 0,1 g of methyl red in 50 ml of 95 % ethanol. Make up to 100 ml with water and filter if necessary. This indicator may be used (4 to 5 drops) instead of the preceding one. This indicator is red in acid solution and yellow in alkaline solution. 5.12 Ethanol, with a mass fraction of 95 % to 96 % ethanol. 5.13 Sodium nitrate, p. a. 6 Apparatus 6.1 Distillation apparatus Consisting of a round-bottomed flask of suitable capacity, connected to a condenser by a distillation tube with a splash head, additionally equipped with a bubble trap on the receiving flask to prevent any loss of ammonia. The type of apparatus recommended for this determination is reproduced, showing all the features of construction, in Figure 1. The equipment is made of borosilicate glass. SIST EN 15476:2009
EN 15476:2009 (E) 6 An automatic distillation apparatus may be used as well provided that the results are statistically equivalent. Dimensions in millimetres
Key 1 750 ml or 1 000 ml round-bottomed, long-necked flask with a bell mouth.
2 distillation tube with a splash head and a No 18 spherical joint at the issue
3 elbow tube with a No 18 spherical joint at the entrance, and a drip cone at the issue (a suitable rubber connection may be used instead of the spherical joint)
4 six-bulb condenser with an extension tube mounted on a rubber bung holding a bubble trap
5 750 ml receiving flask
6 bubble trap to prevent loss of ammonia Figure 1 — Distillation apparatus SIST EN 15476:2009
EN 15476:2009 (E) 7 6.2 Pipettes, capacity of 10 ml, 20 ml, 25 ml, 50 ml, 100 ml and 200 ml. 6.3 Graduated flask, capacity 500 ml. 6.4 Rotary shaker, 35 to 40 revolutions per minute. 7 Sampling and sample preparation Sampling is not part of the method specified in this document. A recommended s
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