SIST-TS CEN/TS 15475:2006
(Main)Fertilizers - Determination of ammoniacal nitrogen
Fertilizers - Determination of ammoniacal nitrogen
This document specifies a method for the determination of the ammoniacal nitrogen content in fertilizers. The method is applicable to all nitrogenous fertilizers, including compound fertilizers, in which nitrogen is found exclusively either in the form of ammonium salts, or ammonium salts together with nitrates.
The document is not applicable to fertilizers containing urea, cyanamide or other organic nitrogenous compounds.
Düngemittel - Bestimmung von Ammoniumstickstoff
Engrais - Détermination de l'azote ammoniacal
La présente Spécification Technique spécifie une méthode pour détermination de la teneur en azote ammoniacal dans les engrais. La méthode est applicable à tous les engrais azotés, y compris les engrais composés, dans lesquels l’azote se trouve exclusivement sous forme de sels d’ammonium ou de sels d’ammonium associés à des nitrates.
Le présent document ne s’applique pas aux engrais contenant de l’urée, de la cyanamide ou d’autres composés organiques azotés.
Gnojila – Določevanje amonijevega dušika
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2006
*QRMLOD±'RORþHYDQMHDPRQLMHYHJDGXãLND
Fertilizers - Determination of ammoniacal nitrogen
Düngemittel - Bestimmung von Ammoniumstickstoff
Engrais - Détermination de l'azote ammoniacal
Ta slovenski standard je istoveten z: CEN/TS 15475:2006
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL SPECIFICATION
CEN/TS 15475
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
September 2006
ICS 65.080
English Version
Fertilizers - Determination of ammoniacal nitrogen
Engrais - Détermination de l'azote ammoniacal Düngemittel - Bestimmung von Ammoniumstickstoff
This Technical Specification (CEN/TS) was approved by CEN on 24 June 2006 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, 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 STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15475:2006: E
worldwide for CEN national Members.
Contents Page
Foreword.3
1 Scope .4
2 Normative references .4
3 Terms and definitions .4
4 Principle.4
5 Reagents.4
6 Apparatus .6
7 Sampling and sample preparation.11
8 Procedure .11
9 Calculation and expression of the result .13
10 Precision.13
11 Test report .14
Annex A (informative) Results of the inter-laboratory tests .15
Bibliography .16
Foreword
This document (CEN/TS 15475:2006) has been prepared by Technical Committee CEN/TC 260 “Fertilizers
and liming materials”, the secretariat of which is held by DIN.
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 announce this CEN Technical Specification: Austria, Belgium, 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.
1 Scope
This Technical Specification specifies a method for the determination of the ammoniacal nitrogen content in
fertilizers. The method is applicable to all nitrogenous fertilizers including compound fertilizers, in which
nitrogen is found exclusively either in the form of ammonium salts or ammonium salts together with nitrates.
The document is not applicable to fertilizers containing urea, cyanamide or other organic nitrogenous
compounds.
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.
prEN 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
Displacement of ammonia by means of an excess of sodium hydroxide, distillation and determining the yield
of ammonia in a given volume of a standard sulfuric acid and titration of the excess 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 in 8.2)
c = 0,1 mol/l
5.6 Sodium or potassium hydroxide solution (for variant b, see NOTE in 8.2)
carbonate free, c = 0,2 mol/l
5.7 Sulfuric acid (for variant c, see NOTE in 8.2)
c = 0,25 mol/l
5.8 Sodium or potassium hydroxide solution (for variant c, see NOTE in 8.2)
carbonate free, c = 0,5 mol/l
5.9 Sodium hydroxide
30 %, of approximately ρ(NaOH) = 1,33 g/ml, ammonia free
5.10 Indicator solutions
5.10.1 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.
5.10.2 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.
5.11 Anti-bump granules (i. e. pumice stone, glass pearls)
washed in hydrochloric acid and calcined
5.12 Ammonium sulfate
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.
An automatic distillation apparatus may also be used, provided that the results are statistically equivalent.
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 at the issue to a glass extension tube by
means of a small rubber connection (when the connection to the distillation tube is effected by means of a rubber tube, the
spherical joint may be replaced by a suitable rubber bung)
5 500-ml-flask in which the distillate is collected
6 PTFE-tap (the tap may likewise be replaced by a rubber connection with a clip)
Figure 1 — Distillation apparatus 1
Dimensions in millimetres
Key
1 round-bottomed, short-necked flask of 1 000 ml capacity with a spherical joint (No 35)
2 distillation tube with a splash head, equipped with a spherical joint (No 35) at the entrance and a spherical joint
(No 18) at the issue, connected at the side to a funnel with a polytetrafluoroethylene (PTFE) tap (5) for the addition of
sodium hydroxide
3 six-bulb condenser with a spherical joint (No 18) at the entrance and joined at the issue to a glass extension tube by
means of a small rubber connection
4 500-ml-flask in which the distillate is collected
5 PTFE-tap
a
enlarged description
Figure 2 — Distillation apparatus 2
Dimensions in millimetres
Key
1 round-bottomed, long-necked flask of 750 ml or 1 000 ml capacity with, a bell mouth
2 distillation tube with a splash head and a spherical joint (No 18) at the issue
3 elbow tube with a spherical joint (No 18) at the entrance, and a drip cone (the connection to the distillation tube may
be effected by means of a rubber tube instead of a spherical joint)
4 six-bulb condenser joined at the issue to a glass extension tube by means of a small rubber connection
5 500-ml-flask in which the distillate is collected
Figure 3 — Distillation apparatus 3
Dimensions in millimetres
Key
1 round-bottomed, long-necked flask of 1 000 ml capacity with a bell mouth
2 distillation tube with a splash head and a spherical joint (No 18), at the issue, connected at the side to a funnel with a
polytetrafluoroethylene (PTFE) tap (5) for the addition of sodium hydroxide (a suitable rubber bung may be used instead of
the spherical joint; the tap may be replaced by a rubber connection with an appropriate clip)
3 six-bulb condenser with a spherical joint (No 18) at the entrance, joined at the issue, by a rubber connection, to a
glass extension tube (when the connection to the distillation tube is effected by means of a rubber tube, the spherical joint
may be replaced by a suitable rubber bung)
4 500-ml-flask for the collection of the distillate
5 PTFE-tap
Figure 4 — Distillation apparatus 4
6.2 Pipettes
capacity of 10 ml, 20 ml, 25 ml, 50 ml, 100 ml and 200 ml
6.3 Graduated flasks
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 sampling method is given in
prEN 1482-1.
Sample preparation shall be carried out in accordance with prEN 1482-2.
8 Procedure
8.1 Preparation of the solution
According to Table 1, Table 2 or Table 3, depending on the variant chosen, weigh to the nearest 0,001 g a
quantity of 5 g, 7 g, or 10 g of the prepared sample and transfer it into a 500-ml flask.
Add 50 ml of water and then 20 ml of hydrochloric acid (5.2). Shake. Leave undisturbed until the evolution of
carbon dioxide has ceased. Add 200 ml of water and shake for half an hour with the rotary shaker (6.4). Filter
through a filter into a 500-ml graduated flask and make up to the volume with water.
8.2 Analysis of the solution
According to the variant chosen, place in the receiving flask a measured quantity of standard sulfuric acid as
indicated in Table 1, Table 2 or Table 3. Add the appropriate quantity of the chosen indicator solution (5.10.1
or 5.10.2) and, if necessary, water in order to obtain a volume of at least 50 ml. The end of the extension tube
of the condenser shall be below the surface of the solution.
Transfer by precision pipette, according to the details given in Table 1, an aliquot portion of the clear solution,
into the distillation flask of the apparatus. Add water in order to obtain a total volume of about 350 ml, and
several grains of pumice in order to control the boiling.
Assemble the distillation apparatus and taking care to avoid any loss of ammonia, add to the contents of the
distillation flask 10 ml of concentrated sodium hydroxide solution (5.9) or 20 ml of the reagent in the cases
where one has used 20 ml hydrochloric acid (5.2) in order to dissolve the test sample. Gradually warm the
flask; avoid boiling vigorously. When boiling commences, distil at a rate of about 100 ml in 10 min to 15 min;
the total volume of distillate should be about 250 ml. The condenser shall be regulated so t
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