kSIST FprEN 18103:2025
(Main)Inorganic fertilizers - Determination of nutrient polymers nitrogen in the presence of other nitrogenous forms
Inorganic fertilizers - Determination of nutrient polymers nitrogen in the presence of other nitrogenous forms
This document specifies a method for the determination of nutrient polymers nitrogen in presence of the other forms of nitrogen in inorganic fertilizers.
The method is applicable to all fertilizers which do not contain interfering organic compounds.
NOTE Nutrient polymers are methylen-urea (MU), in liquid and in solid form.
Anorganische Düngemittel - Bestimmung von Nährstoff-Polymer-Stickstoff in Anwesenheit anderer stickstoffhaltiger Formen
Dieses Dokument legt ein Verfahren zur Bestimmung von Nährstoff-Polymer-Stickstoff in Anwesenheit anderer stickstoffhaltiger Formen in anorganischen Düngemitteln fest.
Das Verfahren ist anwendbar für alle Düngemittel, die keine störenden organischen Verbindungen enthalten.
ANMERKUNG Zu den Nährstoffpolymeren gehört Methylenharnstoff (MU, en: methylen-urea) in flüssiger und fester Form.
Engrais inorganiques - Détermination de l’azote des polymères nutritifs en présence d’autres formes azotées
Le présent document spécifie une méthode pour le dosage de l’azote des polymères nutritifs en présence des autres formes d’azote dans les engrais inorganiques.
La méthode est applicable à tous les engrais qui ne contiennent pas de composés organiques interférents.
NOTE Les polymères nutritifs sont le méthylène-urée (MU), sous forme liquide et solide.
Anorganska gnojila - Določanje dušika v polimerih hranil v prisotnosti drugih oblik dušika
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 18103:2024
01-julij-2024
Anorganska gnojila - Določanje dušika v polimerih hranil v prisotnosti drugih oblik
dušika
Inorganic fertilizers - Determination of nutrient polymers nitrogen in the presence of other
nitrogenous forms
Anorganische Düngemittel - Bestimmung von Nährstoff-Polymer-Stickstoff in
Anwesenheit anderer stickstoffhaltiger Formen
Ta slovenski standard je istoveten z: prEN 18103
ICS:
65.080 Gnojila Fertilizers
oSIST prEN 18103:2024 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 18103:2024
oSIST prEN 18103:2024
DRAFT
EUROPEAN STANDARD
prEN 18103
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2024
ICS 65.080
English Version
Inorganic fertilizers - Determination of nutrient polymers
nitrogen in the presence of other nitrogenous forms
Anorganische Düngemittel - Bestimmung von
Nährstoff-Polymer-Stickstoff in Anwesenheit anderer
stickstoffhaltiger Formen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 260.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 18103:2024 E
worldwide for CEN national Members.
oSIST prEN 18103:2024
prEN 18103:2024 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Sampling and sample preparation . 5
6 Procedure . 6
7 Test report . 11
Annex A (informative) Stannous chloride solution . 12
Annex B (informative) Overview of subclauses to determine the various nitrogen forms . 13
Bibliography. 14
oSIST prEN 18103:2024
prEN 18103:2024 (E)
European foreword
This document (prEN 18103:2024) has been prepared by Technical Committee CEN/TC 260 “Fertilizers
and liming materials”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
oSIST prEN 18103:2024
prEN 18103:2024 (E)
1 Scope
This document specifies a method for the determination of nutrient polymers nitrogen in presence of
the other forms of nitrogen in inorganic fertilizers.
The method is applicable to all fertilizers which do not contain interfering organic compounds.
NOTE Nutrient polymers are methylen-urea (MU), in liquid and in solid form, isobutylidenediurea (IBDU) and
crotonylidenediurea (CDU).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 1482-1, Fertilizers and liming materials — Sampling and sample preparation — Part 1: Sampling
EN 1482-2, Fertilizers and liming materials — Sampling and sample preparation — Part 2: Sample
preparation
EN 1482-3, Fertilizers and liming materials — Sampling and sample preparation — Part 3: Sampling of
static heaps
EN 12944-1, Fertilizers and liming materials and soil improvers — Vocabulary — Part 1: General terms
EN 12944-2, Fertilizers and liming materials and soil improvers — Vocabulary — Part 2: Terms relating
to fertilizers
EN 15562, Inorganic fertilizers — Determination of cyanamide nitrogen
EN 17864, Inorganic fertilizers — Determination of nitrogen content in IBDU (isobutylidenediurea) and
CDU (crotonylidenediurea)
ISO 19746:2017, Determination of urea content in urea-based fertilizers by high performance liquid
chromatography (HPLC)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12944-1 and EN 12944-2
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
4 Principle
4.1 General
The test sample is treated in different ways depending on the parameter to be determined.
4.2 Total nitrogen
4.2.1 Total nitrogen in the presence of nitrate nitrogen
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prEN 18103:2024 (E)
The test sample is mineralized by Kjeldahl digestion after reduction of nitrate nitrogen to ammonia
nitrogen with the aid of metallic iron and stannous chloride. The resultant ammonia is determined by a
titrimetric method.
4.2.2 Total nitrogen in the absence of nitrate nitrogen
The test sample is mineralized by Kjeldahl digestion. The resultant ammonia is determined by a
titrimetric method.
4.3 Nitrate nitrogen
By calculating the difference between the nitrogen determined by Kjeldahl digestion after reduction of
nitrate nitrogen to ammonia with the aid of metallic iron and stannous chloride and that determined by
Kjeldahl digestion after elimination in an acid medium of nitrate nitrogen with ferrous sulfate.
In both cases the resulting ammonia is determined by a titrimetric method.
4.4 Ammonia nitrogen
Ammonia nitrogen is determined by steam distillation after making the solution slightly alkaline. The
resulting ammonia is determined by a titrimetric method.
4.5 Urea nitrogen
Urea nitrogen is determined by high liquid performance chromatography (HPLC).
4.6 Cyanamide nitrogen
Cyanamide nitrogen is determined by precipitation as a silver compound; the nitrogen being
determined in the precipitate by the Kjeldahl method.
4.7 Isobutylidenediurea nitrogen (IBDU)
IBDU nitrogen is determined by HPLC.
4.8 Crotonylidenediurea nitrogen (CDU)
CDU nitrogen is determined by HPLC.
4.9 Methylen-urea nitrogen
Methylen-urea nitrogen is determined by calculation, subtracting the sum of all other nitrogen forms
from the total nitrogen.
5 Sampling and sample preparation
5.1 Sampling
Samples taken for quality control purposes shall be representative, as described in EN 1482-1. Sampling
of static heaps shall be performed according to EN 1482-3.
5.2 Sample preparation
The sample preparation for quality control purposes shall be performed according to EN 1482-2.
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prEN 18103:2024 (E)
6 Procedure
6.1 Part A: Determination of total, nitric, ammoniacal and cyanamide nitrogen
6.1.1 Reagents
Use only reagents of recognized analytical grade and distilled or de-mineralized water. The electrical
conductivity shall at least be < 0,5 mS/m (at 25 °C).
6.1.1.1 Sulfuric acid, density at 20 °C, ρ = 1,84 g/ml.
6.1.1.2 Acetic acid, 96 % to 100 %.
6.1.1.3 Iron powder, reduced with hydrogen.
6.1.1.4 Stannous chloride solutions.
Dissolve 25 g of SnCl 2H O in 100 ml of concentrated hydrochloric acid (6.1.1.13) and make up to
2 2
200 ml with water. The solution shall be prepared before and properly discharged after use.
To check the reducing power of stannous chloride, see Annex A.
6.1.1.5 Ferrous sulphate, crystalline, FeSO⋅7H O.
4 2
6.1.1.6 Digestion catalyst mixture.
Finely grind 1 000 g of potassium sulphate (K SO ) and 10 g of copper (II) sulphate pentahydrate
2 4
(CuSO⋅5H O). Commercial Kjeldahl tablets may be used.
4 2
6.1.1.7 Sodium hydroxide solution, aqueous solution of a mass fraction of about 30 %, free from
ammonia.
6.1.1.8 Standard solution of hydrochloric acid, molar concentration c = 0,1 mol/l.
6.1.1.9 Standard solution of sodium hydroxide, c = 0,1 mol/l, free from carbonates.
6.1.1.10 Mixed indicator.
Mix 50 ml of a 2 g/l ethanolic methyl red solution with 50 ml of a 1 g/l ethanolic methylene blue
solution. The colour of this indicator changes from lilac in acid medium, via grey at pH 5,4, to green in
alkaline medium.
Commercial mixed indicators for ammoniacal nitrogen may be used.
6.1.1.11 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.
6.1.1.12 Magnesium oxide.
6.1.1.13 Hydrochloric acid, concentrated (ρ = 1,18 g/ml)
6.1.2 Apparatus and equipment
Usual laboratory apparatus and, in particular, the following.
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prEN 18103:2024 (E)
6.1.2.1 Digestion block, equipped with digestion tubes equipped with a corrosive fumes suction
unit.
The digestion unit shall be placed under a fume hood.
6.1.2.2 Steam distillation unit, able to distil 300 ml to 350 ml in 5 min to 6 min, equipped with a
device to cut off the addition of the 30 % sodium hydroxide solution.
6.1.3 Total nitrogen
6.1.3.1 Total nitrogen in the presence of nitrate nitrogen
Weigh (to the nearest 0,1 mg) an amount of the test sample not exceeding 40 mg of total nitrogen.
Transfer the test sample into a digestion tube.
Add 0,5 g of reduced iron (6.1.1.3) and 50 ml of stannous chloride solution (6.1.1.4).
Shake the flask and leave it to stand for approximately 1 h, shacking manually every 10 minutes.
Proceed with the digestion described in 6.1.7 and the distillation (step A) described in 6.1.8.
6.1.3.2 Total nitrogen in the absence of nitrate nitrogen
Weigh (to nearest 0,1 mg) an amount of the test sample not exceeding 40 mg of total nitrogen.
Transfer the test sample into a digestion tube.
Proceed with the digestion described in 6.1.7 and the distillation (step A) described in 6.1.8.
6.1.4 Nitrate nitrogen
Weigh (with accuracy of 0,1 mg) an amount of the test sample not exceeding 40 mg of total nitrogen.
Mix the test sample in a digestion tube with 50 ml of water.
Add 5 g of ferrous sulphate (6.1.1.5) and 5 ml of sulfuric acid (6.1.1.1).
Proceed with the digestion described in 6.1.7 and the distillation (step A) described in 6.1.8.
The concentration of nitrate nitrogen is determined subtracting the content of N as determined in 6.1.4
from the content of N as determined in 6.1.3.1 (see Annex B).
6.1.5 Ammoniacal nitrogen
Weigh (to the nearest 0,1 mg) an amount of the test sample containing a maximum of 40 mg of
ammoniacal nitrogen. Mix the test sample in a distillation tube with water.
Proceed with the distillation described in 6.1.8, step B.
6.1.6 Cyanamide nitrogen
Weigh (to the nearest 0,1 mg) an amount of the test sample containing a maximum of 400 mg of
cyanamide nitrogen and transfer it into a 250 ml volumetric flask.
Add 150 ml of water and a few drops of methyl red (6.1.1.11). Make the solution acid by using acetic
acid (6.1.1.2). Add 15 ml of acetic acid in excess. Shake for approximately 2 h.
If necessary, reacidify the solution during the operation, using acetic acid. Make up to the volume with
water, mix, filter immediately through a dry filter into a dry receptacle and immediately transfer 25 ml
of the clear solution into a 250 ml beaker and precipitate the cyanamide nitrogen as a silver complex
according to EN 15562.
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prEN 18103:2024 (E)
Transfer wet filter and precipitate to a digestion tube and proceed with the digestion described in 6.1.7
and the distillation (step A) described in 6.1.8.
6.1.7 Digestion of the test solution
Add 10 g of the catalyst (6.1.1.6) to the digestion tube.
Add 20 ml of sulfuric acid (6.1.1.1) and mix thoroughly.
Heat gently until foam no longer is formed.
Increase the heat slowly: first the liquid darkens and then clears with the formation of a yellow-green
suspension. Continue heating for approximately 1 h after obtaining a clear solution, maintaining it at
boiling point.
Allow the flask to cool. Carefully add some water, swirl and cool again.
Transfer the digested sample into a distillation tube and proceed with the distillation described in 6.1.8,
...
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