prEN 15478

Inorganic fertilizers - Determination of total nitrogen in urea, methylene-urea and urea formaldehyde

This document specifies a method for the determination of the content of total nitrogen in urea, methylene-urea and urea formaldehyde in their pure form in inorganic fertilizers.

Anorganische Düngemittel - Bestimmung des Gesamtgehalts an Stickstoff in Methylen-Harnstoff und Harnstoff-Formaldehyd

Dieses Dokument legt ein Verfahren zur Bestimmung des Gesamtstickstoffgehalts in Harnstoff, Methylenharnstoff und Formaldehydharnstoff in ihrer reinen Form in anorganischen Düngemitteln fest.

Engrais inorganiques - Dosage de l’azote total dans l’urée, le méthylène-urée et l’urée-formaldéhyde

Le présent document spécifie une méthode pour la détermination de la teneur en azote total dans l’urée, le méthylène-urée et l’urée-formaldéhyde sous leur forme pure dans les engrais inorganiques.

Anorganska gnojila - Določanje celotnega dušika v sečnini, metilenurei in urea formaldehidu

General Information

• Status: Not Published
• Publication Date: 28-Feb-2028
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 260 - Fertilizers and liming materials
• Drafting Committee: CEN/TC 260/WG 7 - Chemical analysis
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 26-Feb-2026
• Due Date: 13-Oct-2026
• Completion Date: 26-Feb-2026
• Directive: Not Harmonized2019/1009 - Regulation (EU) 2019/1009 of the European Parliament and of the Council of 5 June 2019 laying down rules on the making available on the market of EU fertilising products and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003 (Text with EEA relevance)
• Mandate: M/564 - Fertilising products in support of Regulation (EU) 2019/1009
• Mandate: M/564 AMD 1 - amending Implementing Decision C(2020) 612 as regards certain harmonised standards and standardisation deliverables, deadlines for their adoption and the duration of the validity of the standardisation request
• Mandate: M/564 AMD 2 - Commission Implementing decision amending Implementing Decision C(2020)612 as regards harmonised standards, the deadlines for the adoption of those standards and the duration of the validity of the standardisation request to the European Committee for Standardisation as regards the EU fertilising products in support of Regulation (EU) 2019/1009 of the European Parliament and of the Council
• Ref Project: oSIST prEN 15478:2026 - Inorganic fertilizers - Determination of total nitrogen in urea, methylene-urea and urea formaldehyde

Relations

• Revises: EN 15478:2009 - Fertilizers - Determination of total nitrogen in urea
• Effective Date: 21-Apr-2021

Overview

prEN 15478 is a draft European Standard developed by the European Committee for Standardization (CEN) under Technical Committee CEN/TC 260, “Fertilizers and liming materials.” This standard specifies a robust method for the determination of total nitrogen content in inorganic fertilizers containing urea, methylene-urea, and urea formaldehyde in their pure forms. Accurate nitrogen determination is critical for fertilizer quality control, regulatory compliance, and agronomic performance, as nitrogen is a key nutrient for plant growth.

Implementing this standard helps laboratories, fertilizer manufacturers, and regulatory authorities ensure uniformity in analytical procedures, leading to reliable and reproducible results across the European market and beyond.

Key Topics

• Scope: The method covers total nitrogen determination in pure urea, methylene-urea, and urea formaldehyde present in inorganic fertilizers.
• Analytical Principle: The process involves quantitative conversion of nitrogen into ammoniacal salt via digestion with sulfuric acid, followed by distillation and titration for precise nitrogen measurement.
• Sample Preparation: Adheres to referenced standards to ensure samples are representative and undamaged, crucial for valid results.
• Equipment and Reagents: Utilizes specialized distillation apparatus and high-purity reagents, emphasizing accurate, interference-free measurement.
• Procedure: Step-by-step guidance distinguishes approaches for urea versus methylene-urea and urea formaldehyde, covering digestion, distillation, and back titration.
• Quality Control: Includes requirements for blank and control tests to validate apparatus function and method accuracy.
• Result Calculation: Defines formulas to express total nitrogen as a percentage of the sample mass.
• Precision and Inter-laboratory Validation: Summarizes repeatability and reproducibility data, informed by inter-laboratory studies, ensuring reliability of the method.

Applications

prEN 15478 is highly valuable in the following practical contexts:

• Fertilizer Manufacturing: Ensures product specifications for nitrogen content are met, supporting both product labeling and internal quality management.
• Analytical Laboratories: Provides standardized guidance for nitrogen determination, enabling comparability of results across different labs and jurisdictions.
• Regulatory Compliance: Facilitates alignment with European regulations for fertilizer composition, assisting authorities in verification and enforcement.
• Agricultural Research: Enables accurate assessment of fertilizer formulations, supporting studies on nutrient management and environmental impact.
• Trade and Certification: Standardized nitrogen testing streamlines certification for both domestic and international trade, reducing technical barriers.

Related Standards

For a complete, consistent approach to fertilizer analysis and sampling, prEN 15478 should be used in conjunction with related standards, including:

• EN 1482-1 and EN 1482-2: Methods for sampling and sample preparation of fertilizers, liming materials, and inhibitors.
• EN 12944-1 and EN 12944-2: Terminology for fertilizers, liming materials, and inhibitors.
• ISO 5725-1 and ISO 5725-2: Guidelines on accuracy, repeatability, and reproducibility of measurement methods.

Adopting prEN 15478 as a reference for laboratory and regulatory procedures in the fertilizer industry strengthens analytical consistency, supports compliance, and assures trust in product quality across European and global markets.

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2026
Anorganska gnojila - Določanje celotnega dušika v sečnini, metilenurei in urea
formaldehidu
Inorganic fertilizers - Determination of total nitrogen in urea, methylene-urea and urea
formaldehyde
Anorganische Düngemittel - Bestimmung des Gesamtgehalts an Stickstoff in Methylen-
Harnstoff und Harnstoff-Formaldehyd
Engrais inorganiques - Dosage de l’azote total dans l’urée, le méthylène-urée et l’urée-
formaldéhyde
Ta slovenski standard je istoveten z: prEN 15478
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2026
ICS 65.080 Will supersede EN 15478:2009
English Version
Inorganic fertilizers - Determination of total nitrogen in
urea, methylene-urea and urea formaldehyde
Engrais inorganiques - Dosage de l'azote total dans Anorganische Düngemittel - Bestimmung des
l'urée, le méthylène-urée et l'urée-formaldéhyde Gesamtgehalts an Stickstoff in Methylen-Harnstoff und
Harnstoff-Formaldehyd
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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15478:2026 E
worldwide for CEN national Members.

Contents Page
European 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
8.1 Procedure for the determination of total nitrogen in urea . 10
8.1.1 Preparation of the solution . 10
8.1.2 Analysis of the solution . 10
8.1.3 Blank . 10
8.1.4 Control test . 11
8.2 Procedure for the determination of total nitrogen in methylene-urea and urea
formaldehyde . 11
8.2.1 Preparation of the solution . 11
8.2.2 Analysis of the solution . 11
8.2.3 Blank . 11
8.2.4 Control test . 11
9 Calculation and expression of the result . 12
9.1 Calculation and expression of the result of total nitrogen in urea . 12
9.2 Calculation and expression of the result of total nitrogen in methylene-urea and
urea formaldehyde . 12
10 Precision . 13
10.1 Precision of the method aiming to determine total nitrogen in urea . 13
10.1.1 Inter-laboratory study . 13
10.1.2 Repeatability . 13
10.1.3 Reproducibility . 13
10.2 Precision of the method aiming to determine total nitrogen in methylene-urea and
urea formaldehyde . 13
10.2.1 Inter-laboratory study . 13
10.2.2 Repeatability . 13
10.2.3 Reproducibility . 13
11 Test report . 14
Annex A (informative) Results of the inter-laboratory tests . 15
Annex B (informative) Results of the inter-laboratory study . 16
Bibliography . 18
European foreword
This document (prEN 15478:2026) has been prepared by Technical Committee CEN/TC 260 “Fertilizers
and liming materials”, the secretariat of which is held by DIN.
This is currently submitted to CEN Enquiry.
This document will supersede EN 15478:2009.
— The scope has been broadened by adding the determination of the content of total nitrogen in
methylene-urea and urea formaldehyde and the title has been adjusted accordingly;
— The method has been technically revised according to the broader scope;
— The statistical results relating to the inter-laboratory study of the determination of total nitrogen in
methylene urea and urea formaldehyde have been added (10.2 and Annex B).
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
1 Scope
This document specifies a method for the determination of the content of total nitrogen in urea,
methylene-urea and urea formaldehyde in their pure form in inorganic fertilizers.
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 1482-2, Fertilizers, liming materials and inhibitors — Sampling and sample preparation — Part 2:
General sample preparation provisions
EN 12944-1, Fertilizers, liming materials and inhibitors — Vocabulary — Part 1: General terms
EN 12944-2, Fertilizers, liming materials and inhibitors — Vocabulary — Part 2: Terms relating to
fertilizers
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
The nitrogen is transformed quantitatively into ammoniacal salt by boiling in the presence of sulfuric
acid. The ammoniacal solution thus obtained is distilled through 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
Use only reagents of recognized analytical grade and distilled or demineralized water, free from carbon
dioxide and all nitrogenous compounds, having an electrical conductivity of at least < 0,5 mS/m (at
25 °C).
5.1 Kjeldahl tablets.
5.1.1 5 g/tablet containing 100 parts K SO to 1 part selenium.
2 4
or, in alternative,
5.1.2 5 g of pure K SO in powder (recommended).
2 4
5.2 Sulfuric acid, concentrated (mass concentration ρ = 1,84 g/ml).
A revision is under preparation. Stage at the time of preparation: prEN 12944-1:2026
A revision is under preparation. Stage at the time of preparation: prEN 12944-2:2026
5.3 Sodium hydroxide solution, NaOH, mass fraction of 30 %.
5.4 Sulfuric acid standard solution, amount-of-substance concentration c = 0,05 mol/l (0,10 N/l), to
use for the blank test in the determination of total nitrogen in urea only.
5.5 Sulfuric acid standard solution, c = 0,25 mol/l (0,5 N/l).
5.6 Sulfuric acid standard solution, c = 0,5 mol/l (1,0 N/l).
5.7 Sodium or potassium hydroxide standard solution, carbonate free, c = 0,1 mol/l, to use for the
blank test in the determination of total nitrogen in urea only.
5.8 Sodium or potassium hydroxide standard solution, carbonate free, c = 0,5 mol/l.
5.9 Sodium or potassium hydroxide standard solution, carbonate free, c = 1,0 mol/l.
5.10 Indicator for ammonia nitrogen, ready for use.
5.11 Anti-bump granules, for example pumice stone, washed in hydrochloric acid and calcined.
5.12 Urea, analytical grade.
5.13 Melamine, analytical grade.
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 and titration apparatus may be used as well 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 (6)
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
...