CEN/TS 17765:2022

Organic and organo-mineral fertilizers - Determination of the biuret content by high-performance liquid chromatography (HPLC)

This document is applicable to fertilizing products, which are classified as PFC 1(A) and PFC 1(B) or the PFC 1(A) and PFC 1(B) component in PFC 7 of Regulation (EU) 2019/1009 [4]. However, the present method was not validated for blends.
This document specifies a method for the determination of the biuret content by high-performance liquid chromatography (HPLC) with UV detector. The method is applicable to organic and organo-mineral fertilizers containing urea.
Nowadays, there is a method standardized as EN 15479 that allows the determination of biuret in urea by spectrophotometric detection. Organic and organo-mineral fertilizers contain organic matter and other compounds apart from urea that would interfere in a spectrophotometric method. HPLC allows an accurate determination of biuret by separating it from possible interfering compounds [2] [3].

Organische und organisch-mineralische Düngemittel - Bestimmung des Biuretgehalts mittels Hochleistungs-Flüssigkeitschromatographie (HPLC)

Dieses Dokument ist für Düngeprodukte anzuwenden, die den Kategorien PFC 1(A) und PFC 1(B) zugeordnet oder als Komponente der Kategorien PFC 1(A) und PFC 1(B) in PFC 7 der Verordnung (EU) 2019/1009 [4] eingestuft sind. Das vorliegende Verfahren wurde jedoch nicht für Mischungen validiert.
Dieses Dokument legt ein Verfahren zur Bestimmung des Biuretgehalts mittels Hochleistungs-Flüssigkeitschromatographie (HPLC) mit UV Detektor fest. Das Verfahren ist für organische und organisch-mineralische Düngemittel, die Harnstoff enthalten, anzuwenden.
Heutzutage gibt es ein als EN 15479 genormtes Verfahren, das die Bestimmung von Biuret in Harnstoff durch spektrophotometrische Detektion ermöglicht. Organische und organisch-mineralische Düngemittel enthalten neben Harnstoff auch andere Verbindungen, die bei einem spektralphotometrischen Verfahren stören würden. Die HPLC ermöglicht eine genaue Bestimmung von Biuret, indem sie es von möglichen störenden Verbindungen trennt [2] [3].

Engrais organiques et organo-minéraux - Détermination de la teneur en biuret par chromatographie liquide à haute performance (HPLC)

Le présent document est applicable aux fertilisants qui sont classés dans les catégories PFC 1(A) et PFC 1(B) ou comme composants de PFC 1(A) et de PFC 1(B) dans la catégorie PFC 7 du Règlement (UE) 2019/1009 [4]. Toutefois, la présente méthode n’a pas été validée pour les mélanges.
Le présent document spécifie une méthode pour la détermination de la teneur en biuret par chromatographie en phase liquide haute performance (HPLC) avec un détecteur UV. La méthode est applicable aux engrais organiques et organo-minéraux contenant de l’urée.
De nos jours, il existe une méthode normalisée, l’EN 15479, qui permet de doser le biuret dans l’urée par détection spectrophotométrique. Cependant, les engrais organiques et organo-minéraux contiennent de la matière organique et des composés autres que l’urée qui interfèreraient en cas d’utilisation d’une méthode spectrophotométrique. La HPLC permet un dosage exact du biuret en le séparant des composés pouvant interférer [2] [3].

Organska in organsko-mineralna gnojila - Določevanje biureta s tekočinsko kromatografijo visoke ločljivosti (HPLC)

Ta dokument vzpostavlja metodologijo za določevanje vsebnosti biureta.

General Information

• Status: Published
• Publication Date: 05-Apr-2022
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 260 - Fertilizers and liming materials
• Drafting Committee: CEN/TC 260/WG 8 - Organic and organo-mineral fertilizers
• Current Stage: 9092 - Decision on results of review/2YR ENQ - revise - Review Enquiry
• Start Date: 03-Jun-2025
• Completion Date: 23-Sep-2025
• Directive: 2019/1009 - 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
• Mandate: M/564 - Fertilising products in support of Regulation (EU) 2019/1009
• Ref Project: SIST-TS CEN/TS 17765:2023 - Organic and organo-mineral fertilizers - Determination of the biuret content by high-performance liquid chromatography (HPLC)

Overview

CEN/TS 17765:2022 is a European Technical Specification developed by the Technical Committee CEN/TC 260 for fertilizers and liming materials. This standard specifies a high-performance liquid chromatography (HPLC) method with UV detection for determining the biuret content in organic and organo-mineral fertilizers containing urea. It applies primarily to fertilizing products in categories PFC 1(A) and PFC 1(B) under Regulation (EU) 2019/1009, but is not validated for fertilizer blends.

The presence of biuret, a condensation product formed during urea heating processes, is critical because high biuret concentrations can negatively affect plant growth. Unlike spectrophotometric methods (e.g., EN 15479) which can be interfered with by complex organic matter in fertilizers, the HPLC method outlined in CEN/TS 17765 provides accurate separation and quantification of biuret, overcoming such interference.

Key Topics

• Scope: Applicable to organic and organo-mineral fertilizers containing urea in PFC 1(A) and 1(B) categories; not validated for blends.
• Analytical Principle: Biuret is extracted using an aqueous acetonitrile solution and separated via reversed-phase HPLC. Quantification is achieved using UV detection at 195 nm and external calibration standards.
• Reagents & Apparatus:
  • HPLC grade acetonitrile (≥99.9%)
  • Biuret standards (≥97% purity)
  • Amino or aminopropyl chromatographic columns
  • UV detector and standard HPLC equipment including ultrasonic bath, filters, centrifuge, and micro-syringe.
• Procedure Highlights:
  • Sample preparation involves grinding, extraction with mobile phase (acetonitrile:water, 85:15 v/v), ultrasonic treatment, and filtration.
  • Calibration uses six standard solutions ranging from 0 to 200 mg/l of biuret for accurate curve creation.
  • HPLC is performed under specified conditions: 1.0 ml/min flow rate, 35 °C column temperature, and 10 µl injection volume.
• Calculations: Biuret content is calculated and expressed as a percentage of the fertilizer sample based on the calibration curve.
• Reporting: Must include sample identification, method reference, analytical results, sampling and analysis dates, and any deviations or incidents affecting results.

Applications

• Regulatory Compliance: Ensures fertilizer producers and laboratories comply with EU regulations regarding biuret content limitations in organic and organo-mineral fertilizers.
• Quality Control: Provides manufacturers with a reliable method to monitor biuret levels, which influences fertilizer safety and efficacy for crop growth.
• Research and Development: Supports R&D activities focused on fertilizer formulations by enabling precise measurement of biuret amid complex organic matrices.
• Environmental Safety: Helps prevent the detrimental environmental effects linked to excess biuret accumulation in soils by ensuring product conformity to safety thresholds.

Related Standards

• EN 15479: Spectrophotometric method for biuret determination specifically in urea; less suitable for complex organic fertilizers due to interference risks.
• ISO 18643: International standard describing an HPLC procedure akin to that in CEN/TS 17765 for urea-based fertilizers.
• Regulation (EU) 2019/1009: European legislative framework setting product function categories (PFCs) and safety requirements for EU fertilizing products.
• EN ISO 3696: Specifies water quality standards for laboratory use, ensuring reagent and solvent purity for accurate HPLC analysis.

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This technical specification not only enhances the accuracy and reliability of biuret quantification in organic and organo-mineral fertilizers but also contributes to sustainable agricultural practices by supporting regulatory compliance and product safety verification. The use of HPLC as described in CEN/TS 17765:2022 represents a significant improvement over traditional spectrophotometric methods, especially in samples with challenging organic content.

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2023
Organska in organsko-mineralna gnojila - Določevanje biureta s tekočinsko
kromatografijo visoke ločljivosti (HPLC)
Organic and organo-mineral fertilizers - Determination of the biuret content by high-
performance liquid chromatography (HPLC)
Organische und organisch-mineralische Düngemittel - Bestimmung des Biuretgehalts
mittels Hochleistungs-Flüssigkeitschromatographie (HPLC)
Engrais organiques et organo-minéraux - Détermination de la teneur en biuret par
chromatographie liquide à haute performance (HPLC)
Ta slovenski standard je istoveten z: CEN/TS 17765:2022
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TS 17765
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
April 2022
TECHNISCHE SPEZIFIKATION
ICS 65.080
English Version
Organic and organo-mineral fertilizers - Determination of
the biuret content by high-performance liquid
chromatography (HPLC)
Engrais organiques et organo-minéraux - Organische und organisch-mineralische Düngemittel -
Détermination de la teneur en biuret Bestimmung des Biuretgehalts
This Technical Specification (CEN/TS) was approved by CEN on 13 March 2022 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, 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, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 17765:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Reagents . 5
6 Apparatus . 6
7 Procedure . 6
7.1 Sampling . 6
7.2 Calibration solutions . 7
7.3 Preparation of the sample . 7
7.4 Extraction of the sample and preparation of the test solution. 7
7.5 HPLC conditions . 8
7.6 Preparation of the standard curve . 8
7.7 Determination of biuret in the test solutions . 8
8 Calculations . 9
9 Test report . 9
Bibliography . 10

European foreword
This document (CEN/TS 17765:2022) has been prepared by Technical Committee CEN/TC 260
“Fertilizers and liming materials”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN/CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to announce this Technical Specification: 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, Turkey and the United
Kingdom.
Introduction
Regulation (EU) 2019/1009 [4] lays down the rules on the making available on the market of EU
fertilizing products and the specific safety and quality requirements for the defined product function
categories (PFCs). Organic and organo-mineral fertilizers have been classified as PFC 1(A) and PFC 1(B).
This document defines test methods for the determination of the biuret content to be used for organic
and organo-mineral fertilizers in order to measure the compliance with the related requirement in
Regulation (EU) 2019/1009 [4].
When heating urea near or above its melting point (132 °C) during the manufacturing of urea, ammonia
slowly evolves and several different substances, including biuret, are formed. Excessively high
concentrations of biuret can have detrimental effects on plants growth.
1 Scope
This document is applicable to fertilizing products, which are classified as PFC 1(A) and PFC 1(B) or the
PFC 1(A) and PFC 1(B) component in PFC 7 of Regulation (EU) 2019/1009 [4]. However, the present
method was not validated for blends.
This document specifies a method for the determination of the biuret content by high-performance liquid
chromatography (HPLC) with UV detector. The method is applicable to organic and organo-mineral
fertilizers containing urea.
Nowadays, there is a method standardized as EN 15479 that allows the determination of biuret in urea
by spectrophotometric detection. Organic and organo-mineral fertilizers contain organic matter and
other compounds apart from urea that would interfere in a spectrophotometric method. HPLC allows an
accurate determination o
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