FprEN 17758

• Abstract:

  This document specifies a method for the determination of the chloride content in organic fertilizers, organo-mineral fertilizers, inorganic fertilizers and liming materials by potentiometric titration.; This document is applicable to fertilizing product blends, where a blend is a mix of at least two of the following components, fertilizers and liming materials, and where the following category, organic fertilizers, organo-mineral fertilizers, inorganic fertilizers or liming materials, is the highest % in the blend by mass or volume, or in the case of liquid form, by dry mass.; If organic fertilizers, organo-mineral fertilizers, inorganic fertilizers, or liming materials is not the highest % in the blend, the European Standard for the highest % of the blend applies. In case a fertilizing product blend is composed of components in equal quantity, the user decides which standard to apply.; NOTE Variations in analytical methods for fertilizing product blends can lead to differing results as some components or matrix interactions can affect the outcome. Validation procedures have shown that developed standard methods are robust and reliable across diverse product compositions, but possible interferences and unexpected results when analysing fertilizing product blends are possible.

• Status: Not Published
• Publication Date: 03-Feb-2027
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 260 - Fertilizers and liming materials
• Drafting Committee: CEN/TC 260/WG 7 - Chemical analysis
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 20-Aug-2026
• Due Date: 31-Aug-2027
• Completion Date: 20-Aug-2026
• Directive: Harmonized Standard2019/1009 - 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 17758:2026 - Fertilizers and liming materials - Determination of the chloride content by potentiometric titration

• Revises: CEN/TS 17758:2022 - Fertilizers and liming materials - Determination of the chloride content by potentiometric titration
• Effective Date: 01-May-2024

Overview

FprEN 17758: Fertilizers and Liming Materials - Determination of the Chloride Content by Potentiometric Titration is a European standard developed by CEN under the guidance of Technical Committee CEN/TC 260. This document specifies a reliable method for determining the chloride content in various fertilizers and liming materials, including organic, organo-mineral, inorganic fertilizers, and their blends, using potentiometric titration.

The procedure is applicable to a wide range of fertilizing products, including product blends where one component predominates by mass or volume or, for liquid products, by dry mass. The standard highlights the importance of robust analytical protocols for quality assurance in the fertilizer industry.

Key Topics

• Chloride Content Determination: The standard outlines a method based on potentiometric titration using a silver nitrate solution in an acidified medium, quantifying chloride ions through measurement of electrode potential.
• Applicability to Blends: The procedure can be used on blends containing fertilizers and liming materials, provided the dominant component is among those covered. If no clear majority exists, the user is allowed to select an appropriate standard.
• Equipment and Reagents: Guidance is given for preparing reagents and carrying out titration using calibrated titration systems and appropriate electrodes.
• Precision and Reproducibility: The standard is informed by inter-laboratory studies and details repeatability and reproducibility parameters, ensuring that results are consistent across qualified laboratories.
• Reporting Requirements: Clear instructions are provided for documenting test conditions, results, methodologies, and any deviations from prescribed procedures.

Applications

FprEN 17758 plays an essential role in several sectors:

• Fertilizer Manufacturing: Enables producers to verify chloride content, crucial for product quality and regulatory compliance.
• Quality Control Laboratories: Provides a standardized method for analyzing organic, organo-mineral, inorganic fertilizers, and liming materials, ensuring comparability of analytical results across batches and sites.
• Regulatory Bodies: Supports market surveillance and enforcement of fertilizer composition standards by providing a recognized and validated testing approach.
• Agricultural Trade: Assures clients and trading partners of the consistent chemical quality of fertilizers, strengthening transparency and trust in international markets.
• Blended Products: Facilitates accurate analysis even in complex blends of several fertilizing materials, supporting product development and diversification.

Related Standards

Several standards complement or are referenced by FprEN 17758:

• EN 1482-1 & EN 1482-2: General sampling and sample preparation methods for fertilizers, liming materials, and inhibitors.
• EN 12944 Series: Vocabulary and definitions relevant to fertilizers and liming materials.
• EN 15958: Methods for extraction of water-soluble phosphorus, with cross-applicability in sample preparation.
• EN 16195: Specific methods for determining chlorides in the absence of organic material.
• ISO 5725 (Parts 2 & 3): Guidelines for calculating repeatability and reproducibility for analytical methods.

Practical Value

Implementing FprEN 17758 ensures that organizations achieve:

• Consistent Measurement Results: Reduces variability in chloride determination through harmonized analytical procedures.
• Regulatory Compliance: Demonstrates conformity to EU fertilizer regulations and supports transparent product labeling.
• Product Safety and Efficacy: Accurate chloride assessment contributes to the effectiveness of fertilizers and soil amendments, leading to better crop outcomes and environmental stewardship.
• Market Confidence: Builds stakeholder confidence in the integrity and quality of fertilizing products through standardized testing.

By applying the methods described in FprEN 17758, stakeholders across the fertilizer value chain can enhance their quality assurance processes, regulatory adherence, and product reliability for both domestic and international markets.

SLOVENSKI STANDARD
01-april-2026
Gnojila in sredstva za apnjenje - Določanje klorida s potenciometrijsko titracijo
Fertilizers and liming materials - Determination of the chloride content by potentiometric
titration
Düngemittel und Kalkdünger - Bestimmung des Chloridgehaltes mittels
potentiometrischer Titration
Engrais et amendements minéraux basiques - Détermination de la teneur en chlorures
par titrage potentiométrique
Ta slovenski standard je istoveten z: prEN 17758
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
prEN 17758
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2026
ICS 65.080 Will supersede CEN/TS 17758:2022
English Version
Fertilizers and liming materials - Determination of the
chloride content by potentiometric titration
Engrais et amendements minéraux basiques - Düngemittel und Kalkdünger - Bestimmung des
Détermination de la teneur en chlorures par titrage Chloridgehaltes mittels potentiometrischer Titration
potentiométrique
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 17758:2026 E
worldwide for CEN national Members.

prEN 17758:2026 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 5
6 Apparatus and equipment . 5
7 Sampling and sample preparation . 6
7.1 Sampling . 6
7.2 Sample preparation . 6
8 Procedure . 6
8.1 Preparation of the test portion and the sample solution . 6
8.2 Calibration of the system (titre factor) . 6
8.3 Determination . 7
8.4 Control test . 7
9 Calculation and expression of the results . 7
10 Precision . 7
10.1 Inter-laboratory study . 7
10.2 Repeatability . 8
10.3 Reproducibility . 8
11 Test report . 9
Annex A (informative) Results of the inter-laboratory study . 10
Bibliography . 12

prEN 17758:2026 (E)
European foreword
This document (prEN 17758:2026) 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 CEN Enquiry.
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.
prEN 17758:2026 includes the following significant technical changes with respect to
CEN/TS 17758:2022:
— The CEN Technical Specification has been adopted as a European Standard;
— Scope (Clause 1) updated regarding the applicability to fertilizing product blends;
— Water as reagent has been included (5.1);
— The option to use a centrifuge for the preparation of test portion (8.1) of organic and organic-mineral
fertilizers added;
— The precision data (Clause 10) of the validation study included;
— Annex A including results of inter-laboratory study added;
— Normative references (Clause 2) and Bibliography revised.
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.
prEN 17758:2026 (E)
1 Scope
This document specifies a method for the determination of the chloride content in organic fertilizers,
organo-mineral fertilizers, inorganic fertilizers and liming materials by potentiometric titration.
This document is applicable to fertilizing product blends, where a blend is a mix of at least two of the
following components, fertilizers and liming materials, and where the following category, organic
fertilizers, organo-mineral fertilizers, inorganic fertilizers or liming materials, is the highest % in the
blend by mass or volume, or in the case of liquid form, by dry mass.
If organic fertilizers, organo-mineral fertilizers, inorganic fertilizers, or liming materials is not the highest
% in the blend, the European Standard for the highest % of the blend applies. In case a fertilizing product
blend is composed of components in equal quantity, the user decides which standard to apply.
NOTE Variations in analytical methods for fertilizing product blends can lead to differing results as some
components or matrix interactions can affect the outcome. Validation procedures have shown that developed
standard methods are robust and reliable across diverse product compositions, but possible interferences and
unexpected results when analysing fertilizing product blends are possible.
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
EN 12944-3, Fertilizers, liming materials and inhibitors — Vocabulary — Part 3: Terms relating to liming
materials
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12944-1, EN 12944-2 and
EN 12944-3 apply.
ISO and IEC maintain terminological 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 chlorides, dissolved in water, are precipitated in an acidified medium by a standard solution of silver
nitrate. The chloride concentration in the samples is quantified by potentiometric determination. To
detect the end point, the voltage between a reference electrode on the one hand and the silver electrode
or an ion selective electrode on the other hand, is tracked. This voltage depends on the logarithm of the
chloride ion activity. If it is plotted, in mV, on the ordinate and the silver nitrate solution, in ml, on the

Under revision. Stage at the time of preparation: prEN 12944-1:2026
Under revision. Stage at the time of preparation: prEN 12944-2:2026
prEN 17758:2026 (E)
abscissa, the point of inflection of the curve obtained in this manner is the equivalence point. Equivalent
methods of evaluation are permitted [4, 6].
5 Reagents
Use only reagents of recognized analytical grade.
5.1 Water, distilled or demineralized with a specific conductivity not higher than 0,2 mS/m at 25 °C,
free from chloride.
5.2 Nitric acid, substance concentration c = 16 mol/l.
5.3 Nitric acid solu
...