kSIST FprEN 17758:2026
(Main)Fertilizers and liming materials - Determination of the chloride content by potentiometric titration
- 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
- Public Enquiry End Date
- 01-May-2026
- Technical Committee
- KAT - Soil quality
- Current Stage
- 5020 - Formal vote (FV) (Adopted Project)
- Start Date
- 03-Nov-2026
- Due Date
- 22-Dec-2026
kSIST FprEN 17758:2026 is the Slovenian adoption of the draft European Standard prEN 17758 from CEN. It specifies a potentiometric titration method for determining chloride content in organic fertilizers, organo-mineral fertilizers, inorganic fertilizers and liming materials. It also applies to certain fertilizing product blends when one of those categories is the dominant component, so the user can choose the correct method for mixed products.
What does kSIST FprEN 17758:2026 specify?
kSIST FprEN 17758:2026 specifies the analytical method, the reagents and equipment needed, the sample preparation and titration procedure, the calculation of results, and the precision data for the chloride determination. It is written for received laboratory samples and points readers to separate standards for sampling and general sample preparation.
| Annex | What it covers |
|---|---|
| Annex A | Informative results of the inter-laboratory study used for precision data |
The scope includes fertilizing product blends made from at least two components among fertilizers and liming materials, when the relevant category is the highest percentage by mass or volume, or by dry mass for liquid forms. If another category is dominant, the standard for that dominant category applies; if quantities are equal, the user decides which standard to use. The note in the scope warns that blends can give different analytical behavior because matrix interactions may affect the result.
What are the key requirements of kSIST FprEN 17758:2026?
kSIST FprEN 17758:2026 defines a titration method in which chloride is precipitated with silver nitrate in an acidified medium and the end point is found potentiometrically. In practice, the lab needs a suitable electrode setup and a stable titration curve to identify the equivalence point.
Principle and reagents
- Clause 4 sets out the measurement principle: chloride in water is titrated with standard silver nitrate and the voltage change is used to locate the end point. This matters because the method depends on electrical endpoint detection, not visual indicators.
- Clause 5 specifies the reagents, including chloride-free water, nitric acid, silver nitrate standard solution, polyvinyl alcohol (PVA) solution acidified with nitric acid, sodium chloride standard solution, and a sodium chloride control test sample. This keeps the titration medium controlled and supports calibration and verification.
Apparatus and sample preparation
- Clause 6 calls for standard laboratory glassware plus a potentiometric titration system, a silver or chloride-selective electrode, a reference electrode with chloride-free salt bridge, and a balance reading to 0.0001 g. This tells the lab what equipment must be available for a valid run.
- Clause 7 links sampling and sample preparation to EN 1482-2, while recommended sampling is given elsewhere and grinding is recommended for homogeneity. For organic and organo-mineral fertilizers, the document also allows centrifuging instead of filtration in the sample preparation step.
Titration, calibration and control
- Clause 8.2 requires calibration of the silver nitrate solution by titrating sodium chloride standard solution and calculating the titre factor from repeated measurements. This matters because the final result depends on the actual concentration of the titrant.
- Clause 8.3 sets the test portion and titration conditions: the sample solution is acidified to below pH 2 if needed, the aliquot must not contain more than 0.150 g chloride, and the silver nitrate consumption should stay within a practical titration range. This helps the analyst avoid biased or unstable measurements.
- Clause 8.4 requires a control test with freshly prepared sodium chloride solution before estimations. That gives a quick check that the method is working before sample results are reported.
Calculation, precision and reporting
- Clause 9 gives the calculation of chloride as a mass fraction in g/kg and the result is reported as chloride in the sample as received for analysis. The formula uses the titrant volume, titre factor, test portion mass and aliquot volume, so the laboratory must record those values carefully.
- Clause 10 provides precision data from an inter-laboratory study and defines repeatability and reproducibility limits. In practice, this is what a lab uses to judge whether duplicate results are consistent enough for routine control.
- Clause 11 lists the minimum contents of the test report, including sample identification, the method reference, the result, sampling details if known, the analysis date and any optional steps or incidents that could affect the outcome.
What terms does kSIST FprEN 17758:2026 define?
- Potentiometric titration - a titration where the endpoint is found from the voltage change between electrodes.
- Fertilizing product blend - a mix of at least two components among fertilizers and liming materials, where the dominant category determines which standard applies.
- Titre factor - the correction factor determined for the silver nitrate standard solution before sample titration.
- Control test - a verification run using a freshly prepared sodium chloride solution before sample determinations.
- Repeatability - the closeness of results obtained in the same laboratory under the same conditions.
- Reproducibility - the closeness of results obtained in different laboratories under different conditions.
Who uses kSIST FprEN 17758:2026?
kSIST FprEN 17758:2026 is used by analytical laboratories, fertilizer producers, liming material suppliers and quality control teams that need a chloride result for product release, specification checks or incoming goods control. It is also useful for buyers and technical staff who need to agree on one test method for fertilizing products and blends.
What changed in kSIST FprEN 17758:2026 from the previous edition?
kSIST FprEN 17758:2026 supersedes CEN/TS 17758:2022. The foreword states these changes: the technical specification has been adopted as a European Standard, the scope for fertilizing product blends has been updated, water has been added as a reagent, a centrifuge option has been added for test portion preparation of organic and organo-mineral fertilizers, precision data from the validation study have been included, Annex A has been added, and the normative references and bibliography have been revised.
Which standards are used with kSIST FprEN 17758:2026?
- EN 1482-2 - gives general sample preparation provisions, which Clause 7 uses directly.
- EN 12944-1 - provides general vocabulary for fertilizers, liming materials and inhibitors.
- EN 12944-2 - provides terms relating to fertilizers.
- EN 12944-3 - provides terms relating to liming materials.
- EN 1482-1 - gives general sampling provisions, cited as recommended sampling guidance.
- EN 1482-3 - gives sampling of static heaps, cited as recommended sampling guidance.
- EN 15958 - offers an alternative extraction-based sample preparation route mentioned in the procedure.
- EN 16195 - is a related chloride method for conditions without organic material.
- ISO 5725-2 and ISO 5725-3 - provide the statistical basis used to calculate repeatability and reproducibility.
What does the kSIST FprEN 17758:2026 document contain?
The document contains the full laboratory method from reagents and apparatus through to calculation and reporting. Clause 8 gives the titration workflow, including calibration, endpoint measurement and the control test, while Clause 9 provides the result expression. Clause 10 summarizes precision, Table 1 lists repeatability and reproducibility values for several sample types, and Annex A gives the inter-laboratory study statistics that support those figures.
Relations
- Effective Date
- 01-Apr-2026
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Frequently Asked Questions
kSIST FprEN 17758:2026 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Fertilizers and liming materials - Determination of the chloride content by potentiometric titration". This standard covers: 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.
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.
kSIST FprEN 17758:2026 is classified under the following ICS (International Classification for Standards) categories: 65.080 - Fertilizers. The ICS classification helps identify the subject area and facilitates finding related standards.
kSIST FprEN 17758:2026 has the following relationships with other standards: It is inter standard links to SIST-TS CEN/TS 17758:2023. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
kSIST FprEN 17758:2026 is associated with the following European legislation: EU Directives/Regulations: 2019/1009; Standardization Mandates: M/564, M/564 AMD 1, M/564 AMD 2. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
kSIST FprEN 17758:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 17758:2026
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
oSIST prEN 17758:2026 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 17758:2026
oSIST prEN 17758:2026
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.
oSIST prEN 17758:2026
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
oSIST prEN 17758:2026
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.
oSIST prEN 17758:2026
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
oSIST prEN 17758:2026
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
...