kSIST FprEN 17759:2026

• Abstract:

  This document specifies a method for the determination of pH of a solution of ammonium nitrate fertilizer of high nitrogen content.; This document is only applicable to fertilizing product blends with high nitrogen content.; 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
• ICS: 65.080 - Fertilizers
• Technical Committee: KAT - Soil quality
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 03-Nov-2026
• Due Date: 22-Dec-2026
• 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 (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: FprEN 17759 - Inorganic fertilizers - Determination of pH of a solution of ammonium nitrate fertilizers of high nitrogen content

• Revises: SIST-TS CEN/TS 17759:2023 - Inorganic fertilizers - Determination of pH of a solution of ammonium nitrate fertilizers of high nitrogen content
• Effective Date: 01-Dec-2026

kSIST FprEN 17759:2026 is the Slovenian draft European standard for determining the pH of a solution prepared from ammonium nitrate fertilizers of high nitrogen content. It is published by SIST from prEN 17759 and is intended for laboratory testing of fertilizing product blends in which inorganic fertilizers are the main component. The document gives the test method, the reagents and equipment, the calibration and measurement steps, and the way to report the result.

What does kSIST FprEN 17759:2026 specify?

kSIST FprEN 17759:2026 specifies a method for measuring the pH of a solution of ammonium nitrate fertilizer of high nitrogen content. It applies to fertilizing product blends where inorganic fertilizers are the largest component by mass, by volume, or, for liquids, by dry mass.

Clause or annex	What it covers
Clause 1	Scope and applicability to fertilizing product blends
Clause 2	Normative references
Clause 3	Terms and definitions
Clauses 4-11	Principle, reagents, apparatus, sampling, procedure, result expression, precision, and test report
Annex A	Informative inter-laboratory study results

For blends made of several component types, the standard says the applicable method follows the component with the highest share. If the shares are equal, the user decides which standard to apply. In practice, this matters because the pH result can vary with matrix effects and interferences in mixed products.

What are the key requirements of kSIST FprEN 17759:2026?

kSIST FprEN 17759:2026 is built around a simple laboratory pH measurement, but it fixes the conditions closely so that results are comparable.

• Clause 4 - Principle: the pH of the ammonium nitrate solution is measured with a pH meter. This tells the laboratory to use an instrument-based pH determination, not an alternative acidity method.

• Clause 5 - Reagents: only reagents of recognized analytical grade are used, and the water must be distilled or demineralized and free from carbon dioxide. This matters because dissolved carbon dioxide can shift pH and distort the reading.

• Clause 5 - Buffer solutions: the meter is calibrated with buffer solution A or buffer solution B at 20 °C, and commercially available pH standard solutions may also be used. The standard also gives preparation instructions and says the buffers are kept in airtight vessels, which helps preserve their calibration value.

• Clause 6 - Apparatus: the pH meter must have glass and calomel electrodes or equivalent and a sensitivity of 0.05 pH unit. The balance, flask, and beaker capacities are also fixed so the sample and dilution are handled consistently.

• Clause 7 - Sampling and sample preparation: sampling is not part of the method, and sample preparation follows EN 1482-2. The text also warns that the laboratory sample should remain representative and unchanged during transport or storage.

• Clause 8 - Procedure: calibrate the meter at 20 °C ± 1 °C, add 100.0 mL of water to 10 g ± 0.1 g of sample, remove insoluble matter by filtering, decanting, or centrifuging, and measure the clear solution while stirring until the signal is stable. The temperature control matters because pH readings are temperature-sensitive.

• Clause 9 and Clause 11 - Reporting: report the result to the nearest 0.1 pH unit and state the temperature used, together with the sample identification, method reference, sampling details if known, and any non-standard operating details. This gives the buyer, producer, or auditor enough traceability to assess the result.

• Clause 10 and Annex A - Precision: the document includes repeatability and reproducibility limits derived from an inter-laboratory study. This helps laboratories judge whether two results are close enough to be considered consistent.

What terms does kSIST FprEN 17759:2026 define?

kSIST FprEN 17759:2026 uses terms from prEN 12944-1 and prEN 12944-2, and several practical terms are central to the method.

• Fertilizing product blend - a mix of at least two component types, such as fertilizers, liming materials, soil improvers, growing media, inhibitors, or plant biostimulants, used to decide whether this method applies.
• Inorganic fertilizers - the category that must be the highest share in the blend for this standard to apply.
• pH meter - the instrument used in Clause 4 and Clause 8 to measure the pH of the prepared solution.
• Buffer solution A / Buffer solution B - calibration solutions used at 20 °C to check and set the pH meter before measurement.
• Repeatability - the closeness of two results from the same laboratory, operator, equipment, and short time interval.
• Reproducibility - the closeness of two results obtained in different laboratories with different operators and equipment.

Who uses kSIST FprEN 17759:2026?

kSIST FprEN 17759:2026 is used by testing laboratories, fertilizer producers, and quality teams that need a consistent pH result for ammonium nitrate fertilizers of high nitrogen content. It is also relevant to buyers and inspectors who compare product specifications or check conformity. In practice, users apply it for sample preparation, meter calibration, routine testing, and reporting of laboratory results.

What changed in kSIST FprEN 17759:2026 from the previous edition?

kSIST FprEN 17759:2026 supersedes CEN/TS 17759:2022. The foreword lists these technical changes: the former Technical Specification has been adopted as a European Standard, the scope has been updated, the normative references have been updated, sampling and sample preparation have been revised, the use of a nitrogen stream during calibration and measurement has been removed, Clause 10 on precision and Annex A on inter-laboratory study results have been added, and the bibliography has been updated.

Which standards are used with kSIST FprEN 17759:2026?

kSIST FprEN 17759:2026 cites EN 1482-2 for general sample preparation, and prEN 12944-1 and prEN 12944-2 for the vocabulary used in the document. Clause 7.1 also points to EN 1482-1 as the recommended sampling method, while Clause 10 uses ISO 5725-1 and ISO 5725-2 to calculate repeatability and reproducibility from the inter-laboratory study.

What does the kSIST FprEN 17759:2026 document contain?

kSIST FprEN 17759:2026 contains the full laboratory method, from reagents and apparatus through calibration, measurement, and reporting. It also contains Clause 10 on precision, including repeatability and reproducibility limits, and Annex A with the inter-laboratory study results and statistical summary. The bibliography links the method to sampling and measurement-precision standards used alongside it.

SLOVENSKI STANDARD
oSIST prEN 17759:2026
01-april-2026
Anorganska gnojila - Določanje pH-vrednosti raztopine gnojil iz amonijevega
nitrata z veliko vsebnostjo dušika
Inorganic fertilizers - Determination of pH of a solution of ammonium nitrate fertilizers of
high nitrogen content
Anorganische Düngemittel - Bestimmung des pH-Wertes in einer Lösung mit
Ammoniumnitratdüngemitteln mit hohem Stickstoffgehalt
Engrais inorganiques - Détermination du pH d'une solution d'engrais à base de nitrate
d'ammonium à forte teneur en azote
Ta slovenski standard je istoveten z: prEN 17759
ICS:
65.080 Gnojila Fertilizers
oSIST prEN 17759:2026 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 17759:2026
oSIST prEN 17759:2026
DRAFT
EUROPEAN STANDARD
prEN 17759
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2026
ICS 65.080 Will supersede CEN/TS 17759:2022
English Version
Inorganic fertilizers - Determination of pH of a solution of
ammonium nitrate fertilizers of high nitrogen content
Engrais inorganiques - Détermination du pH d'une Anorganische Düngemittel - Bestimmung des pH-
solution d'engrais à base de nitrate d'ammonium à Wertes in einer Lösung mit
forte teneur en azote Ammoniumnitratdüngemitteln mit hohem
Stickstoffgehalt
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 17759:2026 E
worldwide for CEN national Members.

oSIST prEN 17759:2026
prEN 17759:2026 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 4
5.1 Distilled or demineralized water . 4
5.2 Buffer solution A . 4
6 Apparatus and equipment . 5
6.1 pH meter . 5
6.2 Graduated flask . 5
6.3 Beaker . 5
6.4 Balance . 5
6.5 Airtight vessel . 5
7 Sampling and sample preparation . 5
7.1 Sampling . 5
7.2 Sample preparation . 5
8 Procedure . 5
8.1 Calibration of the pH meter . 5
8.2 Determination . 5
9 Expression of the results . 5
10 Precision . 6
10.1 Inter-laboratory study . 6
10.2 Repeatability . 6
10.3 Reproducibility . 6
11 Test report . 6
Annex A (informative) Results of the inter-laboratory study . 7
A.1 Inter-laboratory study . 7
A.2 Statistical results . 7
Bibliography . 9

oSIST prEN 17759:2026
prEN 17759:2026 (E)
European foreword
This document (prEN 17759:2026) 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 will supersede CEN/TS 17759:2022.
prEN 17759:2026 includes the following significant technical changes with respect to
CEN/TS 17759:2022:
a) the CEN Technical Specification has been adopted as a European Standard;
b) update of Scope (Clause 1);
c) update of Normative references (Clause 2);
d) Sampling and sample preparation (Clause 7) has been updated;
e) the use of a nitrogen stream during calibration and measurement (8.1) has been removed;
f) Clause 10 (Precision) and Annex A including results of inter-laboratory study added;
g) update of Bibliography.
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 the
...