FprEN 18319

• Abstract:

  This document specifies a method for the extraction and determination of phosphonates (P-PO3) in fertilizers, liming materials and inhibitors using ion chromatography and conductivity detection (IC-CD).; This document is applicable to fertilizing product blends, where the blend is a mix of at least two of the following components, fertilizers, liming materials, soil improvers, growing media, inhibitors and plant biostimulants, and where the following category, fertilizers, liming materials and inhibitors, is the highest % in the blend by mass or volume, or in the case of liquid form, by dry mass.; If fertilizers, liming materials and inhibitors 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: 24-Feb-2027
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 260 - Fertilizers and liming materials
• Drafting Committee: CEN/TC 260/WG 3 - Liming materials
• 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: oSIST prEN 18319:2026 - Fertilizers, liming materials and inhibitors - Determination of the phosphonates content by ion chromatography and conductivity detection (IC-CD)

Overview

FprEN 18319 is a CEN draft European standard for the determination of phosphonates content in fertilizers, liming materials and inhibitors using ion chromatography with conductivity detection (IC-CD). It specifies a practical laboratory method for water extraction followed by chromatographic measurement, supporting reliable analysis in the fertilizing products sector.

This standard is especially relevant for organizations working with EU fertilising products, quality control, compliance testing, and product verification. It also addresses fertilizing product blends, where the standard applies when fertilizers, liming materials and inhibitors represent the highest percentage of the blend by mass or volume, or by dry mass in liquid form.

A key purpose of FprEN 18319 is to help laboratories measure phosphonates consistently while reducing interference from other ions. The results are expressed as phosphorus bound in free water-soluble phosphonates (P-PO3), which aligns with regulatory and analytical needs.

Key Topics

• Analytical method

  • Water extraction of the test portion
  • Separation by ion chromatography
  • Detection by conductivity detection (IC-CD)

• Scope of materials

  • Fertilizers
  • Liming materials
  • Inhibitors
  • Selected fertilizing product blends

• Laboratory workflow

  • Sampling and sample preparation
  • Calibration with standard solutions
  • Measurement of test and blank solutions
  • Calculation of results on a dry matter basis

• Quality and precision

  • Guidance on repeatability and reproducibility
  • Use of control samples and calibration checks
  • Notes on possible interferences in complex matrices

• Regulatory context

  • Supports the control of unintentional phosphonate presence in line with Regulation (EU) 2019/1009

Applications

FprEN 18319 is valuable for professionals who need a robust phosphonates test method in agricultural and environmental product analysis. Typical applications include:

• Routine quality control in fertilizer laboratories
• Compliance testing for EU fertilising products
• Verification of product blends containing multiple matrix components
• Assessment of phosphonate contamination or residual presence
• Analytical support for manufacturers, importers, and regulatory bodies

Because the method is designed for well-equipped laboratories, it is particularly useful where accurate IC-CD analysis and documented traceability are required. The standard also includes test reporting expectations, helping improve consistency across laboratory workflows.

Related Standards

FprEN 18319 is connected to several CEN and ISO references used in sampling, vocabulary, precision, and related analytical methods:

• EN 1482-2:2024 - Fertilizers, liming materials and inhibitors - Sampling and sample preparation
• prEN 12944-1:2026 - Vocabulary - General terms
• prEN 12944-2:2026 - Vocabulary - Terms relating to fertilizers
• EN 12944-3:2025 - Vocabulary - Terms relating to liming materials
• EN 17246 - Determination of perchlorate by ion chromatography and conductivity detection
• EN 17705 - Determination of phosphonates in plant biostimulants
• ISO 5725-1 and ISO 5725-3 - Accuracy and precision of measurement methods

This standard is an important reference for phosphonate determination, fertilizer analysis, and European standardization in the fertilizing products domain.

SLOVENSKI STANDARD
01-april-2026
Gnojila, sredstva za apnjenje in inhibitorji - Določanje fosfonatov z ionsko
kromatografijo in detekcijo na osnovi prevodnosti (IC-CD)
Fertilizers, liming materials and inhibitors - Determination of the phosphonates content
by ion chromatography and conductivity detection (IC-CD)
Düngemittel, Kalkdünger und Hemmstoffe - Bestimmung des Phosphonatgehaltes
mittels Ionenchromatographie und Leitfähigkeitsdetektion (IC-CD)
Engrais, amendements minéraux basiques et inhibiteurs - Détermination de la teneur en
phosphonates par chromatographie ionique et détection conductimétrique (IC-CD))
Ta slovenski standard je istoveten z: prEN 18319
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
prEN 18319
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2026
ICS 65.080
English Version
Fertilizers, liming materials and inhibitors - Determination
of the phosphonates content by ion chromatography and
conductivity detection (IC-CD)
Engrais, amendements minéraux basiques et Düngemittel, Kalkdünger und Hemmstoffe -
inhibiteurs - Détermination de la teneur en Bestimmung des Phosphonatgehaltes mittels
phosphonates par chromatographie ionique et Ionenchromatographie und Leitfähigkeitsdetektion
détection conductimétrique (IC-CD) (IC-CD)
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 18319:2026 E
worldwide for CEN national Members.

prEN 18319:2026 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Reagents . 6
6 Apparatus . 6
7 Sampling and sample preparation . 7
8 Procedure . 7
8.1 Preparation of test solution - Water extraction . 7
8.2 Preparation of the calibration solutions . 7
8.3 Measurement . 8
8.3.1 Instrument conditions . 8
8.3.2 IC-CD measurement . 9
9 Calculation and expression of the results . 9
9.1 Integration of peaks . 9
9.2 Concentration of phosphonates in test sample solutions . 9
10 Precision . 10
10.1 Inter-laboratory study . 10
10.2 Repeatability . 10
10.3 Reproducibility . 10
11 Test report . 11
Annex A (informative) Separation of phosphonates from other interfering ions in a mixture
of standards . 12
Annex B (informative) Results of the inter-laboratory study . 13
Annex ZA (informative) Relationship of this European Standard and the essential
requirements of Regulation (EU) 2019/1009 making available on the market of EU
fertilising products aimed to be covered . 15
Bibliography . 16

prEN 18319:2026 (E)
European foreword
This document (prEN 18319:2026) 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.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
prEN 18319:2026 (E)
Introduction
This document describes a procedure for the extraction and measurement for the determination of
phosphonate (phosphite) in fertilizers, liming materials and inhibitors. It is based on a water extraction
of phosphonate (phosphite) followed by ion chromatography with conductivity detection (IC-CD).
The ion chromatography with conductivity detection (IC-CD) method can be used in well-equipped
analytical laboratories for the determination of different ions. In the field of fertilizing products, the
method is used and standardized for the determination of perchlorates in mineral fertilizers [1] and for
the determination of phosphonates in plant biostimulants [2]. The IC-CD method can determine ions
simultaneously.
According to Regulation (EU) 2019/1009 [3], phosphonates must not be intentionally added to any EU
fertilising product. Unintentional presence of phosphonates must not exceed 0,5 % (mass fraction). The
method described in this document was adapted to achieve this requirement and simultaneously to
reduce interferences from other co-extracted anions as much as possible.
The definition of phosphonates is not clearly stated in Regulation (EU) 2019/1009 [3] and to avoid any
misunderstanding, the results are expressed as a content of phosphorus (P) bound in the form of free
water-soluble phosphonates (P-PO ).
prEN 18319:2026 (E)
1 Scope
This document specifies a method for the extraction and determination of phosphonates (P-PO ) in
fertilizers, liming materials and inhibitors using ion chromatography and conductivity detection (IC-CD).
This document is applicable to fertilizing product blends, where the blend is a mix of at least two of the
following components, fertilizers, liming materials, soil improvers, growing media, inhibitors and plant
biostimulants, and where the following category, fertilizers, liming materials and inhibitors, is the highest
% in the blend by mass or volume, or in the case of liquid form, by dry mass.
If fertilizers, liming materials and inhibitors 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 1482-2:2024, Fertilizers, liming materials and inhibitors - Sampling and sample preparation - Part 2:
General sample preparation provisions
prEN 12944-1:2026, Fertilizers, liming materials and inhibitors — Vocabulary — Part 1: General terms
prEN 12944-2:2026, Fertilizers, liming materials and inibitors — Vocabulary — Part 2: Terms relating to
fertilizers
EN 12944-3:2025, 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 prEN 12944-1:2026,
prEN 12944-2:2026, and EN 12944-3:2025 and the following 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
3.1
phosphonate
salt derived from phosphonic acid (H PO )
3 3
4 Principle
A representative test portion of the sample is extracted with water. Phosphonate in the extract is
selectively separated from other compounds using ion chromatography (IC) and determined by a
conductivity detection (CD). External calibration is used for quantification of the amount of the
phosphonate.
prEN 18319:2026 (E)
WARNING 1 — Persons using this document should be familiar with usual laboratory practice. This
document does not purport to address all of the safety issues, if any, associated with its use. It is the
responsibility of the user to establish appropriate health and safety practices and to ensure compliance
with any national regulatory conditions.
WARNING 2 — It is absolutely essential that tests conducted according to this document are carried out
by suitably trained staff.
5 Reagents
All reagents shall be of recognized analytical grade. The concentration of phosphonate in the reagents
and water used shall be low enough not to affect the results of the determination.
5.1 Water with a specific conductivity not higher than 0,2 mS/m at 25 °C.
5.2 Phosphonate standard stock solution, mass concentration ρ = 1 000 mg/l is prepared by
(P-PO3)
dissolving sodium phosphite dibasic pentahydrate salt (M = 216,04 g/mol, purity ≥ 98 %). For
preparation the phosphonate standard stock solution 0,697 g ± 0,001 g is weighed, transferred to 100 ml
volumetric flask, fill with water (5.1) to final volume and mix thoroughly.
5.3 Phosphonate working standard solution, ρ = 100 mg/l is prepared from a standard stock
(P-PO3)
solution (5.2) by appropriate dilution with water (5.1). Pipette 10 ml of stock solution (5.2) to a 100 ml
volumetric flask, fill with water (5.1) to final volume and mix thoroughly.
5.4 Mobile phase, KOH cartridge for ion chromatography (commercially supplied). Concentration of
the KOH mobile phase is electrolytically generated in externally supplied water (5.1).
Different mobile phase may be used according to the instructions of the manufacturer of the column.
5.5 Chloride standard, ρ = 1 000 mg/l.
(Cl−)
5.6 Nitrate standard, ρ = 1 000 mg/l.
(NO3−)
5.7 Solution for checking chromatographic separation, ρ = 10 mg/l, ρ = 50 mg/l and
(P-PO3) (Cl−)
ρ = 50 mg/l is prepared by pipetting 1 ml of phosphonate standard stock solution (5.2), 5 ml of
(NO3−)
chloride standard (5.5), 5 ml of nitrate standard (5.6) to 100ml volumetric flask and fill to final volume
with water (5.1).
5.8 Sulfuric acid, ρ = 1,84 g/ml.
20(H2SO4)
5.9 Sulfuric acid solution, c = 0,56 mol/L, prepared by adding 30 ml of sulfuric acid (5.8) to 800 ml of
water in 1 000 ml volumetric flask. Addition is performed slowly with occasional swirling. Volumetric
flask is filled to the mark with water (5.1).
6 Apparatus
6.1 Common laboratory glassware and plastic.
6.2 Analytical balance, capable of weighing to the nearest ≤ 1 mg.
6.3 Shaker, rotary or horizontal shaker. Shaking shall prevent any settling of the sample during
extraction.
6.4 Extraction vessels, capacity 200 ml to 500 ml.
prEN 18319:2026 (E)
−1
6.5 Centrifuge (optional), for minimum 4 000 min (approx. 2 000 g).
6.6 Single use syringe filters (0,22 µm) or vials with filters, for filtering of test solutions prior to
analysis.
6.7 Ion chromatograph, with conductivity detection (IC-CD).
For higher signal/noise a supressed conductivity detector is preferred.
6.8 Chromatographic column for anion exchange, suitable for the selective separation of
phosphonates from other anions present in the sample.
It is recommended to use a guard column to prolong the lifetime of the analytical column.
Other columns recommended by a manufacturer may also be used, providing the results are comparable.
7 Sampling and sample preparation
Sampling is not part of the method specified in this document. Recommended sampling methods are
given in EN 1482-1 [4] and EN 1482-3 [5].
It is important that the laboratory receives a sample that is representative of both the product under
consideration and the given analysis. The sample should not have been damaged or changed during
transpor
...