SIST EN 17705:2025

SLOVENSKI STANDARD
01-februar-2025
Nadomešča:
SIST-TS CEN/TS 17705:2023
Rastlinski biostimulanti - Določanje fosfonatov
Plant biostimulants - Determination of phosphonates
Pflanzen-Biostimulanzien - Bestimmung von Phosphonaten
Biostimulants des végétaux - Dosage des phosphonates
Ta slovenski standard je istoveten z: EN 17705:2024
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 17705
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2024
EUROPÄISCHE NORM
ICS 65.080 Supersedes CEN/TS 17705:2022
English Version
Plant biostimulants - Determination of phosphonates
Biostimulants des végétaux - Dosage des phosphonates Pflanzen-Biostimulanzien - Bestimmung von
Phosphonaten
This European Standard was approved by CEN on 26 August 2024.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17705:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Reagents . 5
6 Apparatus . 6
7 Sampling . 7
8 Procedure . 7
8.1 Sample preparation . 7
8.2 Water extraction . 7
8.3 Preparation of the calibration solutions . 7
8.4 Measurement . 8
8.4.1 Instrument conditions . 8
8.4.2 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 solutions . 9
10 Test report . 10
Annex A (informative) Separation of phosphonates from other interfering ions in a mixture
of standards . 11
Annex B (informative) Results of the inter-laboratory study . 12
B.1 Inter-laboratory tests . 12
B.2 Statistical results for determination of phosphonates . 12
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 . 14
Bibliography . 15

European foreword
This document (EN 17705:2024) has been prepared by Technical Committee CEN/TC 455 “Plant
Biostimulants”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2025, and conflicting national standards shall be
withdrawn at the latest by May 2025.
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 supersedes CEN TS 17705:2022.
In comparison with the previous edition no technical changes were applied in this document. The
following main editorial changes have been made:
— Introduction;
— Scope – text regarding blends changed;
— Annex B – results of the interlaboratory study added;
— Annex ZA added;
— Bibliography reordered.
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 relationship with EU Legislation, see informative Annex ZA, which is an integral part of this document.
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 implement this European Standard: 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 the United
Kingdom.
Introduction
The European Committee for Standardization (CEN) was requested by the European Commission (EC) to
draft European Standards or European Standardization deliverables to support the implementation of
Regulation (EU) 2019/1009 of 5 June 2019 [1] laying down rules on the making available on the market
of EU fertilising products (“FPR” or “Fertilising Products Regulation”).
This standardization request, presented as SR M/564 and relevant amendments, also contributes to the
Communication on “Innovating for Sustainable Growth: A Bio economy for Europe”. The interest in plant
biostimulants has increased significantly in Europe as a valuable tool to use in agriculture.
Standardization was identified as having an important role in order to promote the use of biostimulants.
The work of CEN/TC 455 seeks to improve the reliability of the supply chain, thereby improving the
confidence of farmers, industry, and consumers in biostimulants, and will promote and support
commercialisation of the European biostimulant industry.
This document describes a procedure for the extraction and measurement for the determination of
phosphonate (phosphite) in plant biostimulants. It is based on a water extraction of the phosphonate
(phosphite) followed by ion chromatography with conductivity detection (IC-CD).
The ion chromatography with a 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 [2]. The
IC-CD method can determine more ions simultaneously.
The other documents were studied as a basis for the preparation of this standard [3], [4], [5], [6], [7], [8].
The legislative limit for phosphonate content is 0,5 % (mass fraction) and 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 [1] 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 ).
The inter-laboratory study reflects the final statistical characteristics of the method for the determination
of phosphonates content in plant biostimulants. The results are given in Annex B (informative).
WARNING — 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.
IMPORTANT — It is absolutely essential that tests conducted according to this document are carried out
by suitably trained staff.
1 Scope
This document specifies a method for the extraction and determination of phosphonates (P-PO ) in plant
biostimulants using ion chromatography and conductivity detection (IC-CD).
This document is applicable to the blends of fertilizing products where a blend is a mix of at least two of
the following component EU fertilising products categories: Fertilizers, Liming Materials, Soil Improvers,
Growing Media, Inhibitors, Plant Biostimulants, and where the following category Plant Biostimulants is
the highest percentage in the blend by mass or volume, or in the case of liquid form by dry mass. If Plant
Biostimulants is not the highest percentage in the blend, the European Standard for the highest
percentage of the blend applies. In case a blend of fertilizing products is composed of components in equal
quantity or in case the component EU fertilising products used for the blend have identical formulations ,
the user decides which standard to apply.
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 17704:2024, Plant biostimulants — Determination of dry matter
EN 17702-1:2024, Plant biostimulants — Sampling and sample preparation — Part 1: Sampling
EN 17702-2:2024, Plant biostimulants — Sampling and sample preparation — Part 2: Sample preparation
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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.
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.

An example of such a blend is a product with two claimed functions consisting of a non-microbial plant
biostimulant and an organic fertilizer composed of 1kg/kg of plant biostimulant from seaweed.
5.1 Water with a specific conductivity not higher than 0,2 mS/m at 25 °C.
5.2 Phosphonate standard stock solution, ρ = 1 000 mg/l is prepared by dissolving
(P-PO3)
commercially available sodium phosphite dibasic pentahydrate salt (M = 216,04 mol/l, purity ≥ 98 %).
w
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 standard solution, ρ = 100 mg/l is prepared from a standard stock solution
(P-PO3)
(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 – commercially available.
(Cl−)
5.6 Nitrate standard, ρ = 1 000 mg/l – commercially available.
(NO3−)
5.7 Solution for checking chromatographic separation, ρ = 10 mg/l, ρ 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).
6 Apparatus
6.1 Common laboratory glassware and plastic.
6.2 Laboratory grinder, capable of grinding to a particle size less than 0,5 mm.
6.3 Analytical balance, capable of weighing to the nearest ≤ 1 mg.
6.4 Shaker, rotary or horizontal shaker. Shaking shall prevent any settling of the sample during
extraction.
6.5 Extraction vessels, capacity 200 ml to 500 ml.
−1
6.6 Centrifuge (optional), for minimum 4 000 min (approx. 2 000 g).
6.7 Single use syringe filters (0,22 µm) or vials with filters, for filtering of test solutions prior to
analysis.
6.8 Ion chromatograph, with conductivity detection (IC-CD).
For lower signal noise a supressed conductivity detector is preferred.
6.9 Chromatographic column for anion exchange, suitable for the selective separation of
phosphon
...