CEN/TS 17705:2022

SLOVENSKI STANDARD
01-februar-2023
Rastlinski biostimulanti - Določevanje fosfonatov
Plant biostimulants - Determination of phosphonates
Pflanzen-Biostimulanzien - Bestimmung von Phosphonaten
Biostimulants des végétaux - Dosage des phosphonates
Ta slovenski standard je istoveten z: CEN/TS 17705:2022
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TS 17705
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
March 2022
TECHNISCHE SPEZIFIKATION
ICS 07.080
English Version
Plant biostimulants - Determination of phosphonates
Biostimulants des végétaux - Dosage des phosphonates Biostimulanzien für die pflanzliche Anwendung -
Bestimmung von Phosphonaten
This Technical Specification (CEN/TS) was approved by CEN on 3 January 2022 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

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, Turkey 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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 17705:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Reagents . 5
6 Apparatus . 6
7 Procedure. 6
7.1 Sample preparation . 6
7.2 Water extraction. 6
7.3 Preparation of the calibration solutions . 7
7.4 Measurement . 7
8 Calculation and expression of the results . 9
8.1 Integration of peaks . 9
8.2 Concentration of phosphonates in test solutions . 9
9 Test report . 10
Annex A (informative) Separation of phosphonates from other interfering ions in a mixture
of standards . 11
Bibliography . 12

European foreword
This document (CEN/TS 17705:2022) has been prepared by the Technical Committee CEN/TC 455 “Plant
biostimulants”, the secretariat of which is held by AFNOR.
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 has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association.
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 announce this Technical Specification: 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, Turkey and the United
Kingdom.
Introduction
This document was prepared by the experts of CEN/TC 455 “Plant Biostimulants”. 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 laying down rules on the making available on the market of
EU fertilizing products (“FPR” or “Fertilising Products Regulation”).
This standardization request, presented as M/564, also contributes to the Communication on “Innovating
for Sustainable Growth: A Bio economy for Europe”. The Working Group 4 “Other safety parameters”, was
created to develop a work program as part of this request. The technical committee CEN/TC 455 “Plant
Biostimulants” was established to carry out the work program that will prepare a series of standards. The
interest in 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.
The preparation of this document is based on the Fertilising Products Standardization Request (M/564)
to CEN by the European Commission and the European Free Trade Association concerning a development
of the methods for analysis of fertilizers in the framework of Regulation (EC) No 2019/1009.
This document describes 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 detector (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. The IC-CD
method can determine more ions simultaneously.
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 the Regulation 2019/1009 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-PO3).

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 also applicable to the blends of fertilizing products where plant biostimulants are the
main part of the blend. Otherwise, the Technical Specification for the main part of the blend applies.
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.
CEN/TS 17704, Plant biostimulants — Determination of dry matter
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
phosphonates
salts 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 detector (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 deionized 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 r(P-PO3) = 1 000 mg/l is prepared by dissolving
commercially available sodium phosphite dibasic pentahydrate salt (Mw = 216,04 mol/l, purity ≥ 98 %).
For preparation the phosphonate standard stock solution 0,697 ± 0,001 g is weighed, transferred to
100 ml volumetric flask, fill with deionized water (5.1) to final volume and mix thoroughly.
5.3 Phosphonate standard solution, r(P-PO3) = 100 mg/l is prepared from a standard stock solution
(5.2) by appropriate dilution with deionized water (5.1). Pipette 10 ml of stock solution (5.2) to a 100ml
volumetric flask, fill with deionized 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 deionized water (5.1).
Different mobile phase may be used according to the instructions of the manufacturer of the column.
−
5.5 Chloride standard r(Cl ) = 1 000 mg/l - commercially available.
−
5.6 Nitrate standard r(NO3 ) = 1 000 mg/l – commercially available.
−
5.7 Solution for checking chromatographic separation r(P-PO3) = 10 mg/l, r(Cl and
−
NO3 ) = 50 mg/l is prepared by pipetting 1 ml of phosphonate standard stock solution (5.2), 5 ml of
chloride standard (5.5), 5 ml of nitrate standard (5.6) to 100ml volumetric flask and fill to final volume
with deionized 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, accuracy ≤ 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 detector (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
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 Procedure
7.1 Sample preparation
Solid samples are milled using a laboratory grinder (6.2) and homogenized if necessary. Excessive heating
during the sample pretreatment should be avoided. Liquid samples are homogenized before weighing the
test portion.
7.2 Water extraction
Weigh a sample test portion of approximately 10 g to the nearest milligram into an extraction vessel and
add (100 ± 1) ml of deionized water (5.1). The tightly closed vessels are then placed in a shaker (6.4) and
samples are extracted for (60 ± 5) min. A blank solution is prepared following the same procedure as for
samples.
For highly water absorbing and gel forming samples, only 2 g of sample and 100 ml of deionized water
(5.1) is preferred for the extraction.
...