SIST EN 17703:2025
(Main)Plant biostimulants - Determination of chromium(VI)
Plant biostimulants - Determination of chromium(VI)
This document specifies a method for verifying that hexavalent chromium (Cr(VI)) is not present in plant biostimulants.
This document is applicable to all types of plant biostimulants (solid and liquid) used in agriculture.
The method specified is suitable to quantify the chromium(VI) content in plant biostimulants down to 2 mg/kg.
The results obtained from this method are strictly dependent on the extraction conditions. Results obtained by using other extraction procedures (extraction solution, pH, extraction time, etc.) are not comparable with the results produced by the procedure specified in this document.
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: 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.
Pflanzen-Biostimulanzien - Bestimmung von Chrom(VI)
Dieses Dokument legt ein Verfahren fest, mit dem nachgewiesen werden kann, dass sechswertiges Chrom (Cr(VI)) nicht in Pflanzen-Biostimulanzien vorhanden ist.
Dieses Dokument ist anwendbar für alle Arten von Pflanzen-Biostimulanzien (in fester Form und in flüssiger Form), die in der Landwirtschaft eingesetzt werden.
Das festgelegte Verfahren ist geeignet, den Chrom(VI)-Gehalt in Pflanzen-Biostimulanzien ab 2 mg/kg quantitativ zu bestimmen.
Die mit dem beschriebenen Verfahren erzielten Ergebnisse sind streng von den Extraktionsbedingungen abhängig. Ergebnisse, die mit anderen Extraktionsverfahren (Extraktionslösung, pH Wert, Extraktionszeit usw.) erzielt wurden, sind nicht mit den Ergebnissen vergleichbar, die mit dem in diesem Dokument festgelegten Verfahren erzielt wurden.
Dieses Dokument ist für die Mischungen von Düngeprodukten anwendbar, in denen eine Mischung aus mindestens zwei der folgenden Komponenten-EU Düngeprodukten besteht: Düngemittel, Kalkdünger, Bodenverbesserungsmittel, Kultursubstrate, Hemmstoffe, Pflanzen-Biostimulanzien und wenn die folgende Kategorie Pflanzen-Biostimulanzien prozentual den höchsten Massen- oder Volumenanteil in der Mischung bzw., bei flüssiger Form, den höchsten Trockenmasseanteil aufweist. Wenn Pflanzen-Biostimulanzien nicht den höchsten prozentualen Anteil in der Mischung ausmachen, ist die für den höchsten prozentualen Anteil geltende Europäische Norm anwendbar. Falls eine Düngemittelmischung aus Komponenten gleicher Menge besteht oder falls die für die Mischung verwendeten Komponenten-EU Düngeprodukte identische Formulierungen haben, entscheidet der Anwender, welche Norm angewendet wird.
Biostimulants des végétaux - Dosage du chrome(VI)
Le présent document spécifie une méthode permettant de vérifier que le chrome hexavalent [Cr(VI)] n’est pas présent dans les biostimulants des végétaux.
Le présent document s’applique à tous les types de biostimulants des végétaux (solides et liquides) utilisés en agriculture.
La méthode spécifiée est adaptée à la quantification dans les biostimulants des végétaux de teneurs en chrome(VI) à partir de 2 mg/kg.
Les résultats obtenus avec cette méthode sont strictement tributaires des conditions d’extraction. Les résultats obtenus avec d’autres modes opératoires d’extraction (solution d’extraction, pH, durée d’extraction, etc.) ne sont pas comparables aux résultats acquis avec le mode opératoire spécifié dans le présent document.
Le présent document est applicable aux mélanges de fertilisants constitués d’au moins deux composants appartenant aux catégories de fertilisants UE suivantes : engrais, amendements minéraux basiques, amendements du sol, supports de culture, inhibiteurs, biostimulants des végétaux et, dans lesquels la catégorie Biostimulants des végétaux représente le pourcentage le plus élevé du mélange en masse ou en volume, ou dans le cas d’un liquide, en masse sèche. Si les biostimulants des végétaux ne représentent pas le pourcentage le plus élevé du mélange, la Norme européenne relative au composant représentant le pourcentage le plus élevé du mélange s’applique. Dans le cas où un mélange de fertilisants contient des composants en quantité égale ou dans le cas où les composants des fertilisants UE utilisés pour le mélange ont des formulations identiques, l’utilisateur décide quelle norme appliquer.
Rastlinski biostimulanti - Določanje kroma Cr(VI)
Ta dokument določa metodo, s katero se preverja neprisotnost šestvalentnega kroma (Cr(VI)) v rastlinskih biostimulantih.
Ta dokument se uporablja za vse vrste rastlinskih biostimulantov (trdne in tekoče), ki se uporabljajo v kmetijstvu. Metoda je primerna za kvantifikacijo vsebnosti kroma (VI) v rastlinskih biostimulantih do vrednosti najmanj 2 mg/kg.
Rezultati te metode so strogo odvisni od pogojev ekstrakcije. Rezultati, pridobljeni z drugimi postopki ekstrakcije (ekstrakcijska raztopina, pH, čas ekstrakcije ipd.), niso primerljivi z rezultati, pridobljenimi s postopkom, opisanim v tem dokumentu.
Ta dokument se uporablja za mešanice sredstev za gnojenje, ki vsebujejo najmanj dve od naslednjih kategorij sredstev za gnojenje EU: gnojila, sredstva za apnenje tal, rastni substrati, inhibitorji in rastlinski biostimulanti, pri čemer rastlinski biostimulanti predstavljajo največji masni ali prostorninski odstotek mešanice ali, v primeru tekoče oblike, odstotek suhe mase. Če rastlinski biostimulanti ne predstavljajo največjega odstotka v mešanici, se uporablja evropski standard za največji odstotek mešanice. Če vsebuje mešanica sredstev za gnojenje sestavine v enakih količinah ali če imajo posamezna sredstva za gnojenje EU, uporabljena za mešanico, enake formulacije1, standard za uporabo izbere uporabnik.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2025
Nadomešča:
SIST-TS CEN/TS 17703:2023
Rastlinski biostimulanti - Določanje kroma Cr(VI)
Plant biostimulants - Determination of chromium(VI)
Pflanzen-Biostimulanzien - Bestimmung von Chrom(VI)
Biostimulants des végétaux - Dosage du chrome(VI)
Ta slovenski standard je istoveten z: EN 17703:2024
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 17703
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2024
EUROPÄISCHE NORM
ICS 65.080 Supersedes CEN/TS 17703:2022
English Version
Plant biostimulants - Determination of chromium(VI)
Biostimulants des végétaux - Dosage du chrome(VI) Pflanzen-Biostimulanzien - Bestimmung von
Chrom(VI)
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 17703:2024 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
Introduction . 3
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Principle . 7
5 Chemicals . 7
6 Apparatus and materials . 8
7 Procedure . 9
7.1 Sampling and preparation of samples. 9
7.2 Preparation of analytical solution . 9
7.3 Chromatographic conditions . 9
7.4 Calibration . 9
7.5 Determination of the recovery rate . 10
8 Calculation and expression of results . 11
8.1 Calculation of chromium(VI) content . 11
8.2 Recovery rate (according to 7.5) . 11
8.3 Expression of results . 12
9 Test report . 12
Annex A (informative) Results of the inter-laboratory study . 13
A.1 Inter-laboratory tests . 13
A.2 Statistical results for the determination of Cr(VI) . 13
Annex B (informative) Chromatographic conditions for direct detection method . 15
B.1 General. 15
B.2 Example of ion chromatographic conditions . 15
B.2.1 Mobile phase reagents . 15
B.2.2 Instrumental conditions . 15
Annex C (informative) Chromatographic conditions for method with post-column reaction
................................................................................................................................................................... 17
C.1 General. 17
C.2 Chromatographic system and apparatus required . 17
C.3 Example of analytical conditions . 18
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 . 21
Bibliography . 22
European foreword
This document (EN 17703:2024) 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 17703:2022.
In comparison with the previous edition no significant technical changes were applied in this document.
The following main editorial changes have been made:
— In the Introduction, standards used as basis for the document and the description of Annexes A, B
and C were added;
— In the Scope (Clause 1), the applicability of the document to blends was added;
— The Normative references (Clause 2) and the Bibliography were reordered. Clause 2 only contains
the references that some or all of their content constitute requirements of this document, while the
other references were included in the Bibliography;
— The principle (Clause 4) was better clarified;
— In Clause 8, the calculation and the expression of the results were aligned to EN 17704:2024 for the
dry matter expression;
— In the test report (Clause 9) further information was added;
— Annex A on the results of the inter-laboratory study was added and consequently Annex A
(Chromatographic conditions for direct detection method) and Annex B (Chromatographic
conditions for method with post-column reaction) became Annex B and C respectively;
— In Annex B and Annex C, two examples of chromatograms were added;
— Annex ZA for the relationship with EU Legislation was added;
— In the text, if references were superseded, the latest edition has been mentioned.
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 provides the method for the chromium VI extraction and determination as mentioned in
Annex I, Part II, PFC 6, item 2(b) of Regulation (EU) 2019/1009 [1].
Standards for determination of chromium VI in soil and waste [2] and for leather [3] were studied and
considered as a basis of this document.
This document contains two annexes (B and C) which describe two possible ways for determining
chromium VI by ion chromatography. Annex B describes an example of chromatographic conditions for
the direct detection method, while Annex C explains the chromatographic conditions for method with
post-column reaction. Both methods can be applied to determine Chromium VI. The choice depends on
the equipment available in laboratories.
The inter-laboratory study reflects the final statistical characteristics of the method for the determination
of chromium VI content in plant biostimulants. The results are given in Annex A (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 verifying that hexavalent chromium (Cr(VI)) is not present in plant
biostimulants.
This document is applicable to all types of plant biostimulants (solid and liquid) used in agriculture.
The method specified is suitable to quantify the chromium(VI) content in plant biostimulants down to
2 mg/kg.
The results obtained from this method are strictly dependent on the extraction conditions. Results
obtained by using other extraction procedures (extraction solution, pH, extraction time, etc.) are not
comparable with the results produced by the procedure specified in this document.
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: 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 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
EN 17704:2024, Plant biostimulants — Determination of dry matter
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
An example of such a blend is a product with 2 claimed functions consisting of a non-microbial plant biostimulant
and an organic fertilizer composed of 1 kg/kg of plant biostimulant from seaweed.
3.1
chromium(VI) content
amount of chromium(VI) in plant biostimulant determined after extraction with an aqueous salt solution
at pH 7,0 to 8,0
Note 1 to entry: The chromium(VI) content is reported as chromium(VI) in milligrams per kilogram (mg/kg),
expressed as the dry mass of the sample.
[SOURCE: EN ISO 17075-2:2017, 3.1 [3], modified — “leather” was replaced by “plant biostimulants”]
4 Principle
To prove the compliance with the limit value for chromium(VI) in plant biostimulants, there is the
possibility to choose between:
— Using a testing method determining the total chromium content, as long as the result of the test
shows a content below the limit value for chromium(VI). In such a case, it can be safely assumed that
the plant biostimulant complies with the limit value for chromium (VI); or
— Using a testing method which determines only chromium(VI) content.
The determination of the total chromium in plant biostimulants can be performed by aqua regia digestion
(EN 17701-1:2024, [4]) and ICP-AES determination (EN 17701-2:2024, [5]).
This standard specifies the procedure to determine directly the content of chromium (VI) in plant
biostimulants: extractable chromium(VI) is leached from the sample in phosphate buffer at pH 7,0 to 8,0.
An aliquot of the filtered extract is analysed for Cr(VI) using ion-exchange chromatography with UV-VIS
detection.
5 Chemicals
All reagents used shall have at least analytical grade purity.
5.1 Extraction solution
Dissolve 22,8 g of dipotassium hydrogenphosphate trihydrate (K HPO ·3H O) in 1 000 ml water (5.7),
2 4 2
adjusted to pH 8,0 ± 0,1 with phosphoric acid solution (5.2). Degas this solution with either argon or
nitrogen (5.6) or ultrasonic bath.
Standard practice is to make up a fresh solution each day. However, the solution can be kept for up to one
week in a refrigerator at (4 ± 3) °C but shall be warmed to room temperature and degassed prior to use.
5.2 Phosphoric acid solution
700 ml o-phosphoric acid, ρ = 1,71 g/ml, made up to 1 000 ml with water (5.7).
First add approximately 200 ml of water (5.7) to a 1 000 ml volumetric flask, then add the 700 ml of o-
phosphoric acid and dilute to the mark with water (5.7).
5.3 Potassium dichromate (K Cr O ), dried for (16 ± 2) h at (105 ± 5) °C.
2 2 7
5.4 Chromium(VI) stock solution
Dissolve 2,829 g potassium dichromate (K Cr O ) (5.3) in water (5.7) in a volumetric flask and make up
2 2 7
to 1 000 ml with water (5.7). One ml of this solution contains 1 mg of chromium.
The solution can be kept for up to 12 months in a refrigerator at (4 ± 3) °C but shall be warmed to room
temperature prior to use.
It is also possible to use a commercial standard solution with a certified Cr(VI) concentration that can be
connected to national standards. Observe the expiry date or recommended shelf life stated by the
manufacturer.
5.5 Chromium(VI) standard solution
Pipette 1 ml of solution (5.4) into a 1 000 ml volumetric flask and make up to the mark with extraction
solution (5.1). One ml of this solution contains 1 μg of chromium.
The solution can be kept for up to one week in a refrigerator at (4 ± 3) °C but shall be warmed to room
temperature prior to use.
A stock solution of hexavalent chromium at this concentration level is an alternative available
commercially.
5.6 Argon or nitrogen, oxygen-free
Preference should be given to argon as an inert gas instead of nitrogen because argon has a higher specific
mass than air.
5.7 Distilled or deionised water, with a specific conductivity not higher than 0,2 mS/m at 25 °C.
5.8 Magnesium chloride hexahydrate (MgCl⋅6H O)
2 2
Dissolve 85,4 g of magnesium chloride hexahydrate (MgCl⋅6H O) in a 100 ml volumetric flask, dilute
2 2
with water (5.7), close and mix thoroughly.
6 Apparatus and materials
Usual laboratory equipment and, in particular, the following.
−1
6.1 Suitable mechanical orbital shaker, (100 ± 10) min .
6.2 Conical flask, of capacity 250 ml, with stopper.
6.3 Aeration tube and flow meter, suitable for a flow rate of (50 ± 10) ml/min.
6.4 pH meter, with glass electrode.
6.5 Membrane filter, 0,45 μm pore size [polytetrafluoroethylene (PTFE) or polyamide 66].
6.6 Common laboratory glassware and pipettes.
6.7 Vacuum device, suitable for filtration of extraction solution, mobile phase, and sample extracts.
6.8 Ion-exchange chromatograph, with UV or visible detector or high performance liquid
chromatography (HPLC) with anion-exchange column and UV or visible detector. A photo diode
array detector (DAD) is recommended.
6.9 Analytical balance, capable of weighing to 0,1 mg.
6.10 Syringe membrane filters, of polyamide 6.6 of 0,45 μm for filtration of standards.
6.11 Suitable vials for Ionic Chromatography (IC) or HPLC.
7 Procedure
7.1 Sampling and preparation of samples
For sampling, EN 17702-1:2024 shall be used. If sampling in accordance with EN 17702-1:2024 is not
possible, details about the sampling shall be given in the test report.
For the preparation of the samples, EN 17702-2:2024 shall be used. For products that can decompose or
react when heated, grinding shall be carried out in order to prevent heating.
7.2 Preparation of analytical solution
Weigh (6.9) approximately (2 ± 0,1) g of sample of plant biostimulant to the nearest 0,001 g. Pipette
100 ml of degassed solution (5.1) into a 250 ml conical flask (6.2). Displace oxygen by passing oxygen-
free argon (or nitrogen) (5.6) into the flask for 5 min with a volume flow of (50 ± 10) ml/min. Remove
the aeration tube (6.3), add the sample of plant biostimulant and close the flask with a stopper. Record
the extract volume as V and the weight of the sample as m.
Shake the conical flask with the sample of plant biostimulant for (30,0 ± 0,5) min on a mechanical orbital
−1
shaker at (100 ± 10) min (6.1) at room temperature to extract the chromium(VI).
Shake the suspension in a smooth circular movement to keep the sample of plant biostimulant from
adhering to the wall of the flask and avoid shaking faster than specified.
Immediately after completing the 30-min extraction, filter the contents of the conical flask through a
membrane fi
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