FprEN 17703

SLOVENSKI STANDARD
oSIST prEN 17703:2023
01-maj-2023
Rastlinski biostimulanti - Določevanje 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: prEN 17703
ICS:
65.080 Gnojila Fertilizers
oSIST prEN 17703:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 17703:2023
oSIST prEN 17703:2023
DRAFT
EUROPEAN STANDARD
prEN 17703
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2023
ICS 65.080 Will supersede 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 draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 455.
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
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17703:2023 E
worldwide for CEN national Members.

oSIST prEN 17703:2023
prEN 17703:2023 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 6
5 Chemicals . 6
6 Apparatus and materials . 7
7 Procedure . 8
7.1 Sampling and preparation of samples. 8
7.2 Preparation of analytical solution . 8
7.3 Chromatographic conditions . 8
7.4 Calibration . 8
7.5 Determination of the recovery rate . 9
8 Calculation and expression of results . 10
8.1 Calculation of chromium(VI) content . 10
8.2 Recovery rate (according to 7.5) . 10
8.3 Expression of results . 11
9 Test report . 11
Annex A (informative) Results of the inter-laboratory study . 12
A.1 Inter-laboratory tests . 12
A.2 Statistical results for the determination of Cr(VI) . 12
Annex B (informative) Chromatographic conditions for direct detection method . 14
B.1 General. 14
B.2 Example of ion chromatographic conditions . 14
B.2.1 Mobile phase reagents . 14
B.2.2 Instrumental conditions . 14
Annex C (informative)  Chromatographic conditions for method with post-column reaction
................................................................................................................................................................... 16
C.1 General. 16
C.2 Chromatographic system and apparatus required . 16
C.3 Example of analytical conditions . 17
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 . 19
Bibliography . 20
oSIST prEN 17703:2023
prEN 17703:2023 (E)
European foreword
This document (prEN 17703:2023) has been prepared by Technical Committee CEN/TC 455 “Plant
Biostimulants”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede CEN/TS 17703:2022.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s) / Regulation(s).
For relationship with EU Directive(s) / Regulation(s), see informative Annex ZA, which is an integral part
of this document.
oSIST prEN 17703:2023
prEN 17703:2023 (E)
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 and M/564 Amd1, also contributes to the
Communication on “Innovating for Sustainable Growth: A Bio economy for Europe”. Working Group 4
“Other safety parameters”, was created to develop a work programme as part of this request. Technical
committee CEN/TC 455 “Plant Biostimulants” was established to carry out the work programme 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 boosting the confidence of farmers, industry, and consumers in biostimulants, and will
promote and support commercialisation of the European biostimulant industry.
oSIST prEN 17703:2023
prEN 17703:2023 (E)
1 Scope
This document was developed to provide a method for verifying that hexavalent chromium (CrVI) is not
present in plant biostimulants in a concentration that exceeds the respective limits outlined in the EU
Regulation on Fertilising Products [1].
This document is applicable to all types of plant biostimulants (solid and liquid ) used in agriculture.
The method described 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 described in this document. Therefore, this
document is highly recommended to quantify the chromium(VI) content in blends of fertilizing products
containing plant biostimulants, independently of the percentage of the different parts forming the blend.
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:— , Plant biostimulants — Sampling and sample preparation — Part 1: Sampling
EN 17702-2:— , Plant biostimulants — Sampling and sample preparation — Part 2: Sample preparation
EN 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
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, definition 3.1]

According to the definition of “solid form” and “liquid form” to the current EU legislation when it is published.
Under preparation
Under preparation
Under preparation
oSIST prEN 17703:2023
prEN 17703:2023 (E)
4 Principle
To prove the compliance with the limit value defined in Regulation (EU) 2019/1009 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).
— Using a testing method which determines only chromium(VI) content.
The determination of the total chromium in plant biostimulants can be performed using the following
references:
EN 17701-1:— , Plant biostimulants — Determination of specific elements — Part 1: Digestion by aqua
regia for subsequent determination of elements
EN 17701-2:— , Plant biostimulants — Determination of specific elements — Part 2: Determination of
total content of Cd, Pb, Ni, As, Cr, Cu and Zn
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 (K HPO ·3H O) in 1 000 ml water (5.7), adjusted to
2 4 2
pH 8,0 ± 0,1 with phosphoric acid (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 deionised 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 deionised water.
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
...