oSIST prEN 17778:2026

SLOVENSKI STANDARD
01-marec-2026
Organska in organsko-mineralna gnojila - Določanje kroma Cr(VI)
Organic and organo-mineral fertilizers - Determination of chromium(VI) content
Organische und organisch-mineralische Düngemittel - Bestimmung des Gehalts an
Chrom(VI)
Engrais organiques et organo-minéraux - Détermination de la teneur en chrome(VI)
Ta slovenski standard je istoveten z: prEN 17778
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2026
ICS 65.080 Will supersede CEN/TS 17778:2022
English Version
Organic and organo-mineral fertilizers - Determination of
chromium(VI) content
Engrais organiques et organo-minéraux - Organische und organisch-mineralische Düngemittel -
Détermination de la teneur en chrome(VI) Bestimmung des Gehalts an Chrom(VI)
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 17778:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Principle . 7
5 Reagents . 7
6 Apparatus . 8
7 Procedure . 9
7.1 Sampling and sample preparation . 9
7.2 Preparation of analytical solution . 9
7.2.1 Solid samples . 9
7.2.2 Liquid samples . 10
7.3 Chromatographic conditions . 10
7.4 Calibration. 10
7.5 Determination of the recovery rate . 11
8 Calculation and expression of results . 12
8.1 Calculation of chromium(VI) content . 12
8.2 Recovery rate (according to 7.5) . 13
8.3 Expression of results . 13
9 Precision . 13
9.1 Inter-laboratory study . 13
9.2 Repeatability . 13
9.3 Reproducibility . 13
10 Test report . 14
Annex A (informative) Results of the inter-laboratory study . 15
A.1 Inter-laboratory tests . 15
Annex B (informative) Chromatographic conditions for direct detection method . 17
B.1 General . 17
B.2 Example of ion chromatographic conditions . 17
B.2.1 Mobile phase reagents . 17
B.2.2 Instrumental conditions . 17
Annex C (informative) Chromatographic conditions for method with post-column reaction
............................................................................................................................................................... 19
C.1 General . 19
C.2 Chromatographic system and apparatus required . 19
C.3 Example of analytical conditions . 20
C.3.1 Mobile phase and post-column reagents . 20
C.3.2 Preparation of the mobile phase . 20
C.3.3 Preparation of post-column reagent . 20
C.3.4 Instrumental conditions . 21
C.4 Examples of chromatograms . 21
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 . 23
Bibliography . 24

European foreword
This document (prEN 17778:2026) 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 the CEN Enquiry.
This document will supersede CEN/TS 17778:2022.
Compared to the previous edition, prEN 17778:2026 includes the following significant technical
changes:
— the CEN Technical Specification has been adopted as a European Standard including the
addition of Annex ZA;
— Introduction modified to add standards used as basis for the document and the description of
Annexes A, B and C;
— Scope (Clause 1) updated including clarifications on fertilizing product blends;
— Normative references (Clause 2) and Bibliography updated;
— Principle (Clause 4) updated;
— 7.2.1 modified to reduce the time for extraction;
— Clause 8, aligned to prEN 17773:2026 regarding the calculation and the expression of the
results for the dry matter;
— Test report (Clause 9) modified with addition of further information;
— Annex A (Results of the interlaboratory study) added;
— Annex B and Annex C modified with substitution of chromatograms.
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.
Introduction
Regulation (EU) 2019/1009 [2] lays down the rules on the making available on the market of EU
fertilizing products and the specific safety and quality requirements for the defined product
function categories (PFCs). Organic and organo-mineral fertilizers have been classified as
PFC 1(A) and PFC 1(B).
This document provides the method for the determination of the chromium(VI) extraction and
determination as mentioned in Annex I, Part II, PFC 1(A) and PFC 1(B) of Regulation (EU)
2019/1009 [2] in order to measure the compliance with the related requirement in that
Regulation.
Standards for determination of chromium(VI) in soil and waste [3], fertilizers [4] and for leather
[1] 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 organic and organo-mineral fertilizers. 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 the determination of hexavalent chromium (chromium(VI))
in organic and organo-mineral fertilizers.
The method specified is suitable to quantify the chromium(VI) content in organic and organo-
mineral fertilizers down to 2 mg/kg dry matter.
The results obtained from this method are strictly dependent on the extraction conditions. Results
obtained by using other extraction procedures (extraction solution, pH of the extraction solution,
extraction time, extraction temperature, etc.) are not comparable with the results produced by
the procedure described in this document.
This document is applicable to fertilizing products blends where a blend is a mix of at least two of
the following components: fertilizers, liming materials, soil improvers, growing media, inhibitors,
plant biostimulants and where organic matter is present in at least one of the products in the
blend. In case a fertilizing product blend is composed only of inorganic products, the European
Standard for inorganic fertilizers or liming materials applies. 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.
prEN 17773:2026, Organic and organo-mineral fertilizers — Determination of the dry matter
content
prEN 12944-1:2026, Fertilizers, liming materials and inhibitors — Vocabulary — Part 1: General
terms
prEN 12944-2:2026, Fertilizers, liming materials and inhibitors — Vocabulary — Part 2: Terms
relating to fertilizers
EN 1482-2:2024, Fertilizers, liming materials and inhibitors — Sampling and sample preparation
— Part 2: general sample preparation provisions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in prEN 12944-1:2026 and
prEN 12944-2:2026 and the following apply.
ISO and IEC maintain terminological 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
chromium(VI) content
Cr(VI)
amount of chromium(VI) in organic and organo-mineral fertilizers determined after extraction
with an aqueous salt solution at pH 7,0 to pH 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 [1], 3.1, modified: “leather” is replaced by “organic and organo-
mineral fertilizers”]
4 Principle
To prove the compliance with the limit value for chromium(VI) in organic and organo-mineral
fertilizers, 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 organic fertilizer or the organo-mineral fertilizer 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 organic and organo-mineral fertilizers can be
performed by aqua regia digestion (prEN 17768 [5]) and ICP-AES determination (prEN 17770
[6]).
This standard specifies the procedure to directly determine the content of chromium(VI) in
organic and organo-mineral fertilizers: extractable chromium(VI) is leached from the sample in
phosphate buffer at pH 7,0 to pH 8,0. An aliquot of the filtered extract is analysed for
chromium(VI) using ion-exchange chromatography with UV-VIS detection.
5 Reagents
All reagents used shall have at least analytical grade.
5.1 Extraction solution
Dissolve 22,8 g dipotassium hydrogen phosphate trihydrate (K HPO ·3H O) in 1 000 ml water
2 4 2
(5.7), adjusted to pH 8,0 ± pH 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, density 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 ± 2) °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
2 2 7
make up to 1 000 ml with water (5.7). 1 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). 1 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, free from the elements to be determined.
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,
2 2
dilute with water (5.7), close and mix thoroughly.
6 Apparatus
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 6.6].
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/VIS detector or high-performance liquid
chromatography (HPLC) with anion-exchange column and UV/VIS 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 pore size, for filtration of standards.
6.11 Suitable vials for ion chromatography or HPLC.
7 Procedure
7.1 Sampling and sample preparation
Sampling is not part of the method specified in this document. Recommended sampling methods
are given in EN 1482-1 [7] and in EN 1482-3 [8].
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 transport or storage.
Sample preparation shall be carried out in accordance with EN 1482-2:2024.
For products that can decompose or react when heated, grinding shall be carried out in order to
prevent heating.
Details about the sampling and sample preparation shall be given in the test report.
7.2 Preparation of analytical solution
7.2.1 Solid samples
The operator shall weigh approximately (2 ± 0,1) g of sample of organic or organo-mineral
fertilizer to the nearest 0,001 g with an analytical balance (6.9).
Following tasks shall be performed:
— Pipette 100 ml (V ) 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 and close the flask
with a stopper. Record the extract volume as V and the mass of the sample as m.
— Shake the conical flask with the sample for (30,0 ± 0,5) min on a mechanical orbital shaker at
−1
(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 from adhering to
the wall of the flask and avoid shaking faster than specified.
— Immediately after completing the 30 min of extraction, filter the contents of the conical flask
through a membrane filter into a glass or plastic vessel with lid. Check the pH of the solution.
The pH of the solution shall be between 7,0 and 8,0. If the pH of the solution is not within this
range, start the complete procedure again. Consider using a smaller sample mass, if the pH is
not between 7,0 and 8,0. In this case, the quantification limit will be increased.
— Transfer an aliquot of the filtered extract into a vial (6.11). Instrumental determination of
chromium(VI) should be performed as soon as possible and no later than 60 min after the
extraction phase to avoid risks of reduction.
— If the sample is expected to contain a significant amount of chromium(III), 1 ml of magnesium
chloride solution (5.8) can be added before displacing oxygen into the 250 ml volumetric flask
(6.2) containing the 100 ml of the extraction solution (5.1).
7.2.2 Liquid samples
The operator shall weigh approximately (10 ± 0,1) g of sample of organic or organo-mineral
fertilizer to the nearest 0,001 g with an analytical balance (6.9).
The following tasks shall be performed:
— Pipette 100 ml (V ) 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 and close the flask with a
stopper. Record the extract volume as V (100 ml + sample volume in ml).
— Shake the conical flask with the sample for (10 ± 0,5) min on a mechanical orbital shaker at
−1
(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 from adhering to the
wall of the flask and avoid shaking faster than specified.
— Immediately after completing the 10 min of extraction, filter the contents of the conical flask
through a membrane filter into a glass or plastic vessel with lid. Check
...