SIST-TS CEN/TS 17778:2023

Organic and organo-mineral fertilizers - Determination of the chromium (VI) content by chromotography

The document establishes the methodology for the determination of the chromium VI content in organic and organo-mineral fertilizers by ion chromatography.

Organische und organisch-mineralische Düngemittel - Bestimmung des Gehalts an Chrom(VI) mittels Chromatographie

Dieses Dokument gilt für Düngeprodukte, die den Kategorien PFC 1(A) und PFC 1(B) zDieses Dokument ist für Düngeprodukte anzuwenden, die den Kategorien PFC 1(A) und PFC 1(B) zugeordnet oder als Komponente der Kategorien PFC 1(A) und PFC 1(B) in PFC 7 der Verordnung (EU) 2019/1009 [3] eingestuft sind. Das vorliegende Verfahren wurde jedoch nicht für Mischungen validiert.
Dieses Dokument legt ein Verfahren zur Bestimmung von sechswertigem Chrom (Chrom(VI)) in organischen und organisch-mineralischen Düngemitteln fest.
Das beschriebene Verfahren ist geeignet, um den Chrom(VI) Gehalt in organischen und organisch-mineralischen Düngemitteln bis zu 2 mg/kg Trockenmasse zu quantifizieren.
Die mit dem Verfahren erzielten Ergebnisse sind streng von den Extraktionsbedingungen abhängig. Ergebnisse, die mit anderen Extraktionsverfahren (Extraktionslösung, pH Wert der Extraktions¬lösung, Extraktionszeit, Extraktionstemperatur usw.) erzielt wurden, sind nicht mit den Ergebnissen vergleichbar, die mit dem in diesem Dokument beschriebenen Verfahren erzielt wurden.
ugeordnet oder als Komponente der Kategorien PFC 1(A) und PFC 1(B) in PFC 7 der Verordnung (EU) 2019/1009 [3] eingestuft sind. Das vorliegende Verfahren wurde jedoch nicht für Mischungen validiert.
Dieses Dokument legt ein Verfahren zur Bestimmung von sechswertigem Chrom (Chrom(VI)) in organischen und organisch-mineralischen Düngemitteln fest.
Das beschriebene Verfahren ist geeignet, den Chrom(VI)-Gehalt in organisch-mineralischen Düngemitteln bis zu 2 mg/kg Trockenmasse zu quantifizieren.
Die mit dem beschriebenen Verfahren erzielten Ergebnisse sind streng von den Extraktionsbedingungen abhängig. Ergebnisse, die mit anderen Extraktionsverfahren (Extraktionslösung, pH-Wert der Extraktions-lösung, Extraktionsdauer, Extraktionstemperatur usw.) erzielt wurden, sind nicht mit

Engrais organiques et organo-minéraux - Détermination de la teneur en chrome(VI)

Le présent document est applicable aux fertilisants qui sont classés dans les catégories PFC 1(A) et PFC 1(B) ou comme composants de PFC 1(A) et de PFC 1(B) dans la catégorie PFC 7 du Règlement (UE) 2019/1009 [3]. Toutefois, la présente méthode n’a pas été validée pour les mélanges.
Le présent document spécifie une méthode pour la détermination du chrome hexavalent [chrome(VI)] dans les engrais organiques et organo-minéraux.
La méthode décrite est adaptée à la quantification, dans les engrais organiques et organo-minéraux, de la teneur en chrome(VI) jusqu’à une limite de quantification de 2 mg/kg de matière sèche.
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 de la solution d’extraction, durée d’extraction, température d’extraction, etc.) ne sont pas comparables aux résultats acquis avec le mode opératoire décrit dans le présent document.

Organska in organsko-mineralna gnojila - Določevanje kroma Cr(VI) s kromatografijo

Dokument vzpostavlja metodologijo za določevanje kroma VI v organskih in organsko-mineralnih gnojilih z ionsko kromatografijo.

General Information

• Status: Published
• Public Enquiry End Date: 02-Jan-2022
• Publication Date: 09-Jan-2023
• ICS: 65.080 - Fertilizers
• Technical Committee: KAT - Soil quality
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 06-Jan-2023
• Due Date: 13-Mar-2023
• Completion Date: 10-Jan-2023
• Directive: 2019/1009 - Regulation (EU) 2019/1009 of the European Parliament and of the Council of 5 June 2019 laying down rules on the making available on the market of EU fertilising products and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003
• Mandate: M/564 - Fertilising products in support of Regulation (EU) 2019/1009
• Ref Project: CEN/TS 17778:2022 - Organic and organo-mineral fertilizers - Determination of the chromium (VI) content by chromotography

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS CEN/TS 17778:2023
01-februar-2023
Organska in organsko-mineralna gnojila - Določevanje kroma Cr(VI) s
kromatografijo
Organic and organo-mineral fertilizers - Determination of the chromium (VI) content by
chromotography
Organische und organisch-mineralische Düngemittel - Bestimmung des Gehalts an
Chrom(VI) mittels Chromatographie
Engrais organiques et organo-minéraux - Détermination de la teneur en chrome(VI)
Ta slovenski standard je istoveten z: CEN/TS 17778:2022
ICS:
65.080 Gnojila Fertilizers
SIST-TS CEN/TS 17778:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 17778:2023

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SIST-TS CEN/TS 17778:2023


CEN/TS 17778
TECHNICAL SPECIFICATION

SPÉCIFICATION TECHNIQUE

April 2022
TECHNISCHE SPEZIFIKATION
ICS 65.080
English Version

Organic and organo-mineral fertilizers - Determination of
the chromium (VI) content by chromotography
Engrais organiques et organo-minéraux - Organische und organisch-mineralische Düngemittel -
Détermination de la teneur en chrome(VI) Bestimmung des Gehalts an Chrom (VI)
This Technical Specification (CEN/TS) was approved by CEN on 13 March 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 17778:2022 E
worldwide for CEN national Members.

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CEN/TS 17778:2022 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Reagents . 6
6 Apparatus . 6
7 Procedure . 7
7.1 Sampling and sample preparation . 7
7.2 Preparation of analytical solution . 7
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) Chromatographic conditions for direct detection method . 12
Annex B (informative) Chromatographic conditions for method with post-column reaction
. 15
Bibliography . 19

2

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European foreword
This document (CEN/TS 17778:2022) has been prepared by Technical Committee CEN/TC 260
“Fertilizers and liming materials”, the secretariat of which is held by DIN.
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 standardisation 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.
3

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CEN/TS 17778:2022 (E)
Introduction
Regulation (EU) 2019/1009 [3] 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 defines test methods for the determination of the chromium (VI) content to be
used for organic and organo-mineral fertilizers in order to measure the compliance with the
related requirement in the Regulation (EU) 2019/1009 [3].
4

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CEN/TS 17778:2022 (E)
1 Scope
This document is applicable to fertilizing products, which are classified as PFC 1(A) and PFC 1(B)
or the PFC 1(A) and PFC 1(B) component in PFC 7 of Regulation (EU) 2019/1009 [3]. However,
the present method was not validated on blends.
This document specifies a method for the determination of hexavalent chromium (chromium (VI))
in organic and organo-mineral fertilizers.
The method described 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.
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 ISO 3696:1995, Water for analytical laboratory use — Specification and test methods (ISO
3696:1987)
CEN/TS 17773:2022, Organic and organo-mineral fertilizers — Determination of the dry matter
content
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
Chromium (VI) content
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, 3.1, modified: “leather” is replaced by “organic and organo-
mineral fertilizers” and “pH 7,0 to 8,0” is replaced by “pH 7,0 to pH 8,0”]
4 Principle
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

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5 Reagents
All reagents used shall have at least analytical grade.
5.1 Extraction solution
Dissolve 22,8 g dipotassium hydrogen phosphate K HPO ·3H O in 1 000 ml water (5.7), adjusted
2 4 2
to pH 8,0 ± pH 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 may 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 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 ± 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.
A stock solution at this concentration level of hexavalent chromium is an alternative available
commercially.
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 may 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, Grade 3 quality as specified in EN ISO 3696:1995.
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

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CEN/TS 17778:2022 (E)
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 detector or high-performance liquid
chromatography (HPLC) with anion-exchange column and UV 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 nylon, 0,45 μm pore size, for filtration of standards.
6.11 Suitable vials for HPLC.
7 Procedure
7.1 Sampling and sample preparation
Sampling and sample preparation should be performed carefully, following the principles
described in EN 1482 (all parts) with appropriate adaptations, required to account for
specificities of organic and organo-mineral fertilizers.
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 (6.9) approximately (2 ± 0,1) g of sample of organic or organo-mineral
fertilizer to the nearest 0,001 g.
Following tasks shall be performed:
• Pipette 100 ml (V ) of degassed solution (5.1) into a 250 ml conical flask (6.2). Displace
0
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.
• Shake the conical flask with the sample for (180 ± 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 3 h 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.
• 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.
7

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7.2.2 Liquid samples
The operator shall weigh (6.9) approximately (10 ± 0,1) g of sample of organic or organo-mineral
fertilizer to the nearest 0,001 g.
The following tasks shall be performed:
• 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 and close the flask with a
stopper. Record the ex
...

SLOVENSKI STANDARD
kSIST-TS FprCEN/TS 17778:2021
01-december-2021
Organska in organsko-mineralna gnojila - Določevanje kroma Cr (VI)
Organic and organo-mineral fertilizers - Determination of the 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: FprCEN/TS 17778
ICS:
65.080 Gnojila Fertilizers
kSIST-TS FprCEN/TS 17778:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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kSIST-TS FprCEN/TS 17778:2021


FINAL DRAFT
TECHNICAL SPECIFICATION
FprCEN/TS 17778
SPÉCIFICATION TECHNIQUE

TECHNISCHE SPEZIFIKATION

November 2021
ICS 65.080
English Version

Organic and organo-mineral fertilizers - Determination of
the 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 Technical Specification is submitted to CEN members for Vote. It has been drawn up by the Technical Committee
CEN/TC 260.

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.

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 Technical Specification. It is distributed for review and comments. It is subject to change
without notice and shall not be referred to as a Technical Specification.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TS 17778:2021 E
worldwide for CEN national Members.

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kSIST-TS FprCEN/TS 17778:2021
FprCEN/TS 17778:2021 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 6
5 Reagents . 6
6 Apparatus . 7
7 Procedure . 7
7.1 Sampling and sample preparation . 7
7.2 Preparation of analytical solution . 7
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) .11
8.3 Expression of results .11
9 Test report .11
Annex A (informative) Chromatographic conditions for direct detection method .12
Annex B (informative) Chromatographic conditions for method with post-column
reaction .15
Bibliography .19

2

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FprCEN/TS 17778:2021 (E)

European foreword
This document (FprCEN/TS 17778:2021) 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 Vote on TS.
This document has been prepared under a standardisation request given to CEN by the European
Commission and the European Free Trade Association.
3

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kSIST-TS FprCEN/TS 17778:2021
FprCEN/TS 17778:2021 (E)
Introduction
Regulation (EU) 2019/1009 [3] 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 defines test methods for the determination of the chromium (VI) content to be
used for organic and organo-mineral fertilizers in order to measure the compliance with the
related requirement in the Regulation (EU) 2019/1009 [3].
4

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kSIST-TS FprCEN/TS 17778:2021
FprCEN/TS 17778:2021 (E)

1 Scope
This document is applicable to fertilizing products, which are classified as PFC 1(A) and PFC 1(B)
or the PFC 1(A) and PFC 1(B) component in PFC 7 of Regulation (EU) 2019/1009 [3]. However,
the present method was not validated on blends.
This document specifies a method for the determination of hexavalent chromium (chromium (VI))
in organic and organo-mineral fertilizers.
The method described is suitable to quantify the chromium (VI) content in 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.
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 ISO 3696:1995, Water for analytical laboratory use - Specification and test methods (ISO
3696:1987)
FprCEN/TS 17773:2021, Organic and organo-mineral fertilizers – Determination of the dry matter
content
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
Chromium (VI) content
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, 3.1, modified: “leather” is replaced by “organic and organo-
mineral fertilizers” and “pH 7,0 to 8,0” is replaced by “pH 7,0 to pH 8,0”]
5

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FprCEN/TS 17778:2021 (E)
4 Principle
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 K HPO ·3H O in 1 000 ml water (5.7), adjusted
2 4 2
to pH 8,0 ± pH 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 may 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 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 ± 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.
A stock solution at this concentration level of hexavalent chromium is an alternative available
commercially.
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 may 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,
Grade 3 quality as specified in EN ISO 3696:1995.
6

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FprCEN/TS 17778:2021 (E)

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 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 detector or high-performance liquid
chromatography (HPLC) with anion-exchange column and UV 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 nylon, 0,45 μm pore size, for filtration of standards.
6.11 Suitable vials for HPLC.
7 Procedure
7.1 Sampling and sample preparation
Sampling and sample preparation should be performed carefully, following the principles
described in EN 1482 (all parts) with appropriate adaptations, required to account for
specificities of organic and organo-mineral fertilizers.
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 (6.9) approximately (2 ± 0,1) g of sample of organic or organo-mineral
fertilizer to the nearest 0,001 g.
Following tasks shall be performed:
• Pipette 100 ml (V ) of degassed solution (5.1) into a 250 ml conical flask (6.2). Displace
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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.
• Shake the conical flask with the sample for (180 ± 5) min on a mechanical orbital shaker at
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(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 3 h 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.
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kSIST-TS FprCEN/TS 17778:2021
FprCEN/TS 17778:2021 (E)
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.
• 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.
7.2.2 Liquid samples
The operator shall weigh (6.9) approximately (10 ± 0,1) g of sample of organic or organo-mineral
fertilizer to the nearest 0,001 g.
The following tasks shall be performed:
• 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 and close the flask with a
stopper. Record the extract volume as V (100 ml + sample volume in ml).
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• Shake the conical flask with the sample for (10 ± 1) min on a mechanical orbital 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 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 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
...