Organo-mineral fertilizers - Determination of the chelated micronutrient content and the chelated fraction of micronutrients by treatment with a cation exchange resin

This document specifies a method for the determination of the chelated micronutrient content and the chelated fraction of a micronutrient, in organo-mineral fertilizers, having an organic matrix based on vegetal residues (cocoa shells, grape residue, soybean residue, etc), algae extract, and animal meal (feather, bones, blood, etc) and containing UVCB, EDDHA, EDDHMA, HBED, EDDHSA micronutrients by the treatment with a cation exchange resin.
The limit of determination of the chelated micronutrient content highly depends on the specific electrical conductivity of the sample, on the amount of nutrient present, and varies between 0,005 % in simple matrices with high amounts of micronutrient, and 0,5 % in more complex cases (see 9.1).

Organisch-mineralische Düngemittel - Bestimmung des Gehalts an chelatisierten Spurennährstoffen und des chelatisierten Anteils an Spurennährstoffen durch Behandlung mit einem Kationenaustauscherharz

Dieses Dokument legt ein Verfahren zur Bestimmung des Gehalts an chelatisierten Spurennährstoffen und des Anteils eines chelatisierten Spurennährstoffs in organisch-mineralischen Düngemitteln durch Behandlung mit einem Kationenaustauschharz fest, wobei diese Düngemittel eine organische Matrix auf Basis von pflanzlichen Reststoffen (Kakaoschalen, Traubenreststoffe, Sojabohnenreststoffe, usw.), Algenextrakt und Tiermehl (Federn, Knochen, Blut, usw.) aufweisen und UVCB-, EDDHA-, EDDHMA-, HBED-, EDDHSA-Spurennährstoffe enthalten.
Die Bestimmungsgrenze des Gehalts an chelatisiertem Spurennährstoffen hängt stark von der spezifischen elektrischen Leitfähigkeit der Probe und der Menge des vorhandenen Nährstoffs ab und variiert zwischen 0,005 % in einfachen Matrices mit großen Mengen an Spurennährstoffen und 0,5 % in komplexeren Fällen (siehe 9.1).

Engrais organo-minéraux - Détermination de la teneur en oligo-éléments chélatés et de la fraction chélatée d'oligo-éléments par traitement avec une résine échangeuse de cations

Le présent document spécifie une méthode pour la détermination de la teneur en oligo-éléments chélatés et de la fraction chélatée d’un oligo-élément dans les engrais organo-minéraux ayant une matrice organique basée sur des résidus végétaux (coques de cacao, résidus de raisins, résidus de soja …), des extraits d’algue et des farines animales (plumes, os, sang ...) et contenant des oligo-éléments UVCB, EDDHA, EDDHMA, HBED, EDDHSA, par traitement avec une résine échangeuse de cations.
La limite de détermination de la teneur en oligo-éléments chélatés dépend en grande partie de la conductivité électrique spécifique de l’échantillon, de la quantité d’éléments nutritifs présents, et elle varie entre 0,005 % dans les matrices simples avec de grandes quantités d’oligo-éléments et 0,5 % dans les cas plus complexes (voir 9.1).

Organsko-mineralna gnojila - Določanje vsebnosti kelatiranih mikrohranil in deleža kelatiranih mikrohranil z obdelavo s kationsko izmenjalno smolo

General Information

Status
Published
Public Enquiry End Date
02-Jan-2022
Publication Date
09-Jan-2023
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
06-Jan-2023
Due Date
13-Mar-2023
Completion Date
10-Jan-2023

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SLOVENSKI STANDARD
SIST-TS CEN/TS 17790:2023
01-februar-2023

Organsko-mineralna gnojila - Določanje vsebnosti kelatiranih mikrohranil in deleža

kelatiranih mikrohranil z obdelavo s kationsko izmenjalno smolo

Organo-mineral fertilizers - Determination of the chelated micronutrient content and the

chelated fraction of micronutrients by treatment with a cation exchange resin
Organisch-mineralische Düngemittel - Bestimmung des Gehalts an chelatisierten
Spurennährstoffen und des chelatisierten Anteils an Spurennährstoffen durch
Behandlung mit einem Kationenaustauscherharz

Engrais organo-minéraux - Détermination de la teneur en oligo-éléments chélatés et de

la fraction chélatée d'oligo-éléments par traitement avec une résine échangeuse de

cations
Ta slovenski standard je istoveten z: CEN/TS 17790:2022
ICS:
65.080 Gnojila Fertilizers
SIST-TS CEN/TS 17790:2023 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST-TS CEN/TS 17790:2023
---------------------- Page: 2 ----------------------
SIST-TS CEN/TS 17790:2023
CEN/TS 17790
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
April 2022
TECHNISCHE SPEZIFIKATION
ICS 65.080
English Version
Organo-mineral fertilizers - Determination of the chelated
micronutrient content and the chelated fraction of
micronutrients by treatment with a cation exchange resin

Engrais organo-minéraux - Détermination de la teneur Organisch-mineralische Düngemittel - Bestimmung des

en oligo-éléments chélatés et de la fraction chélatée Gehalts an chelatisierten Spurennährstoffen und des

d'oligo-éléments par traitement avec une résine chelatisierten Anteils an Spurennährstoffen durch

échangeuse de cations Behandlung mit einem Kationenaustauscherharz

This Technical Specification (CEN/TS) was approved by CEN on 21 February 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 17790:2022 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST-TS CEN/TS 17790:2023
CEN/TS 17790:2022 (E)
Contents Page

European foreword ....................................................................................................................................... 3

Introduction ..................................................................................................................................................... 4

1 Scope ..................................................................................................................................................... 5

2 Normative references ..................................................................................................................... 5

3 Terms and definitions .................................................................................................................... 5

4 Principle .............................................................................................................................................. 6

5 Interferences ..................................................................................................................................... 6

6 Reagents .............................................................................................................................................. 6

7 Apparatus ............................................................................................................................................ 8

8 Sampling and sample preparation............................................................................................. 8

9 Procedure ........................................................................................................................................... 8

9.1 Extraction of the sample ................................................................................................................ 8

9.2 pH adjustment ................................................................................................................................... 9

9.3 Ion exchange separation ............................................................................................................... 9

9.4 Spectrometric determination .................................................................................................... 10

9.5 Water soluble micronutrient content determination ...................................................... 10

10 Expression of results ..................................................................................................................... 10

10.1 Chelated micronutrient content in the fertilizer ................................................................ 10

10.2 Chelated fraction of a micronutrient in the fertilizer ....................................................... 11

11 Test report ........................................................................................................................................ 11

Annex A (informative) Complete names of chelating agents ........................................................ 12

Bibliography ................................................................................................................................................... 13

---------------------- Page: 4 ----------------------
SIST-TS CEN/TS 17790:2023
CEN/TS 17790:2022 (E)
European foreword

This document (CEN/TS 17790:2022) 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 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.
---------------------- Page: 5 ----------------------
SIST-TS CEN/TS 17790:2023
CEN/TS 17790:2022 (E)
Introduction

Micronutrients are considered to be, in plant nutrition, a number of elements known to be needed in

small amounts for proper plant growth and development. The most common are Iron (Fe), Manganese

(Mn), Molybdenum (Mo), Copper (Cu), Zinc (Zn) and Boron (B).

If an organo-mineral fertilizer contains a substance, or one of the substances in the mixture, which is

intended to enhance the long-term availability to plants of micronutrients in the EU fertilizing product,

that substance is either a chelating agent or a complexing agent.
The chelating agents are divided into two groups :
— Group 1: EDTA, DTPA, HEEDTA, IDHA and [S,S]-EDDS;

— Group 2: Chelating agents present in UVCB (unknown or variable composition, complex reaction

products and biological materials) chelates including [o,o] EDDHA, [o,p] EDDHA, [o,o] EDDHMA,

HBED and EDDHSA.

This document defines the test method to be used in order to measure the compliance with the

chelated fraction of a micronutrient in product function category (PFC) 1(B) (classified according to

Regulation (EU) 2019/1009 [9]) for organo-mineral fertilizers containing one or more chelating

agents of Group 2.
Abbreviated terms are described in Annex A.
---------------------- Page: 6 ----------------------
SIST-TS CEN/TS 17790:2023
CEN/TS 17790:2022 (E)
1 Scope

This document specifies a method for the determination of the chelated micronutrient content and the

chelated fraction of a micronutrient, in organo-mineral fertilizers, having an organic matrix based on

vegetal residues (cocoa shells, grape residue, soybean residue, etc), algae extract, and animal meal

(feather, bones, blood, etc) and containing UVCB, EDDHA, EDDHMA, HBED, EDDHSA micronutrients

by the treatment with a cation exchange resin.

The limit of determination of the chelated micronutrient content highly depends on the specific

electrical conductivity of the sample, on the amount of nutrient present, and varies between 0,005 %

in simple matrices with high amounts of micronutrient, and 0,5 % in more complex cases (see 9.1).

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 12944-1, Fertilizers and liming materials — Vocabulary — Part 1: General terms

EN 12944-2, Fertilizers and liming materials — Vocabulary — Part 2: Terms relating to fertilizers

EN 16962, Fertilizers — Extraction of water soluble micro-nutrients in fertilizers and removal of organic

compounds from fertilizer extracts

EN 16963, Fertilizers — Determination of boron, cobalt, copper, iron, manganese, molybdenum and zinc

using ICP-AES

EN 16965, Fertilizers — Determination of cobalt, copper, iron, manganese and zinc using flame atomic

absorption spectrometry (FAAS)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 12944-1 and EN 12944-2 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
chelated fraction of a micronutrient

ratio of chelated micronutrient content compared to the total water-soluble micronutrient content

Note 1 to entry: The chelated fraction is expressed as a percentage.
---------------------- Page: 7 ----------------------
SIST-TS CEN/TS 17790:2023
CEN/TS 17790:2022 (E)
4 Principle

The sample is extracted with water and the extract adjusted to a neutral pH. The chelated forms of an

element thus having a negative and/or neutral charge are not retained by an ion exchange resin of the

strong sulfonated cationic type, and are separated from the non-chelated forms, having a cationic

nature. The chelated forms are collected and their content determined by spectrometry, as well as the

water-soluble content.
5 Interferences

Any substance combining with a micronutrient to form a stable, negative or uncharged compound

(chelate or complex) at neutral pH, will prevent the retention by the resin, and account for a certain

degree of chelation. This is the case for many complexing agents, e.g. amino acids, citrate, and for

chelating agents other than ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylene-

diaminetetraacetic acid (HEEDTA), diethylenetriaminepentaacetic acid (DTPA), ethylediamine-di-(o-

hydroxyphenyl)acetic acid ([o,o] EDDHA), ethylenediamine-N,N’-di[(2-hydroxy-5-sulfophenyl)acetic

acid] (EDDHSA) and ethylediamine-di-(o-hydroxy-p-methylphenyl)acetic acid ([o,o] EDDHMA).

In order to determine the presence of the statutory chelating agents in the sample, EN 13368-1 [4] and

EN 13368-2 [5] should be applied.

In some cases, especially where complex fertilizer matrices with high amounts of phosphate are

handled, or where micronutrients with a low chelated fraction are present, slow precipitation

reactions can occur during the contact with the resin, causing equilibrium shifts, adsorption,

decreasing the exchange capacity and leading to inaccurate and imprecise results. It is advised to

proceed as soon as possible with all steps. Highly unstable solutions cannot be considered.

6 Reagents
All reagents shall be of recognized analytical grade.
6.1 Water
All water used should conform to EN ISO 3696 and be degassed.
6.2 Sulfonated cationic exchange resin

Polystyrene divinylbenzene (PS-DVB) copolymer, slightly crosslinked (mass fraction of DVB less than

or equal to 8 %), in sodic or protonic form, free from Co, Cu, Fe, Mn, and Zn .
6.2.1 Preparation and determination of exchange capacity

Protonate the resin prior to use, transform to the sodic form, to eliminate any contamination and

measure the cationic exchange capacity (CEC) of the sodic resin in wet form as follows:

Transfer 50 g of resin to a 500 ml beaker and add 250 ml of hydrochloric acid solution (6.4).

Place on a magnetic stirrer. After 1 h of moderate stirring, the suspension i
...

SLOVENSKI STANDARD
kSIST-TS FprCEN/TS 17790:2021
01-december-2021
[Not translated]

Organo-mineral fertilizers - Determination of the chelated micronutrient content and the

chelated fraction of micronutrients by treatment with a cation exchange resin
Organisch-mineralische Düngemittel - Bestimmung des Gehalts an chelatisierten
Spurennährstoffen und des chelatisierten Anteils an Spurennährstoffen durch
Behandlung mit einem Kationenaustauscherharz
Ta slovenski standard je istoveten z: FprCEN/TS 17790
ICS:
65.080 Gnojila Fertilizers
kSIST-TS FprCEN/TS 17790:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
kSIST-TS FprCEN/TS 17790:2021
---------------------- Page: 2 ----------------------
kSIST-TS FprCEN/TS 17790:2021
FINAL DRAFT
TECHNICAL SPECIFICATION
FprCEN/TS 17790
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
October 2021
ICS 65.080
English Version
Organo-mineral fertilizers - Determination of the chelated
micronutrient content and the chelated fraction of
micronutrients by treatment with a cation exchange resin
Organisch-mineralische Düngemittel - Bestimmung des
Gehalts an chelatisierten Spurennährstoffen und des
chelatisierten Anteils an Spurennährstoffen durch
Behandlung mit einem Kationenaustauscherharz

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 17790:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
kSIST-TS FprCEN/TS 17790:2021
FprCEN/TS 17790:2021 (E)
Contents Page

European foreword ....................................................................................................................................... 3

Introduction ..................................................................................................................................................... 4

1 Scope ..................................................................................................................................................... 5

2 Normative references ..................................................................................................................... 5

3 Terms and definitions .................................................................................................................... 5

4 Principle .............................................................................................................................................. 6

5 Interferences ..................................................................................................................................... 6

6 Reagents .............................................................................................................................................. 6

7 Apparatus ............................................................................................................................................ 8

8 Sampling and sample preparation............................................................................................. 8

9 Procedure ........................................................................................................................................... 8

9.1 Extraction of the sample ................................................................................................................ 8

9.2 pH adjustment ................................................................................................................................... 9

9.3 Ion exchange separation ............................................................................................................... 9

9.4 Spectrometric determination .................................................................................................... 10

9.5 Water soluble micronutrient content determination ...................................................... 10

10 Expression of results ..................................................................................................................... 10

10.1 Chelated micronutrient content in the fertilizer ................................................................ 10

10.2 Chelated fraction of a micronutrient in the fertilizer ....................................................... 10

11 Test report ........................................................................................................................................ 11

Annex A (informative) Complete names of chelating agents ...................................................... 12

Bibliography ................................................................................................................................................... 13

---------------------- Page: 4 ----------------------
kSIST-TS FprCEN/TS 17790:2021
FprCEN/TS 17790:2021 (E)
European foreword

This document (FprCEN/TS 17790:2021) 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 Standardization Request given to CEN by the European

Commission and the European Free Trade Association.
---------------------- Page: 5 ----------------------
kSIST-TS FprCEN/TS 17790:2021
FprCEN/TS 00260292:2021 (E)
Introduction

Micronutrients are considered to be, in plant nutrition, a number of elements known to be needed in

small amounts for proper plant growth and development. The most common are Iron (Fe), Manganese

(Mn), Molybdenum (Mo), Copper (Cu), Zinc (Zn) and Boron (B).

If an organo-mineral fertilizer contains a substance, or one of the substances in the mixture, which is

intended to enhance the long term availability to plants of micronutrients in the EU fertilizing product,

that substance is either a chelating agent or a complexing agent.
The chelating agents are divided into two groups :
— Group 1: EDTA, DTPA, HEEDTA, IDHA and [S,S]-EDDS;

— Group 2: Chelating agents present in UVCB (unknown or variable composition, complex reaction

products and biological materials) chelates including [o,o] EDDHA, [o,p] EDDHA, [o,o] EDDHMA,

HBED and EDDHSA.

This document defines the test method to be used in order to measure the compliance with the

chelated fraction of a micronutrient in product function category (PFC) 1(B) (classified according to

Regulation (EU) 2019/1009 [9]) for organo-mineral fertilizers containing one or more chelating

agents of Group 2.
Abbreviated terms are described in Annex A.
---------------------- Page: 6 ----------------------
kSIST-TS FprCEN/TS 17790:2021
FprCEN/TS 17790:2021 (E)
1 Scope

This document specifies a method for the determination of the chelated micronutrient content and the

chelated fraction of a micronutrient, in organo-mineral fertilizers, having an organic matrix based on

vegetal residues (cocoa shells, grape residue, soybean residue, etc), algae extract, and animal meal

(feather, bones, blood, etc) and containing UVCB, EDDHA, EDDHMA, HBED, EDDHSA micronutrients

by the treatment with a cation exchange resin.

The limit of determination of the chelated micronutrient content highly depends on the specific

electrical conductivity of the sample, on the amount of nutrient present, and varies between 0,005 %

in simple matrices with high amounts of micronutrient, and 0,5 % in more complex cases (see 9.1).

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 12944-1, Fertilizers and liming materials and soil improvers - Vocabulary - Part 1: General terms

EN 12944-2, Fertilizers and liming materials and soil improvers - Vocabulary - Part 2: Terms relating to

fertilizers

EN 16962, Fertilizers - Extraction of water soluble micro-nutrients in fertilizers and removal of organic

compounds from fertilizer extracts

EN 16963, Fertilizers - Determination of boron, cobalt, copper, iron, manganese, molybdenum and zinc

using ICP-AES

EN 16965, Fertilizers - Determination of cobalt, copper, iron, manganese and zinc using flame atomic

absorption spectrometry (FAAS)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 12944-1 and EN 12944-2 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
chelated fraction of a micronutrient

ratio of chelated micronutrient content compared to the total water-soluble micronutrient content

Note 1 to entry: The chelated fraction is expressed as a percentage.
---------------------- Page: 7 ----------------------
kSIST-TS FprCEN/TS 17790:2021
FprCEN/TS 00260292:2021 (E)
4 Principle

The sample is extracted with water and the extract adjusted to a neutral pH. The chelated forms of an

element thus having a negative and/or neutral charge are not retained by an ion exchange resin of the

strong sulfonated cationic type, and are separated from the non-chelated forms, having a cationic

nature. The chelated forms are collected and their content determined by spectrometry, as well as the

water-soluble content.
5 Interferences

Any substance combining with a micronutrient to form a stable, negative or uncharged compound

(chelate or complex) at neutral pH, will prevent the retention by the resin, and account for a certain

degree of chelation. This is the case for many complexing agents, e.g. amino acids, citrate, and for

chelating agents other than ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylene-

diaminetetraacetic acid (HEEDTA), diethylenetriaminepentaacetic acid (DTPA), ethylediamine-di-(o-

hydroxyphenyl)acetic acid (o,oEDDHA) and ethylediamine-di-(o-hydroxy-p-methylphenyl)acetic acid

(o,oEDDHMA).

In order to determine the presence of the statutory chelating agents in the sample, EN 13368-1 [4] and

EN 13368-2 [5] should be applied.

In some cases, especially where complex fertilizer matrices with high amounts of phosphate are

handled, or where micronutrients with a low chelated fraction are present, slow precipitation

reactions can occur during the contact with the resin, causing equilibrium shifts, adsorption,

decreasing the exchange capacity and leading to inaccurate and imprecise results. It is advised to

proceed as soon as possible with all steps. Highly unstable solutions cannot be considered.

6 Reagents
All reagents shall be of recognized analytical grade.
6.1 Water
All water used should conform to EN ISO 3696 and be degassed.
6.2 Sulfonated cationic exchange resin

Polystyrene divinylbenzene (PS-DVB) copolymer, slightly crosslinked (mass fraction of DVB less than

or equal to 8 %), in sodic or protonic form, free from Co, Cu, Fe, Mn, and Zn .
6.2.1 Preparation and determination of exchange capacity

Protonate the resin prior to use, transform to the sodic form, to eliminate any contamination and

measure the cationic exchange capacity (CEC) of the sodic resin in wet form as follows:

Transfer 50 g of resin to a 500 ml beaker and add 250 ml of hydrochloric acid solution (6.4).

Place on a magnetic stirrer. After 1 h of moderate stirring, the suspension is transferred onto the sieve

(6.1). The resin is recovered and transferred back to the beaker. The acidification and separation

operations are repeated as described. At the end of the second operation, the protonated resin present

on the sieve is washed thoroughly with water until the rinsing water is free from chloride when tested

with silver nitrate.

Dowex 50 x 4-400, Amberlite IR 120 or equivalent are examples of suitable products available commercially.

This information is given for the convenience of users of this document and does not constitute an endorsement

by CEN of these products.
---------------------- Page: 8 ----------------------
kSIST-TS FprCEN/T
...

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