Organo-mineral fertilizers - Identification of complexing agents - Part 1: Method using UV-Vis spectrophotometry and gravimetry

This document specifies two methods required for the identification of lignosulfonate by UV-Vis spectrophotometry (method A) and gravimetry (method B) in organo-mineral fertilizers.
NOTE   Lignosulfonate, as a complexing agent, is a natural polymer produced as a by-product of the sulfite method for manufacturing paper from wood pulp in the paper industry. As a natural polymer, it presents a poorly defined and variable chemical structure. It is an intricate mixture of small- to moderate-sized polymeric compounds with sulfonate groups attached to the molecule, and diverse complexing capacity.

Organisch-mineralische Düngemittel - Identifizierung von Komplexbildnern - Teil 1: Verfahren mittels UV/VIS-Spektralphotometrie und Gravimetrie

Dieses Dokument legt zur Identifizierung von Ligninsulfonaten in organisch-mineralischen Düngemitteln zwei Verfahren fest, und zwar mittels UV/VIS Spektralphotometrie (Verfahren A) und Gravimetrie (Verfahren B).
ANMERKUNG   Ligninsulfonat als Komplexbildner ist ein natürliches Polymer, das in der Papierindustrie als Neben-produkt des Sulfitverfahrens zur Herstellung von Papier aus Holzstoff anfällt. Als ein natürliches Polymer weist es eine kaum definierte und variable chemische Struktur auf. Es handelt sich um ein kompliziertes Gemisch aus kleinen bis mittel¬großen polymeren Verbindungen mit Sulfonatgruppen, die an das Molekül gebunden sind, sowie mit unterschiedlichem Komplexbildungsvermögen.

Engrais organo-minéraux - Identification des agents complexants - Partie 1 : Méthode utilisant la spectrophotométrie UV-Vis et la gravimétrie

Le présent document spécifie deux méthodes requises pour l’identification du lignosulfonate par spectrophotométrie UV-Vis (méthode A) et par gravimétrie (méthode B) dans les engrais organo-minéraux.
NOTE   Le lignosulfonate, en tant qu’agent complexant, est un polymère naturel qui est un sous-produit de la méthode des sulfites utilisée pour la fabrication de papier à partir de pâte de bois dans l’industrie papetière. En tant que polymère naturel, il présente une structure chimique mal définie et variable. Il s’agit d’un mélange complexe de composés polymères de taille petite à moyenne, avec des groupes sulfonate attachés à la molécule, ayant une capacité complexante variable.

Organsko-mineralna gnojila - Identifikacija sredstev za kompleksiranje - 1. del: Metoda z UV/VIS spektrofotometrijo in gravimetrijo

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 17784-1:2023
01-februar-2023
Organsko-mineralna gnojila - Identifikacija sredstev za kompleksiranje - 1. del:
Metoda z UV/VIS spektrofotometrijo in gravimetrijo

Organo-mineral fertilizers - Identification of complexing agents - Part 1: Method using

UV-Vis spectrophotometry and gravimetry

Organisch-mineralische Düngemittel - Identifizierung von Komplexbildnern - Teil 1:

Verfahren mittels UV/VIS-Spektralphotometrie und Gravimetrie

Engrais organo-minéraux - Identification des agents complexants - Partie 1 : Méthode

utilisant la spectrophotométrie UV-Vis et la gravimétrie
Ta slovenski standard je istoveten z: CEN/TS 17784-1:2022
ICS:
65.080 Gnojila Fertilizers
SIST-TS CEN/TS 17784-1:2023 en,fr,de

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

---------------------- Page: 1 ----------------------
SIST-TS CEN/TS 17784-1:2023
---------------------- Page: 2 ----------------------
SIST-TS CEN/TS 17784-1:2023
CEN/TS 17784-1
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
April 2022
TECHNISCHE SPEZIFIKATION
ICS 65.080
English Version
Organo-mineral fertilizers - Identification of complexing
agents - Part 1: Method using UV-Vis spectrophotometry
and gravimetry

Engrais organo-minéraux - Identification des agents Organisch-mineralische Düngemittel - Identifizierung

complexants - Partie 1 : Méthode utilisant la von Komplexbildnern - Teil 1: Verfahren mittels

spectrophotométrie UV-Vis et la gravimétrie UV/VIS-Spektralphotometrie und Gravimetrie

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 17784-1:2022 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST-TS CEN/TS 17784-1:2023
CEN/TS 17784-1:2022 (E)
Contents Page

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

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

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

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

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

4 Sampling and sample preparation ................................................................................................. 5

5 Method A: Determination of phenolic hydroxyl content and 232,5 nm absorbance for

the identification of lignosulfonates .............................................................................................. 5

5.1 Principle ................................................................................................................................................... 5

5.2 Reagents ................................................................................................................................................... 6

5.3 Apparatus ................................................................................................................................................ 6

5.4 Procedure ................................................................................................................................................ 7

5.5 Calculation ............................................................................................................................................... 7

6 Method B: Determination of organic sulfur content for the identification of

lignosulfonates ...................................................................................................................................... 9

6.1 Principle ................................................................................................................................................... 9

6.2 Reagents ................................................................................................................................................... 9

6.3 Apparatus .............................................................................................................................................. 10

6.4 Procedure .............................................................................................................................................. 11

6.5 Calculation ............................................................................................................................................. 12

7 Expression of the results .................................................................................................................. 12

7.1 Relative phenolic hydroxyl content ............................................................................................. 12

7.2 Relative organic sulfur content...................................................................................................... 13

8 Test report ............................................................................................................................................. 13

Bibliography ....................................................................................................................................................... 14

---------------------- Page: 4 ----------------------
SIST-TS CEN/TS 17784-1:2023
CEN/TS 17784-1:2022 (E)
European foreword

This document (CEN/TS 17784-1:2022) 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 17784-1:2023
CEN/TS 17784-1:2022 (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 can be either a chelating agent or a complexing agent.

The incorporation of lignosulfonates as complexing agents in organo-mineral fertilizers is intended to

enhance the long term availability to plants of micronutrients in such EU fertilizing products.

---------------------- Page: 6 ----------------------
SIST-TS CEN/TS 17784-1:2023
CEN/TS 17784-1:2022 (E)
1 Scope

This document specifies two methods required for the identification of lignosulfonate by UV-Vis

spectrophotometry (method A) and gravimetry (method B) in organo-mineral fertilizers.

NOTE Lignosulfonate, as a complexing agent, is a natural polymer produced as a by-product of the sulfite

method for manufacturing paper from wood pulp in the paper industry. As a natural polymer, it presents a poorly

defined and variable chemical structure. It is an intricate mixture of small- to moderate-sized polymeric compounds

with sulfonate groups attached to the molecule, and diverse complexing capacity.
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 ISO 3696, Water for analytical laboratory use — Specification and test methods (ISO 3696)

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
complexing agent

organic substance forming a flat or steric structure with one di- or tri-valent transition metal cation (zinc

(Zn), copper (Cu), iron (Fe), manganese (Mn) or cobalt (Co))
4 Sampling and sample preparation

Sampling and sample preparation are not part of the method specified in this document.

Recommended sampling methods are given in EN 1482-1 and, for sample preparation, in EN 1482-2.

5 Method A: Determination of phenolic hydroxyl content and 232,5 nm
absorbance for the identification of lignosulfonates
5.1 Principle

The method for the determination of the phenolic hydroxyl content is based on the ultraviolet absorption

of phenols in alkaline solution (phenolate). The absorbance of an alkaline solution of the sample is

measured directly against an acid solution of the same sample. The phenolic hydroxyl content of the

sample is calculated from the molar extinction coefficient maximum of the resulting curve and the molar

extinction coefficient of reference compounds determined in the same way.
---------------------- Page: 7 ----------------------
SIST-TS CEN/TS 17784-1:2023
CEN/TS 17784-1:2022 (E)

The determination of the absorbance at 232,5 nm is normally considered the method for the

quantification of lignosulfonates, providing that no other ultraviolet absorbing organic compounds are

present.
NOTE For additional information, see [5] and [6].

WARNING — Users of this document should be familiar with normal 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.
5.2 Reagents
All reagents shall be of recognized analytical grade.
5.2.1 Water.

All water used shall be conform to EN ISO 3696, be degassed and be free of organic contaminants.

5.2.2 Hydrochloric acid solution, substance concentration c(HCl)= 6 mol/l.
5.2.3 Sodium hydroxide solution, c(NaOH)= 0,1 mol/l.
5.2.4 Analytical grade fine mesh strong cation exchange resin.

Styrene/DVB type, 8 % crosslinked . Hydrogen form. Functional group: sulphonic acid. Nominal

exchange capacity: 1,7 mmol/ml. Particle size: 50 to 100 mesh.
5.3 Apparatus
Usual laboratory equipment, glassware, and in particular the following:
5.3.1 Magnetic stirrer.
5.3.2 Balance, capable of weighing to the nearest 1 mg.
5.3.3 Filter paper, pore size 15 µm to 20 µm.
5.3.4 pH-meter, equipped with a glass electrode.
5.3.5 UV-Vis spectrophotometer, equipped with 10 mm quartz cells.

Biorad AG® 50 W-X8 (50-100) Cat. No. 142-1431 is an example of a suitable product commercially available. This

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

of this product.

Albet 412 filter paper or equivalent is an example of a suitable product commercially available. This information

is given for the convenience of users of this document and does not constitute an endorsement by CEN of this

product
---------------------- Page: 8 ----------------------
SIST-TS CEN/TS 17784-1:2023
CEN/TS 17784-1:2022 (E)
5.4 Procedure
5.4.1 Preparation of stock solution

Weigh, to the nearest 1 mg, 0,15 g to 0,20 g of the sample in a 100 ml beaker. Add 4 g of cation exchange

resin (5.2.4) and about 20 ml to 25 ml of water. Allow the ion-exchange process to take place for 20 min,

ensuring proper mixing by means of a magnetic stirrer.

Filter (5.3.3) into a 250 ml volumetric flask to remove the resin and thoroughly wash the filter. Dilute to

the mark with water (stock solution).
5.4.2 Solution A (acid)

Take an aliquot (40 ml ± 5 ml) of the stock solution into a 100 ml beaker and adjust pH between 2,0 and

2,2 with few drops of hydrochloric acid solution (5.2.2). Pipette 5 ml of the pH-adjusted solution into a

50 ml volumetric flask and dilute to the mark. Final concentration 0,06 g/l to 0,08 g/l.

5.4.3 Solution B (basic)

Pipette 5 ml of the stock solution into a 50 ml volumetric flask. Add 10 ml of sodium hydroxide solution

(5.2.3) to adjust pH over 11,0. Dilute to the mark. Final concentration 0,06 g/l to 0,08 g/l. Check that the

pH of the solution is over 11,0, if not prepare solution B adding more sodium hydroxide.

5.4.4 Solution C

Pipette 10 ml of the stock solution into a 100 ml beaker and fill with water to 60 ml ± 5 ml. Adjust the pH

of the solution between 4,0 and 5,0 with t
...

SLOVENSKI STANDARD
kSIST-TS FprCEN/TS 17784-1:2021
01-december-2021
Organsko-mineralna gnojila - Identifikacija kompleksirajočih agensov - 1. del:
Metoda z ultravijolično in vidno (UV/VIS) spektrofotometrijo in gravimetrijo

Organo-mineral fertilizers - Identification of complexing agents - Part 1: Method using

UV-Vis spectrophotometry and gravimetry

Organisch-mineralische Düngemittel - Identifizierung von Komplexbildnern - Teil 1:

Verfahren mittels UV/VIS-Spektralphotometer und Gravimetrie
Ta slovenski standard je istoveten z: FprCEN/TS 17784-1
ICS:
65.080 Gnojila Fertilizers
kSIST-TS FprCEN/TS 17784-1:2021 en,fr,de

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

---------------------- Page: 1 ----------------------
kSIST-TS FprCEN/TS 17784-1:2021
---------------------- Page: 2 ----------------------
kSIST-TS FprCEN/TS 17784-1:2021
FINAL DRAFT
TECHNICAL SPECIFICATION
FprCEN/TS 17784-1
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
October 2021
ICS 65.080
English Version
Organo-mineral fertilizers - Identification of complexing
agents - Part 1: Method using UV-Vis spectrophotometry
and gravimetry
Organisch-mineralische Düngemittel - Identifizierung
von Komplexbildnern - Teil 1: Verfahren mittels
UV/VIS-Spektralphotometer und Gravimetrie

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 17784-1:2021 E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
kSIST-TS FprCEN/TS 17784-1:2021
FprCEN/TS 17784-1:2021 (E)
Contents Page

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

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

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

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

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

4 Sampling and sample preparation ........................................................................................................... 5

5 Method A: Determination of phenolic hydroxyl content and 232,5 nm absorption for the

identification of lignosulfonates ............................................................................................................... 5

5.1 Principle ............................................................................................................................................................. 5

5.2 Reagents ............................................................................................................................................................. 6

5.3 Apparatus .......................................................................................................................................................... 6

5.4 Procedure .......................................................................................................................................................... 6

5.5 Calculation ......................................................................................................................................................... 7

6 Method B: Determination of organic sulfur content for the identification of lignosulfonates

............................................................................................................................................................................... 9

6.1 Principle ............................................................................................................................................................. 9

6.2 Reagents ............................................................................................................................................................. 9

6.3 Apparatus ....................................................................................................................................................... 10

6.4 Procedure ....................................................................................................................................................... 11

6.5 Calculation ...................................................................................................................................................... 12

7 Expression of the results ........................................................................................................................... 12

7.1 Relative phenolic hydroxyl content ...................................................................................................... 12

7.2 Relative organic sulfur content............................................................................................................... 13

8 Test report ...................................................................................................................................................... 13

Bibliography ................................................................................................................................................................ 14

---------------------- Page: 4 ----------------------
kSIST-TS FprCEN/TS 17784-1:2021
FprCEN/TS 17784-1:2021 (E)
European foreword

This document (FprCEN/TS 17784-1:2021) 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 17784-1:2021
FprCEN/TS 17784-1:2021 (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 can be either a chelating agent or a complexing agent.

The incorporation of lignosulfonates as complexing agents in organo-mineral fertilizers is intended to

enhance the long term availability to plants of micronutrients in such EU fertilizing products.

WARNING — Users of this document should be familiar with normal 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.
---------------------- Page: 6 ----------------------
kSIST-TS FprCEN/TS 17784-1:2021
FprCEN/TS 17784-1:2021 (E)
1 Scope

This document specifies two methods required for the identification of lignosulfonate by UV-Vis

spectrophotometry (method A) and gravimetry (method B) in organo-mineral fertilizers.

NOTE Lignosulfonate, as a complexing agent, is a natural polymer produced as a by-product of the sulfite

method for manufacturing paper from wood pulp in the paper industry. As a natural polymer, it presents a poorly

defined and variable chemical structure. It is an intricate mixture of small- to moderate-sized polymeric compounds

with sulfonate groups attached to the molecule, and diverse complexing capacity.
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 ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696)

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
complexing agent

organic substance forming a flat or steric structure with one di- or tri-valent transition metal cation (zinc

(Zn), copper (Cu), iron (Fe), manganese (Mn) or cobalt (Co))
4 Sampling and sample preparation

Sampling and sample preparation are not part of the method specified in this document.

Recommended sampling methods are given in EN 1482-1 and, for sample preparation, in EN 1482-2.

5 Method A: Determination of phenolic hydroxyl content and 232,5 nm
absorption for the identification of lignosulfonates
5.1 Principle

The method for the determination of the phenolic hydroxyl content is based on the ultraviolet absorption

of phenols in alkaline solution (phenolate). The absorbance of an alkaline solution of the sample is

measured directly against an acid solution of the same sample. The phenolic hydroxyl content of the

sample is calculated from the molar extinction coefficient maximum of the resulting curve and the molar

extinction coefficient of reference compounds determined in the same way.
---------------------- Page: 7 ----------------------
kSIST-TS FprCEN/TS 17784-1:2021
FprCEN/TS 17784-1:2021 (E)

The determination of the absorption at 232,5 nm is normally considered the method for the

quantification of lignosulfonates, providing that no other ultraviolet absorbing organic compounds are

present.
NOTE For additional information, see [5] and [6].
5.2 Reagents
All reagents shall be of recognized analytical grade.
5.2.1 Water.

All water used should conform to EN ISO 3696, be degassed and be free of organic contaminants.

5.2.2 Hydrochloric acid solution, substance concentration c(HCl)= 6 mol/l.
5.2.3 Sodium hydroxide solution, c(NaOH)= 0,1 mol/l.
5.2.4 Analytical grade fine mesh strong cation exchange resin.

Styrene/DVB type, 8 % crosslinked . Hydrogen form. Functional group: sulphonic acid. Nominal

exchange capacity: 1,7 mmol/ml. Mesh: 50 to 100.
5.3 Apparatus
Usual laboratory equipment, glassware, and in particular the following:
5.3.1 Magnetic stirrer.
5.3.2 Balance, capable of weighing to the nearest 1 mg.
5.3.3 Filter paper, pore size 15 µm to 20 µm .
5.3.4 pH-meter, equipped with a glass electrode.
5.3.5 UV-Vis spectrophotometer, equipped with 10 mm quartz cells.
5.4 Procedure
5.4.1 Preparation of stock solution

Weigh, to the nearest 1 mg, 0,15 g to 0,20 g of the sample in a 100 ml beaker. Add 4 g of cation exchange

resin (5.2.4) and about 20 ml to 25 ml of water. Allow the ion-exchange process to take place for 20 min,

ensuring proper mixing by means of a magnetic stirrer.

Filter (5.3.3) into a 250 ml volumetric flask to remove the resin and thoroughly wash the filter. Dilute to

the mark with water (stock solution).

Biorad AG® 50 W-X8 (50-100) Cat. No. 142-1431 is an example of a suitable product commercially available. This

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

of this product.

Albet 412 filter paper or equivalent is an example of a suitable product commercially available. This information

is given for the convenience of users of this document and does not constitute an endorsement by CEN of this

product.
---------------------- Page: 8 ----------------------
kSIST-TS FprCEN/TS 17784-1:2021
FprCEN/TS 17784-1:2021 (E)
5.4.2 Solution A (acid)

Take an aliquot (40 ml ± 5 ml) of the stock solution into a 100 ml beaker and adjust pH between 2,0 and

2,2 with few drops of hydrochloric acid solution (5.2.2). Pipette 5 ml of the pH-adjusted solution into a

50 ml volumetric flask and dilute to the mark. Final concentration 0,06 g/l to 0,08 g/l.

5.4.3 Solution B (basic)

Pipette 5 ml of the stock solution into a 50 ml volumetric flask. Add 10 ml of sodium hydroxide solution

(5.2.3) to adjust pH over 11,0. Dilute to the mark. Final concentration 0,06 g/l to 0,08 g/l. Check that the

pH of the solution is over 11,0, if not prepare solution B adding more sodium hydroxide.

5.4.4 Solution C

Pipette 10 ml of the stock solution into a 100 ml beaker and fill with water to 60 ml ± 5 ml. Adjust the pH

of the solution between 4,0 and 5,0 with the sodium hydroxide solution (5.2.3). Transfer quantitatively

into a 100 ml volumetric flask, dilute to the mark with water and homogenize. See 5.4.6.

5.4.5 Measurement of phenolic hydroxyl content
Fill both cells in the UV spectrophotometer w
...

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