CEN/TS 17784-1:2022

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

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.

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

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.
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.

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.
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
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 solu
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