CEN/TS 17723:2022

SLOVENSKI STANDARD
01-februar-2023
Rastlinski biostimulanti - Določevanje klorida
Plant biostimulants - Determination of chloride
Pflanzen-Biostimulanzien - Chloridbestimmung
Biostimulants des végétaux - Dosage des chlorures
Ta slovenski standard je istoveten z: CEN/TS 17723:2022
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TS 17723
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
March 2022
TECHNISCHE SPEZIFIKATION
ICS 65.080
English Version
Plant biostimulants - Determination of chloride
Biostimulants des végétaux - Dosage des chlorures Biostimulanzien für die pflanzliche Anwendung -
Chloridbestimmung
This Technical Specification (CEN/TS) was approved by CEN on 3 January 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 17723:2022 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 . 5
5 Principle . 5
5.1 General. 5
5.2 Interferences . 5
6 Reagents . 6
7 Apparatus . 6
8 Procedure . 6
8.1 Measurement temperature . 6
8.2 Preparation of the test portion . 6
8.3 Blank test . 7
8.4 Titration . 7
8.4.1 Test portion (sample) . 7
8.4.2 Blank test . 7
8.5 Recovery test . 7
9 Expression of results . 7
10 Test report . 8
Annex A (informative) Preparation and standardization of 0,1 mol/l silver nitrate solution
................................................................................................................................................................... 10
Annex B (informative) More exact calculation of the equivalence point of the titration . 11
Bibliography . 12

European foreword
This document (CEN/TS 17723:2022) has been prepared by Technical Committee CEN/TC 455 “Plant
Biostimulants”, the secretariat of which is held by AFNOR.
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
This document was prepared by the experts of CEN/TC 455 “Plant Biostimulants”. The European
Committee for Standardization (CEN) was requested by the European Commission (EC) to draft
European standards or European standardization deliverables to support the implementation of
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 (“FPR” or “Fertilising Products
Regulation”). This standardization request, presented as M/564, also contributes to the Communication
on “Innovating for Sustainable Growth: A Bio economy for Europe”. Working Group 5 “Labelling and
denominations”, was created to develop a work program as part of this standardization request.
Technical Committee CEN/TC 455 “Plant Biostimulants” was established to carry out the work program
that will prepare a series of standards. The interest in biostimulants has increased significantly in Europe
as a valuable tool to use in agriculture. Standardization was identified as having an important role in
order to promote the use of biostimulants. The work of CEN/TC 455 seeks to improve the reliability of
the supply chain, thereby improving the confidence of farmers, industry, and consumers in biostimulants,
and will promote and support commercialization of the European biostimulant industry.
To improve the market of EU Plant Biostimulants products, they should be labelled in accordance with
the labelling requirements set out in Annex III of Regulation 2019/1009 [5], which prescribes that the
−
phrase “poor in chloride” or similar may only be used if the chloride (Cl ) content is below 30 g/kg of dry
matter.
This means that the manufacturer has the possibility to note on the label that the plant biostimulant is
“poor in chloride”, only if the manufacturer has done the analysis and the chloride content is well below
30 g/kg of dry matter.
The trend of the last few years is to reduce the use of harmful chemicals both for operators and the
environment, favouring the use of the most advanced technologies that have a lower impact; therefore,
the potentiometric is preferable to other techniques.
Furthermore, the potentiometric method is not influenced by interferences due to colour or turbidity of
the sample solution.
WARNING — Persons using this document should be familiar with usual laboratory practice. This
document does not purport to address all of the safety issues, if any, associated with its use. It is the
responsibility of the user to establish appropriate health and safety practices and to ensure compliance
with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted according to this document are carried out
by suitably trained staff.
1 Scope
-
This document specifies a potentiometric method for the determination of chloride (Cl ) content in the
presence or in the absence of organic material. This method is applicable to plant biostimulants.
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.
CEN/TS 17702-2, Plant biostimulants - Sampling and sample preparation - Part 2: Sample preparation
CEN/TS 17724, Plant biostimulants - Terminology
EN ISO 3696:1995, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TS 17724 and the following
apply.
3.1
chloride content of plant biostimulants
mass fraction of chlorides, expressed in g/kg of dry matter, determined in accordance with the procedure
described in this document
4 Sampling
Sampling is not part of this method specified in this document. A recommended sampling method is given
in CEN/TS 17702-1.
Laboratory sample preparation shall be carried out in accordance with CEN/TS 17702-2. Homogeneous
samples are recommended.
5 Principle
5.1 General
Soluble chlorides are extracted from the sample with water containing nitric acid. The chloride content
of the solution is titrated with silver nitrate standard solution and the end point is determined
potentiometrically by using either a silver ion selective electrode plus a reference electrode or a
combined electrode.
5.2 Interferences
-
Maintain the sample at a lower pH can avoid the silver ion interact with OH to form silver oxide (Ag O)
precipitation, minimize other anionic ions interference with the AgCl formation, and improve the binding
between the titrant and the analyte.
6 Reagents
Use only reagents of recognized analytical grade.
6.1 Water
Water free from chlorides in compliance with quality grade 2, according to EN ISO 3696:1995 shall be
used.
6.2 Nitric acid solution
Nitric acid solution: dilute 1:1 concentrated nitric acid (70 %) with water (6.1).
6.3 Silver nitrate standard solution, c = 0,1 mol/l solution
Silver nitrate solution, 0,1 mol/l in water (6.1). Use commercially available silver nitrate solution with
certified concentration or prepare and standardize a solution according to the instructions in Annex A.
7 Apparatus
Normally, automatic titrators are used. This method describes manual titrations.
Ordinary laboratory equipment and the following are required:
7.1 Electromagnetic stirrer and polytetrafluoroethylene (PTFE) coated magnetic bars.
7.2 Glass burettes class A reading with accuracy of 0,02 ml or automatic pipette with accuracy of
0,002 ml.
7.3 One-mark volumetric glass flask Class A, capacity 150 ml, 500 ml and 1 000 ml and graduated glass
flask Class A, capacity 100 ml.
7.4 Glass beaker, capacity 300 ml.
7.5 Glass conical (Erlenmeyer) flask, capacity 250 ml.
7.6 Potentiometer, with reading accuracy of 0,1 mV, equipped with an electrode suitable for the
measurement of chloride (e.g. a silver electrode) and a reference electrode (e.g. a mercury(I) sulfate
electrode). Alternatively, use a suitable combination electrode.
8 Procedure
8.1 Measurement temperature
In order to reduce the effects of thermal and electric hysteresis, take care that the temperatures of the
electrodes, the water used for washings, the standard solutions and the test solution are as close to each
other as possible. The temperatures of the standard solutions and the test solution shall not differ by
more than 1 °C. The measurement temperature should be 25 °C whenever possible.
8.2 Preparation of the test portion
Homogenize solid samples without addition of water. Mix liquid samples well.
Depending on the expected chloride content, with an accuracy of 0,1 mg, weigh 1 g to 10 g of sample into
a beake
...