prEN 18254

SLOVENSKI STANDARD
01-december-2025
Izboljševalci tal in rastni substrati - Določanje anorganskega arzena
Soil improvers and growing media - Determination of the inorganic arsenic content
Bodenverbesserungsmittel und Kultursubstrate - Bestimmung des anorganischen
Arsengehalts
Amendements du sol et supports de culture - Détermination de la teneur en arsenic
inorganique
Ta slovenski standard je istoveten z: prEN 18254
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 65.080
English Version
Soil improvers and growing media - Determination of the
inorganic arsenic content
Amendements du sol et supports de culture - Bodenverbesserungsmittel und Kultursubstrate -
Détermination de la teneur en arsenic inorganique Bestimmung des anorganischen Arsengehalts
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 223.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

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, Türkiye 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 European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 18254:2025 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 Principle . 6
5 Reagents . 6
6 Apparatus . 8
7 Sampling . 9
8 Procedure . 9
8.1 Safety . 9
8.2 Sample preparation . 9
8.3 Water bath extraction . 9
8.4 Preparation of the calibration solutions . 10
8.5 Measurement . 10
8.5.1 General instrumental conditions . 10
8.5.2 HPLC-ICP/MS measurement of inorganic arsenic . 11
9 Calculation and expression of the results . 12
9.1 Integration of peaks . 12
9.2 Calculation of inorganic arsenic in the samples . 13
10 Test report . 13
11 Validation of the method . 14
11.1 Validation in accordance with ISO 5725-2. 14
11.2 Performance characteristics. 14
Annex A (informative) Examples of typical chromatographic separation . 15
Annex B (informative) Performance characteristics of the method . 17
Bibliography . 19

European foreword
This document (prEN 18254:2025) has been prepared by Technical Committee CEN/TC 223 “Soil
improvers and growing media”, the secretariat of which is held by NEN.
This document is currently submitted to the CEN Enquiry.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
Introduction
This document was prepared by the experts of CEN/TC 223 “Soil improvers and growing media”. 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 5 June 2019 laying down rules on the making available on the market of
EU fertilizing products (“FPR” or “Fertilising Products Regulation”) [8].
This standardization request, presented as M/564, also contributes to the Communication on “Innovating
for Sustainable Growth: A Bio economy for Europe”. The Working Group 4 “Analytical methods” was
requested to develop a work programme as part of this request. The technical committee CEN/TC 223
“Soil improvers and growing media” was requested to carry out the work programme that will prepare a
series of standards. The interest in soil improvers and growing media 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 soil improvers and growing media. The work of CEN/TC 223 seeks to
improve the reliability of the supply chain, thereby boosting the confidence of farmers, industry and
consumers in soil improvers and growing media and will promote and support commercialisation of the
European fertilizer industry. The preparation of this document is based on a standardization request to
CEN by the European Commission and the European Free Trade Association (Mandate M/564)
concerning the modernization of methods of analysis of fertilizers in the framework of Regulation (EU)
2019/1009 of the European Parliament and of the Council.
This document describes a procedure of extraction and measurement for the determination of inorganic
arsenic in growing media and soil improvers. The document is based on a mild acid oxidative extraction
of the arsenic species followed by liquid chromatography (High Performance Liquid Chromatography –
HPLC) or Ion Chromatography (IC) coupled to the element-specific detector Inductively Coupled Plasma
Mass Spectrometry (ICP-MS) for the determination of the mass fraction of inorganic arsenic.
The other standards developed for determination of inorganic arsenic content in animal feeding stuffs,
foodstuffs and plant biostimulants were studied as a basis of the described method [2], [3], [4], [5], [6].
1 Scope
This document specifies a method for extraction, separation, and determination of inorganic arsenic (iAs)
in growing media and soil improvers using anion-exchange high performance liquid chromatography
(HPLC) or ion chromatography (IC) coupled to ICP-MS.
This document is applicable to the fertilizing product blends where a blend is a mix of two or more
fertilising products belonging to the categories of fertilizers, liming material, soil improvers, growing
media, inhibitors and plant biostimulants, and where soil improvers and/or growing media are the
components with the highest percentage in the blend by mass or volume, or in the case of products in
liquid form by dry mass. If the soil improvers and/or growing media are not the components with the
highest percentage in the blend, the document relevant to the component with the highest percentage in
the blend applies. In case a blend is composed of fertilising products mixed in equal quantities, the user
of the document decides which standard to apply.
NOTE A soil improver consists of a single bulky (volume-building) component or a mix of bulky (volume-
building) components (for example peat, wood fibres, coconut coir, compost, expanded perlite).
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 17732:2022, Soil improvers and growing media - Terminology
EN 12579:2024, Soil improvers and growing media - Sampling
prEN 13040-1:2025, Soil improvers and growing media — Sample preparation — Part 1: Sample
preparation for chemical and physical tests, determination of dry matter content, moisture content and
laboratory bulk density
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TS 17732:2022 and the
following apply.
3.1
analyte
parameter to be determined
3.2
blank calibration solution
solution prepared in the same way as the calibration solution but leaving out the analytes
3.3
blank test solution
solution prepared in the same way as the test sample solution but omitting the test portion
3.4
calibration solution
solution used to calibrate the instrument, prepared from stock solutions by adding acids, buffer, reference
element and salts as needed
3.5
stock solution
solution with accurately known analyte concentration(s), prepared from pure chemicals
4 Principle
This document describes a method for the determination of inorganic arsenic in growing media and soil
improvers. Inorganic arsenic consists of arsenite As (III) and arsenate As (V). A representative test
portion of the sample is treated with a diluted nitric acid and hydrogen peroxide solution in a heated
water bath. By this means the sample is solubilised, arsenic species are extracted into solution and As (III)
is oxidized to As (V). The inorganic arsenic is selectively separated from other arsenic compounds using
anion exchange HPLC (High Performance Liquid Chromatography) coupled online to the element-specific
detector ICP-MS (Inductively Coupled Plasma Mass Spectrometer) for the determination of the mass
fraction of the inorganic arsenic. External calibration with solvent matrix-matched standards is used for
the quantification of the amount of the inorganic arsenic. Alternatively, IC (ion chromatography) coupled
to ICP-MS may be used.
A preliminary determination of the total arsenic in aqua regia extracts according to prEN 13650:2025 by
ICP-AES (WI 00223142:2025), can reduce the number of the samples where the determination of iAs is
necessary because if the content of aqua regia (total) extractable arsenic is lower than the legislative limit
for iAs (e.g. [8]) then the determination of iAs is not necessary.
To prove the compliance with existing limit values for inorganic arsenic in soil improvers and growing
media, there is the possibility to choose between:
— Using a testing method determining the aqua regia (total) extractable arsenic content, as long as the
result of the test shows a content below the limit value for inorganic arsenic. In such a case, it may be
safely assumed that soil improvers and growing media comply with the limit value for inorganic
arsenic.
— Using a testing method which determines only inorganic arsenic content.
In case aqua regia extractable (total) As is measured and is presented above or equal the legislative limit
for iAs, the content of inorganic As shall be determined according to this document.
5 Reagents
When using a method of high sensitivity such as ICP-MS and HPLC, the control of the blank levels of water,
acid and other reagents is very important. The reagents shall be of adequate purity and of recognized
analytical grade. The concentration of arsenic species in the reagents and water used shall be negligible
and low enough not to affect the results of the determination. Generally, ultra-pure water from a
purification system and nitric acid of minimum p.a. quality is recommended.
5.1 Water with an electrical conductivity not higher than 0,1 mS/m at 25 °C.
5.2 Nitric acid (HNO ), concentrated, ≥ 65 % (mass fraction), mass concentration of approximately
ρ (HNO ) 1,4 g/ml.
Use only nitric acid available with high purity (minimum p.a. quality) in order to avoid potential
contamination.
5.3 Hydrogen peroxide (H O ), not less than 30 % (mass fraction).
2 2
High purity is essential to avoid potential contamination. Commercially available hydrogen peroxide for
analysis should be tested for contamination of arsenic prior to use. It is necessary to prevent peroxide
degradation and ensure the stability of the solution.
5.4 Extraction solution, 0,1 mol/l HNO in 3 % (volume fraction) H O .
3 2 2
Add 6,5 ml of HNO (5.2) and thereafter 100 ml of hydrogen peroxide (5.3) into 800 ml water (5.1) in a
1 000 ml volumetric flask. Fill the flask to the mark with water (5.1). This solution is prepared on the day
of use.
It is recommended that the total volume needed for the analysis is estimated and only this amount is
produced in the day of use.
5.5 Ammonium carbonate ((NH ) CO ), mass fraction w ≥ 99,999 %, for preparation of the mobile
4 2 3
phase solution.
5.6 Aqueous ammonia (NH3(aq.)), mass fraction w ≥ 25 %, for adjustment of pH in the mobile phase.
5.7 Methanol (CH OH), HPLC grade, for preparation of the mobile phase solution.
5.8 Mobile phase, e.g. 50 mmol/l ammonium carbonate in 3 % (volume fraction) methanol at pH 10,3.
Dissolve 4,80 g of ammonium carbonate (5.5) in approximately 800 ml water (5.1). Adjust the pH to 10,3
with aqueous ammonia (5.6) and add 30 ml of methanol (5.7) and then fill up to 1 000 ml with water
(5.1). Prior to use filter the mobile phase solution through a 0,45 μm filter using a filtering device (6.4).
The optimal concentration of ammonium carbonate in the mobile phase depends on the analytical column
used (e.g. brand, particle size and dimensions) and should be verified in advance. The appropriate
concentration of ammonium carbonate (usually between 10 mmol/l to 50 mmol/l) is highly dependent
on the column used and is up to the discretion of the analyst. It should fulfil the criteria for sufficient
resolution of the arsenate peak.
Methanol is added to the mobile phase in order to enhance the signal intensity for arsenic. The
concentration of methanol to achieve the highest signal to noise ratio depends on the instrument used
and should be identified by the analyst.
Different mobile phase may be also used according to the instructions of the manufacturer of the column
but it is necessary to verify optimal separation conditions.
1 1
EXAMPLE For example, Agilent column G3154–65001 with a guard column G3154–65002 and
a recommended mobile phase for this column (dihydrogen potassium carbonate 2 mmol, EDTA 0,2 mmol, pH 6,0
adjusted with sodium hydroxide solution 1 mol) were successfully used for the analysis.
5.9 Arsenic (V) standard stock solution, with an arsenic (V) mass concentration of 1 000 mg/l.
The use of commercial standards of arsenic As (V), with a mass concentration of 1 000 mg/l is
recommended.
5.10 Arsenic (V) standard solution I, with an arsenic (V) mass concentration of 10 mg/l in 2 %
(volume fraction) HNO .
Pipette 1 ml of arsenic standard stock solution (5.9) into a 100 ml volumetric flask. Add 2 ml of nitric acid
(5.2), fill to the mark with water (5.1) and mix well. This solution is stable in a refrigerator at least one
week.
5.11 Arsenic (V) standard solution II, with an arsenic (V) mass concentration of 1 mg/l.

Agilent® is a registered trademark of Agilent Technologies Inc. This information is given for the convenience of
users of this document and does not constitute an endorsement by CEN of the product named. Equivalent products
may be used if they can be shown to lead to the same results.
Pipette 10 ml of arsenic standard solution I (5.10) into a 100 ml volumetric flask, fill to the mark with
water (5.1) and mix well. This solution should be prepared on the same day of use.
5.12 Solution for checking chromatographic separation, containing organic arsenic compounds (e.g.
10 μg/l) monomethylarsenous acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine (AB), as well
as arsenate (e.g. 10 μg/l), arsenite (e.g. 10 μg/l) and chloride (e.g. 100 mg/l).
This solution is recommended to demonstrate satisfactory resolution of individual arsenic species,
possible interferents and to find out how the chromatographic conditions should be optimized (e.g. by
changing the mobile phase concentration or the mobile phase flow rate). The solution shall be prepared
in water (5.1), not in the extraction solution, to check the retention time of the individual arsenic species,
their visual presentation in the chromatogram and how the peaks are separated.
6 Apparatus
6.1 Common laboratory glass (plastic) ware.
Plastic volumetric flasks are recommended for the preparation of the mobile phase and calibration
solutions. All glassware and plastic ware shall be adequately cleaned and stored to avoid any
contamination, including arsenic contamination.
6.2 Laboratory grinder, cap
...