oSIST prEN 18258:2025
(Main)Soil improvers and growing media - Determination of the mercury content
Soil improvers and growing media - Determination of the mercury content
Soil improvers and growing media - Determination of mercury in aqua regia soil extracts with cold-vapour atomic spectrometry or cold-vapour atomic fluorescence spectrometry
Bodenverbesserungsmittel und Kultursubstrate - Bestimmung von Quecksilber in Königswasser-Extrakten
Dieses Dokument legt ein Verfahren zur Bestimmung von Quecksilber in nach prEN13650:2025 hergestellten Königswasseraufschlüssen von Bodenverbesserungsmitteln und Kultursubstraten mittels eines Systems der (Kalt-)Dampftechnik, gekoppelt mit einem Atomabsorptionsspektrometer, oder mittels eines Verfahrens, das auf thermischer Zersetzung, Amalgamierung und Atomabsorptionsspektrometrie beruht, fest. Letztere Technik ist auch für die direkte Analyse von festen Proben geeignet.
ANMERKUNG1 Auch die Anwendung anderer, in AnhangA beschriebener, geeigneter Verfahren der Quecksilberbe
stimmung ist möglich, sofern die Anwender nachweisen, dass das Verfahren zu gleichen Ergebnissen führt wie die in diesem Dokument beschriebenen Verfahren.
ANMERKUNG2 Unter besonderen Umständen, in denen Quecksilber in Silikaten oder anderen Matrices (z.B. Phosphaten), die sich nicht thermisch zersetzen, gebunden ist, ist es unerlässlich, die direkte Analyse der festen Probe unter Anwendung des Königswasseraufschlusses nach prEN13650:2025 mit anschließender Analyse mittels dieses Verfahrens zu validieren (siehe5.2).
Amendements du sol et supports de culture - Détermination de la teneur en mercure
Le présent document spécifie une méthode de dosage du mercure dans les digestats à l’eau régale d’amendements du sol et de supports de culture, préparés conformément au prEN 13650:2025, avec un appareil de génération de vapeur (à froid) couplé à un spectrophotomètre d’absorption atomique ou de décomposition thermique, d’amalgamation et de spectrophotométrie d’absorption atomique. Avec cette dernière technique, l’analyse directe convient également aux échantillons solides.
NOTE 1 Il est aussi possible d’utiliser d’autres méthodes adaptées pour le dosage du mercure décrites dans l’Annexe A, si l’utilisateur prouve que la méthode conduit aux mêmes résultats que les méthodes décrites dans le présent document.
NOTE 2 Dans des circonstances uniques où le mercure est lié dans des silicates ou d’autres matrices (par exemple des phosphates) qui ne se décomposent pas thermiquement, il est essentiel de valider l’analyse directe du solide en utilisant la digestion à l’eau régale conformément au prEN 13650:2025, suivie d’une analyse avec cette méthode (voir 5.2).
Izboljševalci tal in rastni substrati - Določanje živega srebra
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2025
Izboljševalci tal in rastni substrati - Določanje živega srebra
Soil improvers and growing media - Determination of the mercury content
Bodenverbesserungsmittel und Kultursubstrate - Bestimmung von Quecksilber in
Königswasser-Extrakten
Amendements du sol et supports de culture - Détermination de la teneur en mercure
Ta slovenski standard je istoveten z: prEN 18258
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
mercury content
Amendements du sol et supports de culture - Bodenverbesserungsmittel und Kultursubstrate -
Détermination de la teneur en mercure Bestimmung von Quecksilber in Königswasser-
Extrakten
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 18258:2025 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 . 5
4.1 Vapour generation atomic absorption spectrophotometry (VG-AAS) . 5
4.2 Thermal decomposition, amalgamation and atomic absorption spectrophotometry (AAS)
(TD-AAS). 5
5 Interferences . 6
5.1 Vapour generation atomic absorption spectrophotometry (VG-AAS) . 6
5.2 Thermal decomposition, amalgamation and atomic absorption spectrophotometry (AAS)
(TD-AAS). 6
6 Reagents . 6
7 Apparatus . 7
8 Sampling . 7
9 Procedure . 8
9.1 Preparation of the test and blank solutions . 8
9.2 Preparation of the calibration solutions . 8
9.3 Measurement . 8
9.3.1 Instrument conditions . 8
9.3.2 Matrix effects . 8
9.3.3 Spiking . 9
9.3.4 Measurement by VG-AAS . 9
9.3.5 Measurement by TD-AAS. 9
10 Calculation and expression of the results . 10
10.1 Content of mercury. 10
11 Test report . 11
12 Validation of the method . 11
12.1 Validation in accordance with ISO 5725-2. 11
12.2 Performance characteristics. 11
Annex A (informative) Methods for mercury determination . 12
Annex B (informative) Performance characteristics of the method . 14
Bibliography . 16
European foreword
This document (prEN 18258:2025) 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 concerns the analytical measurement step for the determination of mercury in soil
improvers and growing media after digestion by aqua regia according to prEN 13650:2025or directly by
thermal decomposition, amalgamation and atomic absorption spectrophotometry (AAS). The document
covers cold vapour generation followed by mercury determination using atomic absorption
spectrophotometry (AAS). Different cold vapour generation techniques can be used (flow injection,
segmented flow, batch). The document also includes a direct method based on thermal decomposition,
amalgamation and AAS which is widely used in many analytical laboratories. It is also possible to use
other suitable methods of mercury determination described in Annex A, if users prove that the methods
give the same results as the methods described in this document.
1 Scope
This document specifies a method for determination of mercury in aqua regia digests of soil improvers
and growing media, prepared according to prEN 13650:2025, using (cold) vapour generation apparatus
coupled to an atomic absorption spectrophotometer or thermal decomposition, amalgamation and
atomic absorption spectrophotometry. With the latter technique, direct analysis is also suitable for solid
samples.
NOTE 1 It is also possible to use other suitable methods for the determination of mercury described in Annex A
if users prove that the method gives the same results as the methods described in this document.
NOTE 2 In unique circumstances where mercury is bound in silicates or other matrices (e.g. phosphates) that do
not thermally decompose, it is essential to validate direct analysis of the solid using the aqua regia digestion
according to prEN 13650:2025, followed by analysis with this method (see Clause 5.2).
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
prEN 13650:2025, Soil improvers and growing media — Digestion by aqua regia for subsequent
determination of elements
3 Terms and definitions
For the purposes of this document the terms and definitions given in CEN/TS 17732:2022 apply.
4 Principle
4.1 Vapour generation atomic absorption spectrophotometry (VG-AAS)
Mono- and divalent mercury is reduced to the elemental form by tin(II) chloride or sodium borohydride
in an acid medium. Elemental mercury is stripped off from the solution and determined in the form of an
atomic gas by an atomic absorption spectrophotometer.
4.2 Thermal decomposition, amalgamation and atomic absorption spectrophotometry
(AAS) (TD-AAS)
The sample is thermally decomposed in an oxygen rich environment. The decomposition products are
carried to an amalgamator that selectively traps mercury. After the system is flushed with oxygen to
remove any remaining gases or decomposition products, the amalgamator is rapidly heated, releasing
mercury vapour. Flowing oxygen carries the mercury vapour through absorbance cells positioned in the
light path of a single wavelength atomic absorption spectrophotometer. Absorbance is measured at
253,7 nm as a function of mercury concentration.
5 Interferences
5.1 Vapour generation atomic absorption spectrophotometry (VG-AAS)
The matrix of the solution analysed is dominated by the acids used in the digestion step. Tin(II) chloride
as a reduction substance is recommended, because sodium borohydride reduces many elements
commonly found in organic fertilizers and organo-mineral fertilizers digests to the elemental state, which
may cause matrix problems under particular circumstances. However, it is still possible to use sodium
borohydride as a reduction agent. The interferences due to the presence of other elements in the matrix
depend on its concentrations. Copper, manganese and nickel exceeding a concentration of 500 mg/l can
cause a negative bias.
5.2 Thermal decomposition, amalgamation and atomic absorption spectrophotometry
(AAS) (TD-AAS)
Instruments with an amalgamation technique are very often used for a direct determination of mercury
in samples without a digestion step. Nevertheless, some solid samples (e.g. samples with a very high
silicates or phosphate content) might not be fully thermally decomposed and therefore in this case or if
an unknown sample is analysed, the analysis of aqua regia digests is preferable. For organic fertilizers
and organo-mineral fertilizers usually no difference is observed between the direct determination of
mercury and the determination of mercury after digestion in aqua regia.
6 Reagents
The concentration of mercury in the reagents and in water shall be negligible compared to the lowest
concentration of mercury to be determined.
6.1 Water with a specific conductivity not higher than 0,2 mS/m at 25 °C.
6.2 Carrier gas.
Argon or nitrogen for VG-AAS and VG-ICP-OES, oxygen for TD-AAS, purity according to the
recommendation of the manufacturer.
6.3 Hydrochloric acid, c(HCl) ≈ 12 mol/l; 37 % volume fraction; mass concentration ρ approximately
1,18 g/ml.
6.4 Nitric acid, c(HNO ) ≈ 16 mol/l; not less than 65 % volume fraction; ρ approximately 1,42 g/ml.
6.5 Mixed acid solution, 0,8 mol/l nitric acid and 1,8 mol/l hydrochloric acid.
M
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