FprEN 17768

• Abstract:

  This document specifies the procedure for digestion of different organic and organo-mineral fertilizers with aqua regia to enable a subsequent determination of arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), nickel (Ni), boron (B), cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), mercury (Hg), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), sulfur (S) and sodium (Na)).; This document is applicable to the component materials “by-products”, when used as components of fertilizing products, as well as the fertilizing products blends where a blend is a mix of at least two of the following components: fertilizers, liming materials, soil improvers, growing media, inhibitors, plant biostimulants, and where the following category: organic fertilizers, organo-mineral fertilizers is the highest % in the blend by mass or volume, or in the case of liquid form by dry mass. If the organic fertilizer or the organo-mineral fertilizer is not the highest % in the blend, the European Standard for the highest % of the blend applies. In case a fertilizing product blend is composed of components in equal quantity, the user decides which standard to apply. Variations in analytical methods for fertilizing product blends can lead to differing results as some components or matrix interactions can affect the outcome. Validation procedures have shown that developed standard methods are robust and reliable across diverse product compositions, but possible interferences and unexpected results when analysing fertilizing product blends are possible.; The digests are suitable for analysis using prEN 17770 [11] and prEN 17769 [10].; This document is applicable and validated for several types of matrices as indicated in Annex A.; NOTE 1 Digestates prepared by the procedure given in this document can also be applied for determination of other elements.; NOTE 2 Alternatively, inductively coupled plasma mass spectrometry (ICP-MS) can be used for the measurement if the user proves that the method gives the same results.

• Status: Not Published
• Publication Date: 17-Feb-2027
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 260 - Fertilizers and liming materials
• Drafting Committee: CEN/TC 260/WG 8 - Organic and organo-mineral fertilizers
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 27-Aug-2026
• Due Date: 14-Mar-2027
• Completion Date: 27-Aug-2026
• Directive: Harmonized Standard2019/1009 - 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 and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003 (Text with EEA relevance)
• Mandate: M/564 - Fertilising products in support of Regulation (EU) 2019/1009
• Mandate: M/564 Amd 1 - amending Implementing Decision C(2020) 612 as regards certain harmonised standards and standardisation deliverables, deadlines for their adoption and the duration of the validity of the standardisation request
• Mandate: M/564 Amd 2 - Commission Implementing decision amending Implementing Decision C(2020)612 as regards harmonised standards, the deadlines for the adoption of those standards and the duration of the validity of the standardisation request to the European Committee for Standardisation as regards the EU fertilising products in support of Regulation (EU) 2019/1009 of the European Parliament and of the Council
• Ref Project: oSIST prEN 17768:2026 - Organic and organo-mineral fertilizers - Digestion by aqua regia for subsequent determination of elements

• Revises: CEN/TS 17768:2022 - Organic and organo-mineral fertilizers - Digestion by aqua regia for subsequent determination of elements
• Effective Date: 11-Jun-2025

Overview

FprEN 17768 is a European draft standard developed by CEN for the digestion of organic and organo-mineral fertilizers using aqua regia prior to the determination of key elements. This procedure is designed to ensure accurate, robust, and consistent analysis of elements such as arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), nickel (Ni), boron (B), cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), mercury (Hg), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), sulfur (S), and sodium (Na) in a variety of fertilizer products and blends.

The standard addresses blends where organic or organo-mineral fertilizers constitute the largest component by mass or volume and applies to component materials, including by-products. It ensures harmonized test results vital for regulatory compliance, product labeling, and trade across the European market for fertilizers.

Key Topics

• Aqua Regia Digestion Method: Specifies a robust procedure to digest organic, organo-mineral fertilizers, and their blends while minimizing interferences from matrix components.
• Scope of Application: Includes single products, blends (with two or more fertilizer types and related components), as well as by-products used in fertilizer manufacture.
• Element Determination: The digestates can be used for the quantification of a wide range of macro and micronutrients alongside potential contaminants.
• Sample Preparation: Outlines clear protocols to ensure representative, uncontaminated samples and reduce analysis errors.
• Pre-concentration for Liquids: Provides procedures for evaporating water in liquid samples to overcome detection limits in cases of low analyte concentrations.
• Alternative Analytical Techniques: Allows for the use of inductively coupled plasma mass spectrometry (ICP-MS), provided equivalency is demonstrated.

Applications

The FprEN 17768 standard brings significant value to laboratories, regulatory authorities, and fertilizer producers by:

• Ensuring Regulatory Compliance: Supports adherence to EU Regulation (2019/1009) for fertilizer safety, quality, and contaminant limits.
• Supporting Product Certification: Facilitates accurate determination of regulated elements, contributing to credible product labeling and market acceptance.
• Harmonizing Laboratory Practices: Provides a validated and standardized approach, minimizing variability and uncertainty in elemental analysis across different laboratories and product types.
• Assessing Fertilizer Blends: Covers the increasingly complex formulations seen in today’s fertilizer market, including mixes with soil improvers, plant biostimulants, liming materials, and by-products.
• Integrating with Other Standards: Digestates produced are suitable for further analysis via methods such as prEN 17770 and prEN 17769.

Related Standards

For comprehensive and effective fertilizer analysis, practitioners should reference these related standards:

• prEN 17770 – Determination of total content of specific elements by ICP-AES after aqua regia digestion
• prEN 17769 – Determination of mercury content in organic and organo-mineral fertilizers
• EN 12944-1 / EN 12944-2 – Vocabulary for fertilizers and liming materials
• EN 1482-2 – General sample preparation provisions for fertilizers and related products
• EN 1482-1 / EN 1482-3 – Sampling protocols for solid fertilizers and heaps
• EN 16174, EN ISO 54321 – Aqua regia digestion procedures for soils, biowaste, and sludges
• EN 16317, EN 16319, EN 16320 – Determination of specific contaminants after aqua regia dissolution

By following FprEN 17768, laboratories and regulatory bodies can ensure reliable determination of both nutrient content and heavy metal contaminants, supporting safe and effective fertilizer products in the EU market.

SLOVENSKI STANDARD
01-marec-2026
Organska in organsko-mineralna gnojila - Razklop z zlatotopko za določanje
elementov
Organic and organo-mineral fertilizers - Digestion by aqua regia for subsequent
determination of elements
Organische und organisch-mineralische Düngemittel - Aufschluss durch Königswasser
zur anschließenden Bestimmung der Elemente
Engrais organiques et organo-minéraux - Digestion à l’eau régale pour le dosage
ultérieur des éléments
Ta slovenski standard je istoveten z: prEN 17768
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
prEN 17768
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2026
ICS 65.080 Will supersede CEN/TS 17768:2022
English Version
Organic and organo-mineral fertilizers - Digestion by aqua
regia for subsequent determination of elements
Engrais organiques et organo-minéraux - Digestion à Organische und organisch-mineralische Düngemittel -
l'eau régale pour le dosage ultérieur des éléments Aufschluss durch Königswasser zur anschließenden
Bestimmung der Elemente
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 260.
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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17768:2026 E
worldwide for CEN national Members.

prEN 17768:2026 (E)
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Principle . 6
5 Sampling and sample preparation . 6
6 Reagents . 6
7 Apparatus . 7
8 Procedure. 7
8.1 General . 7
8.2 Sample digestion . 7
8.3 Sample pre-concentration . 8
8.4 Blank test solution . 8
9 Test report . 8
Annex A (informative) Adjustment to different digestion procedures and measurement
apparatuses . 9
Bibliography . 11

prEN 17768:2026 (E)
European foreword
This document (prEN 17768:2026) 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 CEN Enquiry.
This document will supersede CEN/TS 17768:2022.
prEN 17768:2026 includes the following significant technical changes with respect to
CEN/TS 17768:2022:
— The CEN Technical Specification has been adopted as a European Standard;
— Scope (Clause 1) updated including the clarification on fertilizing products blends and the addition of
further elements;
— Normative references (Clause 2) updated by addition of reference to prEN 17773 ;
— Terms and definitions added;
— Sampling and sample preparation (Clause 5) revised;
— Principle described more detailed by adding the number of hours necessary for boiling;
— Apparatus (Clause 7) widened to include information about measures avoiding contamination by
boron;
— Bibliography revised.
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.
prEN 17768:2026 (E)
Introduction
NOTE 1 Regulation (EU) 2019/1009 [1] specifies safety and quality requirements for component materials and
component material categories (CMCs) of fertilizing products available on the EU market.
NOTE 2 By-products within the meaning of Directive 2008/98/EC have been classified as CMC 11, thermal
oxidation materials or derivatives as CMC 13 and recovered high purity materials as CMC 15 in Regulation (EU)
2019/1009 [1].
Aqua regia is applied to digest different matrices for the subsequent determination of many elements.
For example, a multi-matrix standard for aqua regia extraction of soils, sludges and biowaste was
prepared by CEN/TC 444 “Environmental characterization of solid matrices” [2, 3]. A similar procedure
was applied for determination of aqua regia extractable contents of arsenic, mercury, cadmium,
chromium, nickel and lead in fertilizers and liming materials [4, 5, 6], for extraction of micronutrients
from mineral fertilizers [7] etc. CEN/TC 223 “Soil improvers and growing media” published a standard
for a similar procedure for soil improvers and growing media [8]. CEN/TC 455 “Plant Biostimulants”
published a standard for a similar procedure for plant biostimulants [9]. The interlaboratory study (ILS)
for plant biostimulants included also fertilizing product blends of these fertilizing products with some
organic and organo-mineral fertilizers. The ILS proved that the method is also suitable for these fertilizing
product blends.
Wide use of the aqua regia digestion, availability of the instruments and the possibility to merge the
standards for different matrices in future, were the main reasons for also applying this method of
digestion for organic and organo-mineral fertilizers. A simple pre-concentration procedure is a part of
this document to also cover the digestion of liquid samples with low dry matter content in the case that
the measurement method is not sufficiently sensitive. Annex A describes in detail the calculation of the
initial sample mass to be taken for the pre-concentration step to achieve concentrations of the individual
elements above the limit of quantification (LOQ).
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.
prEN 17768:2026 (E)
1 Scope
This document specifies the procedure for digestion of different organic and organo-mineral fertilizers
with aqua regia to enable a subsequent determination of arsenic (As), cadmium (Cd), copper (Cu),
chromium (Cr), lead (Pb), nickel (Ni), boron (B), cobalt (Co), iron (Fe), manganese (Mn), molybdenum
(Mo), zinc (Zn), mercury (Hg), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), sulfur (S)
and sodium (Na)).
This document is applicable to the component materials “by-products”, when used as components of
fertilizing products, as well as the fertilizing products blends where a blend is a mix of at least two of the
following components: fertilizers, liming materials, soil improvers, growing media, inhibitors, plant
biostimulants, and where the following category: organic fertilizers, organo-mineral fertilizers is the
highest % in the blend by mass or volume, or in the case of liquid form by dry mass. If the organic fertilizer
or the organo-mineral fertilizer is not the highest % in the blend, the European Standard for the highest
% of the blend applies. In case a fertilizing product blend is composed of components in equal quantity,
the user decides which standard to apply. Variations in analytical methods for fertilizing product blends
can lead to differing results as some components or matrix interactions can affect the outcome. Validation
procedures have shown that developed standard methods are robust and reliable across diverse product
compositions, but possible interferences and unexpected results when analysing fertilizing product
blends are possible.
1 2
The digests are suitable for analysis using prEN 17770 [11] and prEN 17769 [10].
This document is applicable and validated for several types of matrices as indicated in Annex A.
NOTE 1 Digestates prepared by the procedure given in this document can also be applied for determination of
other elements.
NOTE 2 Alternatively, inductively coupled plasma mass spectrometry (ICP-MS) can be used for the measurement
if the user proves that the method gives the same results.
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.
prEN 17773, Organic and organo- mineral fertilizers — Determination of the dry matter content
EN 12944-1, Fertilizers and liming materials — Vocabulary — Part 1: General terms
EN 12944-2, Fertilizers and liming materials — Vocabulary — Part2: Terms relating to fertilizers
EN 1482-2, Fertilizers, liming materials and inhibitors — Sampling and sample preparation — Part 2:
General sample preparation p
...