CEN/TC 260

Date: 2025-10

prEN 17766:2025

Secretariat: CEN/TC 260

Organic and organo-mineral fertilizers — Extraction by water for subsequent determination of elements

Organische und organisch-mineralische Düngemittel - Extraktion durch Wasser zur anschließenden Bestimmung der Elemente

Engrais organiques et organo-minéraux - Extraction à l’eau pour le dosage ultérieur des éléments

CCMC will prepare and attach the official title page.

Contents Page

European foreword 3

Introduction 4

1 Scope 5

2 Normative references 5

3 Terms and definitions 5

4 Principle 5

5 Sampling and sample preparation 6

6 Reagents 6

7 Apparatus 6

8 Procedure 6

9 Test Report 7

Bibliography 8

European foreword

This document (prEN 17766:2025) 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 17766:2022.

Compared to the previous edition, prEN 17766:2025 includes the following significant technical changes:

— the CEN Technical Specification has been adopted as a European Standard;

— Introduction added;

— Scope (Clause 1) updated including the clarification on fertilizing product blends and the analytical method to be used;

— Reagents (Clause 6) updated with the addition of nitric acid;

— Apparatus (Clause 7) updated specifying more details and adding a remark regarding the quality of the laboratory glassware;

— Procedure (Clause 8) updated describing more details on the procedure and making specific adaptations to procedural changes;

— Bibliography updated.

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

Water is applied to extract available fraction of micronutrients from different matrices for their subsequent determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). A similar procedure was applied for extraction of micronutrients from mineral fertilizers [2].

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.

This document specifies the procedure for extraction of different organic and organo-mineral fertilizers with water to enable a subsequent determination of boron (B), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), phosphorous (P) and zinc (Zn).

NOTE Extracts prepared by the procedure given in this document can also be applied for determination of other elements.

This document is applicable to 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 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 — Part2: Terms relating to fertilizers

EN 1482‑2, Fertilizers, liming materials and inhibitors — Sampling and sample preparation — Part 2: General sample preparation provisions

For the purposes of this document, the terms and definitions given in EN 12944‑1 and EN 12944‑2 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/

The elements are extracted from samples by shaking with water under the specified conditions.

The extracts are analysed according to prEN 17774.

Sampling is not part of the method specified in this document. Recommended sampling methods are given in EN 1482‑1 [3] and in EN 1482‑3 [4].

It is important that the laboratory receives a sample that is representative of both the product under consideration and the given analysis. The sample should not have been damaged or changed during transport or storage.

Sample preparation shall be carried out in accordance with EN 1482‑2.

6.1 Water, with a specific conductivity not higher than 0,2 mS/m at 25 °C, free from the elements to be determined.

6.2 Nitric acid, c(HNO₃) ≈ 14,3 mol/l, ρ ≈ 1,4 g/ml.

7.1 Shaker, rotary or horizontal eccentric shaker.

7.2 Extraction vessels, capacity 400 ml to 6 500 ml.

7.3 Filter paper, ash-free and of recognized and tested quality.

7.4 Common laboratory glassware

All glassware and plastic ware shall be adequately cleaned and stored to avoid any contamination. If boron content is to be determined, it is necessary to minimize the contact of all solutions with borosilicate glassware. Suitable plastic or silica ware is needed especially for the extraction step. Glass volumetric flasks may be used for making up to volume but not for storage of digests and solutions.

Weigh (5 ± 0,005) g of the prepared sample, transfer the sample quantitatively to a 500 ml extraction vessel (7.2) and add (250 ± 0,2) ml of water (6.1) at (20 ± 2) °C.

Smaller amounts of sample (between 1 g and 5 g) can be used as well, the proportion between sample mass and final volume has to stay constant (1: 100).

Close the vessel tightly and shake vigorously by hand to disperse the sample. Then place the vessel on the shaker (7.1) and shake for 60 min. The intensity of shaking shall be adjusted to prevent any settling of the sample during the extraction. The temperature of the extraction solution shall be kept at (20 ± 2) °C during the whole extraction time. Filter the extract if necessary immediately after the extraction into a plastic vessel. Use filter paper of recognized and tested quality (7.3) and discard the first portion of the filtrate (approximately 20 ml).

Prepare a blank test solution following the same procedure as for samples.

The extracts should be measured according to prEN 17774 on the same day. If necessary, the extracts can be kept in tightly closed vessels at (4 ± 3) °C for a maximum of two days before determination without additional conservation. If stored longer, they shall acidify using a small amount of nitric acid (6.2).

The test report is part of the test report of the determination method and shall contain at least the following information:

1. all information necessary for the complete identification of the sample;
2. test method used with reference to this document including its year of publication;
3. date of sampling and sampling procedure (if known);
4. date when the extraction was finished;
5. all operating details not specified in this document, or regarded as optional, together with details of any incidents occurred when performing the method, which might have influenced the test result(s).

Bibliography

[1] 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

[2] EN 16962, Fertilizers — Extraction of water soluble micro-nutrients in fertilizers and removal of organic compounds from fertilizer extracts

[3] EN 1482‑1, Fertilizers, liming materials and inhibitors — Sampling and sample preparation — Part 1: General sampling provisions

[4] EN 1482‑3, Fertilizers, liming materials and inhibitors — Sampling and sample preparation – Part 3: Sampling of static heaps

[5] prEN 17774,^[1] Organic and organo-mineral fertilizers — Determination of the content of specific elements by ICP-AES after extraction by water and weak solvents

1. Under preparation. ↑