🌱 Water-soluble micronutrients in mineral fertilizers — extraction with water of the forms of boron, cobalt, copper, iron, manganese, molybdenum and zinc and removal of organic compounds from the extract before determination, PN-EN 16962

Physicochemistry PN-EN 16962

Overview

WHAT THE STANDARD COVERS. Scope from the PKN card (Polish version), in full: "This European Standard specifies a procedure for the extraction of water-soluble forms of boron, cobalt, copper, iron, manganese, molybdenum and zinc from mineral fertilizers containing one or more micronutrients and a procedure for the removal of organic compounds from aqueous extracts. The extracts can be analysed according to EN 16963, EN 16965, prEN 17041, prEN 17042, prEN 17043 and CEN/TS 17060." (so on the card — the Polish text contains the English word "and"). The standard therefore has two parts: extraction with water and the removal of organic substances from the extract; the result is given only by the determination standard. The card of PN-EN 16965 adds, from the measurement side, that in most cases small amounts of organic matter do not interfere with FAAS and their removal is not necessary. The card does not give the sample mass, the volume of water, the temperature and time of extraction or the way of removing organic compounds. We did not have the text of the standard (12 pages).

STATUS (state of the cards on 30 September 2026). The card of PN-EN 16962:2018-03 (Polish version) has no "Withdrawn" header — the standard is CURRENT: published 13-11-2019, 12 pages, price group F, Chemistry Sector, KT 156 for Fertilizers, ICS 65.080, "Introduces: EN 16962:2018 [IDT]"; the card has no "Replaces" field. English version: published 06-03-2018, 11 pages, price group F, with a "Scope" field of the same content. The PKN search for "PN-EN 16962" (30 September 2026) shows two items: this standard in the Polish and English versions.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation-scope database, data loaded up to 17 September 2026, read on 30 September 2026). All notations of number 16962: 30 records at 10 laboratories; in the current PCA documents the number appears 29 times — at AB 827 one cell of reference documents covers two rows (zinc, manganese and iron, and copper), which the copy splits into two records. All laboratories write "PN-EN 16962:2018-03"; these are the same laboratories as for PN-EN 16964 and PN-EN 16965 — eight regional chemical-agricultural stations as well as AB 006 and AB 180. The "Laboratories" tab looks for notations that BEGIN with "PN-EN 16962" and will show all 10 laboratories — checked with the tab's query on the production server labcoda.pl on 30 September 2026: 10. Current scopes on the PCA website (read on 30 September 2026, issues from 07.03.2025 to 22.07.2026): all entries are in the issues in force, each of the 44 pairs of range limits from the copy (including 5 at AB 1186, recorded in the copy in the description of the test) appears in the current document and no entry is suspended.

WHAT IS DETERMINED AFTER THIS EXTRACTION. In every entry this standard stands next to a determination standard. Water-soluble copper, manganese and zinc by FAAS according to PN-EN 16965 — all 10 laboratories, iron — 9 (without AB 277), cobalt — AB 180 (FAAS, (0.0010 – 0.156) %) and AB 006 (ICP-OES). Water-soluble boron spectrophotometrically according to PN-EN 17041:2018-07 — 7 laboratories (AB 006, AB 180, AB 312, AB 317, AB 827, AB 921, AB 1186), and above 10.0 % titrimetrically according to PN-EN 17042:2018-07 — AB 006, (10.0 – 20.0) %. ICP-OES according to PN-EN 16963:2018-03 — AB 006: boron, cobalt, copper, iron, manganese, molybdenum and zinc. Entries only for the water-soluble content are held by AB 006, AB 180, AB 277, AB 317 and AB 1186; five laboratories (AB 284, AB 312, AB 333, AB 827, AB 921) enter this standard together with PN-EN 16964 in one entry. Materials: mineral (inorganic) fertilizers — all; AB 006 also fertilizer limes, liming materials and organo-mineral fertilizers, and in the FAAS and ICP-OES entries also organic fertilizers, compost, growing media and products supporting plant cultivation.

ALONGSIDE THIS STANDARD. The total content of micronutrients is obtained by aqua regia extraction according to PN-EN 16964, and the FAAS measurement by PN-EN 16965 (both have separate Knowledge Base entries). Water-soluble macronutrients of fertilizers are covered by other standards of this series, among others the extraction of calcium, magnesium, sodium and sulfur according to PN-EN 15961 (a separate Knowledge Base entry) and water-soluble potassium according to PN-EN 15477 (a separate entry). Chelated micronutrients — PN-EN 13366:2004 with determination according to PN-EN 16965 or PN-EN 16963 — are in the scope of AB 006.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — water-soluble is not total: the same fertilizer gives different figures after extraction with water and with aqua regia, and five laboratories record both standards in one entry — the report must state which extract was measured. Second — organic compounds: the standard provides for their removal from aqueous extracts, while the card of PN-EN 16965 says that with FAAS it is usually not needed; with other techniques and with fertilizers containing organic additives it is worth asking whether the extract was cleaned. Third — the determination standard: the same extract is analysed by FAAS, ICP-OES or the methods for boron, so the report should give both standards — of the extraction and of the determination. Fourth — the material: the scope on the card concerns mineral fertilizers containing micronutrients, while AB 006 also applies this extraction to organic fertilizers, compost and growing media — this goes beyond the scope described on the card.

WHAT WE DO NOT GIVE. We did not have the text of the standard — PKN sells it (12 pages). We do not give the sample mass, the volume of water, the temperature, time and way of shaking, the filtration or the procedure for removing organic compounds.

Method principle

According to the PKN card, the water-soluble forms of boron, cobalt, copper, iron, manganese, molybdenum and zinc are extracted from a mineral fertilizer with water, and — where necessary — organic compounds are removed from the aqueous extract; the elements are determined in the extract according to separate standards: EN 16963 (ICP-OES), EN 16965 (FAAS), EN 17041 and EN 17042 (boron) or CEN/TS 17060. We DO NOT GIVE the conditions of extraction and cleaning — we did not have the text of the standard.

Applications

• Mineral (inorganic) fertilizers containing micronutrients — water-soluble content of boron, cobalt, copper, iron, manganese, molybdenum and zinc — in the scopes of 10 laboratories
• Fertilizer limes, liming materials and organo-mineral fertilizers and — with FAAS and ICP-OES — organic fertilizers, compost and growing media (AB 006)

Key parameters

Standard

Standard number

PN-EN 16962:2018-03 (wersja polska i angielska; EN 16962:2018 IDT)

Title (PL)

Nawozy — Ekstrakcja mikroskładników pokarmowych rozpuszczalnych w wodzie w nawozach i usuwanie związków organicznych z ekstraktów nawozowych

Title (EN)

Fertilizers — Extraction of water soluble micro-nutrients in fertilizers and removal of organic compounds from fertilizer extracts

Step-by-step procedure

1. Status of the document

   PKN card: PN-EN 16962:2018-03 current (state of the card on 30 September 2026).

2. Extraction with water

   From a mineral fertilizer containing micronutrients; we DO NOT GIVE the sample mass, volume, temperature or time.

3. Removal of organic compounds

   From the aqueous extract, when the determination requires it; we DO NOT GIVE the procedure.

4. Determination and result

   According to a separate standard — PN-EN 16965 (FAAS), PN-EN 16963 (ICP-OES), PN-EN 17041 or PN-EN 17042 (boron); result as the water-soluble content, stating both standards.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Standard rules for work in a chemical laboratory; the card does not name the reagents for removing organic compounds — we DO NOT GIVE safety rules for them
• TECHNICAL NOTE: the water-soluble content and the total content (PN-EN 16964) are two different results — the report must name the extraction

Frequently asked questions