🌱 Total and water-soluble magnesium in fertilizers — atomic absorption spectrometry in extracts according to PN-EN 15960 and PN-EN 15961, PN-EN 16197

Physicochemistry PN-EN 16197

Overview

WHAT THE STANDARD COVERS. The scope from the PKN catalogue card, quoted in full: "This European Standard specifies a method for the determination of the magnesium content in fertilizer extracts using atomic absorption spectrometry (AAS). This method is applicable to extracts of EC fertilizers obtained according to EN 15960 and EN 15961 for which a declaration of the total and/or water-soluble magnesium content is required, with the exception of the following fertilizers, according to bibliographic reference [4], Annex I D on secondary nutrients: - type 4 (kieserite); - type 5 (magnesium sulfate) and type 5.1 (magnesium sulfate solution); and with the exception of the following fertilizer listed in bibliographic reference [4], Annex I A.3 on potassium fertilizers: - type 7 (kieserite with potassium sulfate), to which, according to bibliographic reference [4], method 8.8 applies. NOTE Method 8.8 is described in EN 16198 [2]. The method is applicable to all fertilizer extracts containing elements in amounts that may interfere with the complexometric determination of magnesium." (our translation of the Polish card). The card does not expand bibliographic reference [4]; the names of the fertilizer types and annexes follow the layout of Annex I of Regulation (EC) No 2003/2003, repealed with effect from 16 July 2022 (Article 51 of Regulation (EU) 2019/1009) — whether [4] is that regulation we do not know from the card.

STATUS (state of the card on 29 September 2026). The card of PN-EN 16197:2013-05 (Polish version) has no withdrawal note — the standard is CURRENT. Polish version published 19-08-2015, 14 pages, PKN technical committee KT 156 (Fertilizers), ICS 65.080; "Introduces: EN 16197:2012 [IDT]"; there is no "Supersedes" field. The PKN search for "PN-EN 16197" (29 September 2026) shows the Polish and the English version of the 2013-05 edition, neither labelled "Wycofana" (withdrawn).

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17 September 2026, read on 28 September 2026). All records of number 16197: 20 entries at 14 laboratories. Forms: "PN-EN 16197:2013-05" — 11 laboratories, "PN-EN 16197:2013" — AB 277, AB 789 and AB 820. The "Laboratories" tab searches for records BEGINNING with "PN-EN 16197" and will show 13 laboratories — checked with the tab query on the labcoda.pl production server on 29 September 2026: 13; AB 1186 remains outside it (record "PN-EN 15960:2011 PN-EN 16197:2013-05" in one string). Current scopes on the PCA website (read on 29 September 2026, issues from 7 March 2025 to 5 August 2026): all entries stand in the valid issues, every pair of range numbers from the copy appears in the current document and no entry is suspended. At AB 333 the first document of the entry is garbled in the copy (two numbers overlaid); in the PCA scope it reads PN-EN 15960:2011, PN-EN 15961:2017-02 and PN-EN 16197:2013-05.

WHAT THEY DETERMINE. Total magnesium (extract according to PN-EN 15960:2011) and water-soluble magnesium (PN-EN 15961:2017-02) — as separate entries at AB 006, AB 180, AB 284, AB 317, AB 779 and AB 787; as one entry with both extraction standards — AB 277, AB 312, AB 333, AB 820, AB 827 and AB 921; total magnesium only — AB 789 and AB 1186. Technique — everywhere flame atomic absorption spectrometry (FAAS). Ranges as MgO in percent: lower limits from 0.01 (AB 312) and 0.080 (AB 006) through 0.10 (AB 180, AB 317, AB 787 for total magnesium) to 1.0 (AB 284, AB 779) and 2.0 (AB 789); upper limits from 5.00 (AB 317) through 12.0 (AB 277), 15.0 (AB 333, AB 779, AB 787), 20.0 (AB 312, AB 820, AB 921, AB 1186), 22.0 (AB 827), 23.0 (AB 284) and 25.0 (AB 006, AB 789) to 41.5 (AB 180); AB 006, AB 180 and AB 312 also give the range as Mg.

ALONGSIDE THIS STANDARD. For magnesium in mineral fertilizers AB 006 has methods alongside it: by titration according to PN-EN 16198:2013-05 (which contains method 8.8, to which the card refers) and by ICP-OES according to procedure IPL-006 — in both cases together with the extraction standards. Apart from this standard, magnesium in mineral fertilizers is determined by ICP-OES — as one of the elements in an entry "Zawartość pierwiastków" (content of elements) — by AB 1095 (PN-EN 16319+A1:2016-02) and AB 696 (procedure PT-LCAW-13, and for raw materials for fertilizer production PT-LCAW-16). For natural, organic and organo-mineral fertilizers laboratories have in-house procedures (AB 277, AB 312, AB 339, AB 779, AB 787, AB 823, AB 921, AB 930 — FAAS, AB 312 and AB 339 also ICP-OES), and magnesium is also determined by ICP-OES according to standards by AB 700 (compost; PN-EN ISO 11885:2009 with PN-EN 16173 and PN-EN 16174), AB 1249 (compost; PN-EN 16170:2017-02) and AB 213 (compost, biomass, stabilised material; PN-EN 16174 with PN-EN 22036). For agricultural limes — PN-EN 12947:2003 (AB 006, AB 180, AB 339 and AB 1186 — at AB 1186 for magnesium-containing limes), PN-EN 12946:2023-11 (AB 006) and PN-C-87006-11:1990 (magnesium-containing limes). For plant cultivation aids magnesium is determined by ICP-OES by AB 213 (with PN-EN 15960, PN-EN 15961 and PN-EN ISO 11885), AB 1365 (PN-EN ISO 11885 with procedure ILB3b-25) and AB 1748 (PB-80). Calcium in the same extracts — according to PN-EN 16196 (separate entry); water extraction — PN-EN 15961 (separate entry).

WHAT WE DO NOT GIVE. We did not have the text of the standard — PKN sells it (14 pages). We do not give the wavelength, the type of flame, additions to the solutions, the standard solutions, the dilutions, the calculations or the precision.

Method principle

According to the card, magnesium in fertilizer extracts (according to PN-EN 15960 and PN-EN 15961) is determined by atomic absorption spectrometry; the method is also suitable for extracts containing elements that interfere with the complexometric determination, while for kieserite, magnesium sulfate and kieserite with potassium sulfate the card points to method 8.8 of EN 16198. In accreditation scopes — always flame AAS. We DO NOT GIVE the measurement conditions — we did not have the text of the standard.

Applications

• Declared content of total and water-soluble magnesium in mineral fertilizers — in the scopes of 14 laboratories
• Extracts with elements interfering with the complexometric determination of magnesium (card)

Key parameters

Standard

Standard number

PN-EN 16197:2013-05 (wersja polska; wprowadza EN 16197:2012 [IDT])

Title (PL)

Nawozy — Oznaczanie magnezu metodą atomowej spektrometrii absorpcyjnej

Title (EN)

Fertilizers — Determination of magnesium by atomic absorption spectrometry

Step-by-step procedure

1. Extract

   Fertilizer extract according to PN-EN 15960 (total magnesium) or PN-EN 15961 (water-soluble magnesium).

2. Classification of the fertilizer

   For kieserite, magnesium sulfate (and its solution) and kieserite with potassium sulfate — method 8.8 of EN 16198 instead of AAS (card).

3. AAS measurement

   Determination of magnesium by atomic absorption spectrometry — in the scopes by flame AAS; conditions NOT GIVEN.

4. Result

   Magnesium content, in the scopes usually as MgO in percent.

Required equipment and apparatus

Health and safety (OHS)

• Working with a flame spectrometer — safety rules for combustible gases and an extraction hood above the burner
• NOTE ON SUBSTANCE: for kieserite and magnesium sulfate the card points to another method (8.8, EN 16198) — when asking about a test, state the type of fertilizer

Frequently asked questions