🍎 Total phosphorus in meat and meat products — reference gravimetric method: the sample is mineralised with sulphuric and nitric acid, phosphorus is precipitated as quinoline phosphomolybdate, and the precipitate is dried and weighed; PN-ISO 2294:1999 (withdrawn standard)

Food chemistry PN-ISO 2294

Overview

WHAT THE STANDARD COVERS. The "Scope" field of the PKN card, in full: "A method is described consisting in the mineralisation of the sample with sulphuric and nitric acid, precipitation of the phosphorus as quinoline phosphomolybdate, drying and weighing of the precipitate. Clause 10 describes an alternative method of mineralisation" (our translation; no full stop at the end on the card). The description of ISO 2294:1974 in the Standard Norge catalogue says the same. We did not have the text of the standard (6 pages).

STATUS (cards as of 13.10.2026). The card of PN-ISO 2294:1999 (Polish version) bears the heading "Withdrawn": publication 06-08-1999, "Withdrawal date: 25-09-2020", 6 pages, price group C, Food, Agriculture and Forestry Sector, KT 93 Meat, Eggs and their Products, "Adopts: ISO 2294:1974 [IDT]", ICS 67.120.10; there is no "Replaced by" field. The PKN search under "PN-ISO 2294" (12.10.2026) returns only this standard, and under "23776" (13.10.2026) — "No search results". According to the Standard Norge catalogue (13.10.2026), ISO 2294:1974 (ISO/TC 34/SC 6, published on 1 April 1974) has the status "Withdrawn" dated 29 July 2021 with the reference "Revised by: ISO 23776:2021". ISO 23776:2021 "Meat and meat products — Determination of total phosphorous content" (published on 29 July 2021, status "Published") revised ISO 2294:1974 and ISO 13730:1996; according to the description in the catalogue it gives three methods for determining total phosphorus in all kinds of meat and meat products, including poultry: ICP-OES (limit of detection 1.0 mg/kg and limit of quantification 3.0 mg/kg with a 0.5 g test portion and a volume of 50 ml), spectrometric and gravimetric. We did not have the text of ISO 23776.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database from the production server, refreshed on 12.10.2026). Number 2294 appears in 8 records at 7 laboratories; in the current PCA documents (read on 12–13.10.2026; issues from 31.10.2025 — AB 545 — to 23.07.2026 — AB 486) — in 8 rows at the same laboratories (AB 486 — 2 rows); a search of all downloaded PCA documents found no laboratories outside the database copy, no row with the number is set in bold italics, and no pages are repeated in any document. Notations: "PN-ISO 2294:1999" — 6 laboratories (at AB 285 and AB 465 next to PN-A-82060:1999, at AB 465 with the addition "pkt 2.7.2"); "PN ISO 2294:1999" (without a hyphen) — AB 704. The "Laboratories" tab looks for notations BEGINNING with the search term: "PN-ISO 2294" — 6 laboratories, "PN ISO 2294" — 1 — checked with the tab query on the labcoda.pl production server on 13.10.2026; this page searches with "PN-ISO 2294", so the tab shows 6 of the 7 laboratories.

WHAT THE LABORATORIES TEST (database copy and PCA documents). Test object: meat and meat products — all 7; AB 486 in the same entry also fish, seafood and their products, and in a separate one — emulsified vegetable fats. Technique: gravimetric method — all. Characteristic and range: total phosphorus — AB 545 (0.020–0.80 % calculated as P2O5), AB 583 (0.02–0.80 %), AB 585 (0.21–0.78 % P2O5; in the same entry polyphosphates calculated), AB 486 (calculated as P2O5: meat 0.04–8 g/kg, fish and seafood 0.5–10 g/kg, fats 0.5–10.0 g/kg); general phosphorus ("fosfor ogólny") — AB 465 (0.02–1.0 %; added phosphorus calculated), AB 704 (1840–11 700 mg/kg); added phosphorus calculated as P2O5 — AB 285 (0.01–0.90 %).

ALONGSIDE THIS STANDARD. In the entries with this standard: PN-A-82060:1999 (according to the PKN card — determination of general phosphorus and the way of calculating added phosphorus; withdrawn on 07-07-2015) — AB 285, AB 465. Phosphorus in meat and meat products is determined by 35 laboratories in the database copy (entries with phosphorus in the test description or parameters and with meat as the test object, excluding feed, pet food, soils, fertilisers, waste and air): PN-A-82060 is cited by 29, this standard by 7, PN-ISO 13730 (spectrometry, vanadomolybdate complex) by 3 (AB 381, AB 545, AB 601), PN-EN 16943:2017-06 (ICP-OES) by AB 545, in-house procedures among others by AB 485 (DBM/PB-07, gravimetric method, edition 3 of 17.12.2025) and AB 1525 (LB1/PB-12, ICP-MS); nobody cites ISO 23776. AB 545 also has PN-ISO 13730:1999 and PN-EN 16943:2017-06 alongside this standard. The determination according to PN-ISO 13730 and PN-A-82060 is described in separate Knowledge Base entries.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — form and unit of the result: the laboratories report the result in %, g/kg or mg/kg, some calculated as P2O5 (AB 285, AB 486, AB 545, AB 585), some without stating the form; numbers expressed as P and as P2O5 are different, so when comparing results with each other and with a requirement, check the form and the unit. Second — added phosphorus and polyphosphates: the PN-ISO 2294 card speaks only of the determination of total phosphorus; AB 285 and AB 465 also give PN-A-82060 (withdrawn on 07.07.2015) for added phosphorus, whose card describes the way of calculating added phosphorus, and AB 585 gives polyphosphates calculated with no other document in the entry — the way of this calculation cannot be read from the PN-ISO 2294 card. Third — test object: the title of the standard is meat and meat products, while AB 486 also applies it to fish, seafood and emulsified vegetable fats. Fourth — status: PN-ISO 2294 has been withdrawn since 25.09.2020 and ISO 2294 since 29.07.2021; the successor ISO 23776:2021 is not in the PKN catalogue. Fifth — tab: because of the notation without a hyphen (AB 704), the "Laboratories" tab of this page shows 6 of the 7 laboratories.

WHAT WE DO NOT GIVE. We did not have the text of the standard — we do not give the test portion, the amounts and concentrations of the acids, the composition of the quinoline molybdate reagent, the conditions of precipitation, separation and drying of the precipitate, the alternative mineralisation of clause 10, the calculation formula or the precision. We do not give permitted contents of phosphorus or phosphates in meat products — we did not check the regulations.

Method principle

A test portion is mineralised with sulphuric and nitric acid, phosphorus is precipitated from the solution as quinoline phosphomolybdate, and the precipitate is dried and weighed; clause 10 of the standard describes an alternative method of mineralisation (PKN card). WE DO NOT GIVE amounts, conditions or the formula — we did not have the text of the standard.

Applications

• Meat and meat products — total phosphorus by the reference method (withdrawn standard in the current accreditation scopes of 7 laboratories)
• Fish, seafood and their products, emulsified vegetable fats — only in the scope of AB 486

Key parameters

Standard

Standard number

PN-ISO 2294:1999

Title (PL)

Mięso i przetwory mięsne — Oznaczanie zawartości fosforu całkowitego (Metoda odwoławcza)

Title (EN)

Meat and meat products — Determination of total phosphorus content (Reference method)

Step-by-step procedure

1. Mineralisation

   A test portion is mineralised with sulphuric and nitric acid; alternative — clause 10 (PKN card). PN-ISO 2294:1999 withdrawn on 25-09-2020 (card as of 13.10.2026).

2. Precipitation

   Phosphorus is precipitated as quinoline phosphomolybdate (PKN card).

3. Drying and weighing

   The precipitate is dried and weighed (PKN card); WE DO NOT GIVE temperatures or times.

4. Result

   Total phosphorus from the mass of the precipitate; in the report the form (P or P2O5) and the unit — in accreditation scopes %, g/kg or mg/kg.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Sulphuric acid and nitric acid — safety rules of a chemical laboratory and the safety data sheets of the substances
• SUBJECT-MATTER NOTE: a result as P and as P2O5 are different numbers — check the form and the unit when comparing

Frequently asked questions