🍎 Determination of formaldehyde and hexamethylenetetramine (HMTA) in food simulants (water, 3 % acetic acid, 15 % ethanol, rectified olive oil) — HMTA is decomposed by heating with acid to formaldehyde, which reacts with chromotropic acid in the presence of sulfuric acid (measurement at 574 nm, 10 mm cell, external standard); confirmation by reaction with pentane-2,4-dione and ammonium acetate (410 nm); approximately (3,0–30) mg formaldehyde/kg simulant, CEN/TS 13130-23

Food chemistry CEN/TS 13130-23

Overview

WHAT THE SPECIFICATION COVERS. We read the text in the iTeh sample of SIST-TS CEN/TS 13130-23:2005 (text of CEN/TS 13130-23:2005, English): from the title page through the contents, foreword, introduction and Clauses 1–3 up to and including 4.3.3. Outside the sample remain the further solutions (from 4.3.4), apparatus (5), samples (6), procedure (7), precision (8), confirmation (9) and the test report.

ACCORDING TO THE TEXT OF CEN/TS 13130-23:2005 (foreword, introduction, Clauses 1–3, 4.1–4.3.3). The document was prepared by CEN/TC 194 “Utensils in contact with food” (secretariat BSI) within the project MAT1-CT92-0006 “Development of Methods of Analysis for Monomers”; CEN approved it on 16.12.2004 for provisional application, with validity initially limited to three years. The foreword links it to Directives 2002/72/EC, 89/109/EEC, 82/711/EEC (with amendments 93/8/EEC and 97/48/EC) and 85/572/EEC, recommends consulting the latest legislation before testing and reading it together with EN 13130-1; in the EN 13130 series Parts 1–8 are European Standards and Parts 9–28 Technical Specifications. Introduction: formaldehyde (PM/Ref. No 17260) and HMTA (PM/Ref. No 18670) are monomers for the manufacture of certain plastics intended to come into contact with food; their residues may migrate into food; since migration of HMTA is limited as formaldehyde, the method determines formaldehyde liberated from HMTA (C6H12N4 + 6 H2O → 6 CH2O + 4 NH3) — both compounds at the same time. The method was pre-validated by a collaborative trial with two laboratories; in trials with three laboratories the chromotropic acid method and the acetyl acetone method gave comparable detection limits, repeatability, recovery and migration, so determination and confirmation are interchangeable. Scope (1): conversion of HMTA to formaldehyde and determination of formaldehyde in the food simulants water, 3 % (w/v) aqueous acetic acid, 15 % (v/v) aqueous ethanol and rectified olive oil; approximate range from 3,0 mg to 30 mg formaldehyde per kilogram of simulant, corresponding to 2,3 mg to 23,3 mg HMTA per kilogram; according to the note the method should also be applicable to other aqueous food simulants and other fatty food simulants (e.g. sunflower oil, corn oil, a mixture of synthetic triglycerides). Normative reference (2): EN 13130-1:2004. Principle (3): HMTA is heated with acid to release formaldehyde; formaldehyde reacts with chromotropic acid in the presence of sulfuric acid, measurement in a spectrophotometer at 574 nm in a cell with an optical path length of 10 mm, quantification with an external standard; confirmation — formaldehyde with pentane-2,4-dione in the presence of ammonium acetate forms 3,5-diacetyl-1,4-dihydrolutidine, absorbance at 410 nm in a 10 mm cell; according to the note the confirmation procedure may be used as the determination, in which case the chromotropic acid method is the confirmation. Reagents (4.1–4.3.3): formaldehyde solution at least 37 % (w/v) stabilised with approximately 10 % methanol; deionised water, glacial acetic acid, absolute ethanol, rectified olive oil, chromotropic acid disodium salt (dihydrate), sulfuric acid with a density of 1,84 g/cm3, acetone, soluble starch, n-pentane; 90 % acetone; stock solution of formaldehyde in water approximately 1,5 mg/ml (approximately 0,8 g of formaldehyde solution in a 200 ml flask), standardised iodometrically (25,0 ml of 0,05 mol iodine solution, 10,0 ml of 1 mol NaOH, 5 min, acidification with 11,0 ml of 1 mol HCl, back-titration of excess iodine with 0,1 mol sodium thiosulfate against starch, blank; 1 ml of 0,1 N iodine corresponds to 1,5 mg formaldehyde), prepared twice and stored in a refrigerator for up to 3 months; stock solution in 90 % acetone approximately 1 mg/ml (approximately 0,3 g of formaldehyde solution in a 100 ml flask).

STATUS (as of 03.10.2026). The PKN search shows no results for the terms “CEN/TS 13130-23” or “13130-23” (03.10.2026). In the iTeh catalogue (read on 03.10.2026) CEN/TS 13130-23:2005 has the status “Published” (stage 60.60, 23.02.2005), and the Slovenian SIST-TS CEN/TS 13130-23:2005 — “Published” (01.04.2005). Overall migration from plastics into aqueous food simulants is described in a separate entry on PN-EN 1186-3.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 03.10.2026). The number 13130-23 appears in 8 records at 7 laboratories: AB 079 (2 records), AB 492, AB 521, AB 537, AB 538, AB 601, AB 910. In the current PCA documents (read on 03.10.2026, issues from 22.04.2026 to 07.08.2026) the number appears in 7 rows of the same laboratories (1 each). The form “CEN/TS 13130-23:2005” (AB 079, AB 492, AB 521 — alongside Commission Regulation (EU) No 10/2011 — and AB 537), “CEN/TS 13130-23: 2005” with a space (AB 538), “CN/TS 13130-23:2005” (AB 601), “Specyfikacja Techniczna CEN/TS 13130-23” after procedure PB-DLS/26 and alongside PN-EN 13130-1 and Commission Regulations (EU) No 10/2011 and No 284/2011 (AB 910, flexible scope “E”). None of these items is suspended. The “Laboratories” tab (term “CEN/TS 13130-23”) shows 5 laboratories: AB 079, AB 492, AB 521, AB 537, AB 538; AB 601 is under the term “CN/TS 13130-23” and AB 910 under “PB-DLS/26” — checked with tab queries on the production server labcoda.pl on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). Object: plastic materials and articles intended to come into contact with food (AB 492, AB 521, AB 538; at AB 079 also “food simulants after migration”), plastics — melamine-formaldehyde moulding compounds intended to come into contact with food (AB 537), melamine-formaldehyde moulding compounds (AB 601), materials and articles intended to come into contact with food (AB 910). Characteristic: migration of formaldehyde into food simulants (AB 492, AB 538; at AB 521 into 3 % acetic acid), migration of formaldehyde (AB 537), specific migration of formaldehyde into the food simulant 3 % acetic acid (AB 601), specific migration of formaldehyde (AB 910), formaldehyde content in the food simulant and from it the specific migration of formaldehyde (calculated) (AB 079). Ranges: (1,5–30) mg/kg of food simulant (AB 079), (1,5–30,0) mg/kg in 3 % acetic acid (AB 492, AB 538) and in 10 % ethanol (AB 492), (1,5–60) mg/kg (AB 537), (3–30) mg/kg (AB 521), (3,0–30,0) mg/kg (AB 601); AB 910 gives no range. Technique: spectrophotometric method (at AB 079 “with 2,4-pentanedione”). The lower limit of 1,5 mg/kg at four laboratories and the upper limit of 60 mg/kg at AB 537 go beyond the approximate range of Clause 1 (3,0–30 mg/kg); 10 % ethanol is not among the four simulants listed in Clause 1 (the note allows other aqueous food simulants).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. With HMTA: without heating with acid HMTA is not converted to formaldehyde (3) — the result then covers only free formaldehyde. With standards: the stock solution must be standardised iodometrically, prepared twice and stored in a refrigerator for at most 3 months (4.3.2). With the food simulant: Clause 1 lists water, 3 % acetic acid, 15 % ethanol and olive oil; other simulants are allowed by the note, but without data in the sample. With the result: the confirmation method is the other of the two reactions — when determining with pentane-2,4-dione, confirmation is with chromotropic acid (3, note). With the range: the approximate range of the method is (3,0–30) mg/kg of simulant (1).

WHAT WE DO NOT GIVE. We did not read the apparatus, sample preparation, course of the determination (HMTA decomposition conditions, volumes, times), precision data, details of the confirmation procedure or the content of the test report. Nor do we give specific migration limits from Regulation (EU) No 10/2011 or migration test conditions (time, temperature) — these are selected according to EN 13130-1 and the legislation.

Method principle

Formaldehyde in the food simulant after a migration test (and also that liberated from hexamethylenetetramine by heating with acid) reacts with chromotropic acid in the presence of sulfuric acid; absorbance is measured at 574 nm in a 10 mm cell and converted with an external standard. The result is confirmed by reaction with pentane-2,4-dione in the presence of ammonium acetate (3,5-diacetyl-1,4-dihydrolutidine, 410 nm); both procedures are interchangeable.

Applications

• Food simulants after migration testing of plastics intended to come into contact with food — water, 3 % acetic acid, 15 % ethanol, rectified olive oil (1)
• Formaldehyde and hexamethylenetetramine (HMTA) — monomers whose migration is limited as formaldehyde (introduction)
• Articles of melamine-formaldehyde moulding compounds and other plastic articles intended to come into contact with food — items in the accreditation scopes of 7 laboratories in PCA

Key parameters

Standard

Standard number

CEN/TS 13130-23:2005

Title (PL)

Materiały i wyroby do kontaktu z żywnością — Substancje w tworzywach sztucznych podlegające ograniczeniom — Część 23: Oznaczanie formaldehydu i heksametylenotetraminy w płynach modelowych

Title (EN)

Materials and articles in contact with foodstuffs — Plastics substances subject to limitation — Part 23: Determination of formaldehyde and hexamethylenetetramine in food simulants

Step-by-step procedure

1. Migration

   Migration test into the food simulant according to EN 13130-1 (conditions from legislation). CEN/TS 13130-23:2005 — no results in the PKN search (03.10.2026).

2. Standards

   Formaldehyde stock solution approximately 1,5 mg/ml standardised iodometrically; two independent solutions.

3. Release from HMTA

   Heating with acid — HMTA is converted to formaldehyde.

4. Determination

   Reaction with chromotropic acid in sulfuric acid, measurement at 574 nm, external standard.

5. Confirmation

   Reaction with pentane-2,4-dione and ammonium acetate, measurement at 410 nm; we do not give the details of Clauses 5–9.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Formaldehyde and concentrated sulfuric acid — work in a fume hood, eye and skin protection
• The specification gives no specific warnings — the user meets the safety requirements of their own country (foreword)

Frequently asked questions