🧵 Determination of free formaldehyde and formaldehyde partly released by hydrolysis in textiles of any form by the water extraction method — approx. 1 g (up to 2,5 g) of cut sample in 100 ml of water, 60 min at 40 °C, reaction of the filtrate with acetylacetone (Nash) reagent, absorbance at 412 nm against a calibration curve from at least five standard solutions, range 16–3500 mg/kg, below 16 mg/kg “not detectable”, PN-EN ISO 14184-1

Materials and NDT PN-EN ISO 14184-1

Overview

WHAT THE STANDARD COVERS. Scope from the PKN catalogue card of PN-EN ISO 14184-1:2011 (English version; scope in Polish on the card), in full (our translation): “This part of EN ISO 14184 describes a method for the quantitative determination of free formaldehyde and formaldehyde partly extractable by hydrolysis by a water extraction method. The method can be applied to testing samples of textile products in any form. The procedure is intended for determining free and hydrolysed formaldehyde in textile products in amounts from 16 mg/kg to 3 500 mg/kg when determined by this method. The lower limit is 16 mg/kg. Below this limit the result is reported as "not detected". A method for determining released formaldehyde is given in EN ISO 14184-2”. We read the text of the standard in the preview of ISO 14184-1:2011 from the cover to the end of Clause 10 (test report); we do not have Annex A (normative — standardization of the formaldehyde stock solution) or Annex B (informative — accuracy of the method).

ACCORDING TO THE TEXT OF ISO 14184-1:2011 (foreword, Clauses 1–10). The standard was prepared by ISO/TC 38 (textiles); the second edition is a minor revision of ISO 14184-1:1998; Part 2 of the series covers released formaldehyde (vapour absorption method). General warning: the standard calls for substances and procedures that may be injurious to health without adequate precautions. References: ISO 139:2005, ISO 3696:1987, ISO 4793:1980. Principle (3): formaldehyde is extracted with water at 40 °C and its amount determined colorimetrically. Reagents (4): distilled or grade 3 water; acetylacetone (Nash) reagent — 150 g of ammonium acetate in approx. 800 ml of water, 3 ml of glacial acetic acid and 2 ml of acetylacetone, to 1000 ml, in a brown bottle; it darkens slightly during the first 12 h, so it is held for 12 h before use; usable for at least 6 weeks, and running a calibration curve weekly is good practice; formaldehyde solution approx. 37 %; dimedone 1 g in 100 ml of ethanol, prepared immediately before use. Apparatus (5): flasks, pipettes (automatic pipettes of the same accuracy allowed), 10 and 50 ml burettes; spectrophotometer reading absorbance to at least three decimal places at 412 nm; water bath (40 ± 2) °C; glass filters with pores of 40–100 µm (P100 according to ISO 4793); balance 0,2 mg. Calibration (6): stock solution approx. 1500 mg/l (3,8 ml of 37 % formaldehyde per 1 l), standardized according to Annex A, keeps up to 4 weeks; the concentration in the fabric is 100 times the concentration in solution (1 g of sample, 100 ml of water); solution S2 of 75 mg/l (10 ml of stock to 200 ml); at least five of eight calibration solutions: 1, 2, 5, 10, 15, 20, 30 or 40 ml of S2 to 500 ml, i.e. 0,15; 0,30; 0,75; 1,50; 2,25; 3,00; 4,50; 6,00 µg/ml, corresponding to 15; 30; 75; 150; 225; 300; 450; 600 mg/kg in the fabric; linear regression y = a + bx; above 500 mg/kg the sample solution is diluted. Specimen (7): it is NOT conditioned — predrying and humidity may change the formaldehyde content; before testing it is stored in a container (note: e.g. in a polyethylene bag wrapped in aluminium foil — formaldehyde may diffuse through the pores of the bag, and catalysts in an unwashed finished fabric may react with the foil on direct contact). Two specimens are cut into small pieces and approx. 1 g is weighed to 10 mg (up to 2,5 g at low content); each is covered with 100 ml of water in a 250 ml flask, stoppered and kept in a water bath at (40 ± 2) °C for (60 ± 5) min, shaking at least every 5 min, then filtered; in case of dispute, a conditioned parallel specimen according to ISO 139 and a mass correction coefficient are used. Determination (8): 5 ml of filtrate and 5 ml of each standard solution with 5 ml of acetylacetone reagent; (30 ± 5) min at 40 °C and (30 ± 5) min at ambient temperature; reagent blank — 5 ml of reagent and 5 ml of water; absorbance in a 10 mm cell at 412 nm against water; at expected or calculated content above 500 mg/kg — dilution of the extract; specimen blank (discoloration, impurities) — 5 ml of solution and 5 ml of water instead of reagent; at least two parallel tests. Caution: the yellow colour fades in direct sunlight — if reading is delayed (e.g. 1 h), the tubes are protected; otherwise the colour is stable at least overnight. If in doubt whether the absorption is due to formaldehyde or e.g. a dye, a confirmation test with dimedone is made (8.6–8.7): 5 ml of solution + 1 ml of dimedone, (10 ± 1) min at 40 °C, then 5 ml of reagent, (30 ± 5) min at 40 °C and (30 ± 5) min at room temperature — the formaldehyde absorbance at 412 nm disappears. Calculation (9): A = As − Ab − (Ad) (Ad only for discoloration or contamination), concentration from the curve, wF = ρ × 100 / m (ρ in mg/l, m in g), to 1 mg/kg; mean of two specimens; below 16 mg/kg — “not detectable”. Test report (10): among others date received, storage and test date, packaging of the sample, specimen masses and correction coefficient, range of the calibration curve.

STATUS (PKN catalogue cards as of 02.10.2026). The card of PN-EN ISO 14184-1:2011 (English version, published 18-10-2011, 11 pages, price group F) has no “Withdrawn” header: Consumer Products Sector, KT 26 Textile Products, ICS 59.080.01, “Introduces: EN ISO 14184-1:2011 [IDT], ISO 14184-1:2011 [IDT]”, “Replaces: PN-EN ISO 14184-1:2001 – Polish version”. The PKN search for “PN-EN ISO 14184-1” (02.10.2026) shows only these two editions.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 02.10.2026). The number 14184-1 appears in 7 records at 7 laboratories: AB 062, AB 077, AB 079, AB 403, AB 910, AB 1401, AB 1573. In the current scopes on the PCA website (read 02.10.2026, issues from 08.01.2025 to 11.08.2026) six give “PN-EN ISO 14184-1:2011”, and AB 910 — the number without a year next to JIS L 1041, PN-EN 71-9 and PN-EN 12586. The “Laboratories” tab searches for entries STARTING WITH “PN-EN ISO 14184-1” and shows all 7 laboratories — checked with the tab query on the production server labcoda.pl on 02.10.2026.

WHAT THE LABORATORIES TEST (PCA entries). “Formaldehyde content”, spectrophotometric method: textiles and leather, fabrics, yarn, clothing and finished products — from 16,0 to 300,0 mg/kg (AB 062); textiles, artificial leather, fabrics, yarn — from 15 to 600 mg/kg (AB 077); toys and toy materials of textiles, textiles — from 16 to 3500 mg/kg (AB 079); textile products, “free and hydrolysed formaldehyde” — from 16 to 600 mg/kg (AB 403); textile products, leather and leather products — from 10 to 2500 mg/kg (AB 1401); flat textile products (woven fabrics, knitted fabrics, yarn, nonwovens, coated products, clothing) — from 16 to 600 mg/kg (AB 1573); toys, textile products, childcare articles, soother holders — no range, in a line next to Directive 2009/48/EC on the safety of toys (AB 910).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Specimen: conditioning before the test may change the formaldehyde content — the standard forbids it; in a polyethylene bag alone formaldehyde may diffuse through the pores, which is why the note to Clause 7 gives a bag wrapped in aluminium foil. Extraction: the standard sets (60 ± 5) min at (40 ± 2) °C, shaking at least every 5 min and complete wetting of the specimen — what is determined is free formaldehyde and the formaldehyde passing into the water by hydrolysis under these conditions, so the result depends on keeping them. Measurement: the Nash reagent still darkens during the first 12 h after preparation; a coloured extract without the specimen blank (Ad) inflates the result, and a dye absorbing at 412 nm can be mistaken for formaldehyde — the dimedone test decides; exposing the tubes to the sun lowers the reading. Calculation: the result in the fabric is 100 times the concentration in solution only for 1 g and 100 ml — with 2,5 g or a dilution the actual mass and factor must be used. Range: the standard sets a lower limit of 16 mg/kg and requires lower results to be reported as “not detectable”, while two laboratories give a range starting lower — AB 1401 from 10 mg/kg and AB 077 from 15 mg/kg. Test item: the standard speaks of textile products, while AB 062 and AB 1401 also apply it to leather and leather products. Part of the standard: RELEASED formaldehyde (vapour absorption) is Part 2 — a separate method with a different principle.

WHAT WE DO NOT STATE. We do not have Annex A (how the formaldehyde stock solution is standardized) or Annex B (data on the accuracy of the method) — we therefore give neither the standardization procedure nor any precision figure.

Method principle

A cut textile specimen is extracted with water at 40 °C for 60 min; formaldehyde in the filtrate reacts with acetylacetone and ammonium acetate (Nash reagent) giving a yellow compound whose absorbance at 412 nm is compared with a calibration curve; result in mg/kg of fabric (16–3500 mg/kg).

Applications

• Textile products: woven and knitted fabrics, yarn, nonwovens, clothing — 7 laboratories in PCA scopes
• Toys and toy materials of textiles, childcare articles
• Checking compliance of products with formaldehyde requirements (result in mg/kg, “not detectable” below 16 mg/kg)

Key parameters

Standard

Standard number

PN-EN ISO 14184-1:2011 (wersja angielska; EN ISO 14184-1:2011 IDT, ISO 14184-1:2011 IDT)

Title (PL)

Tekstylia — Oznaczanie formaldehydu — Część 1: Formaldehyd wolny i zhydrolizowany (metoda ekstrakcji wodnej)

Title (EN)

Textiles — Determination of formaldehyde — Part 1: Free and hydrolysed formaldehyde (water extraction method)

Step-by-step procedure

1. Specimen

   Do not condition; store in a container (e.g. PE bag wrapped in aluminium foil). Cut two specimens, weigh approx. 1 g (± 10 mg). PN-EN ISO 14184-1:2011 current (PKN cards as of 02.10.2026).

2. Extraction

   Specimen + 100 ml water in a 250 ml stoppered flask; (60 ± 5) min in a (40 ± 2) °C bath, shake at least every 5 min; filter through a P100 filter.

3. Calibration

   At least five solutions from S2 (0,15–6,00 µg/ml) subjected to the same reaction; regression y = a + bx; check the curve weekly.

4. Reaction and measurement

   5 ml filtrate + 5 ml Nash reagent; (30 ± 5) min at 40 °C and (30 ± 5) min at ambient temperature; absorbance at 412 nm against water; reagent blank and — for coloured extracts — specimen blank; protect from sunlight.

5. Result

   A = As − Ab − (Ad); wF = ρ × 100 / m in mg/kg, mean of two specimens; below 16 mg/kg — “not detectable”; if in doubt, dimedone test.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The standard warns that it calls for substances and procedures injurious to health without adequate precautions; 37 % formaldehyde — work in a fume cupboard
• The yellow colour fades in direct sunlight — protect the tubes if reading is delayed (caution in 8.5)
• TECHNICAL NOTE: the specimen is not conditioned; lower limit 16 mg/kg, lower results as “not detectable”; released formaldehyde — Part 2 of the standard

Frequently asked questions