🌿 Determination of formaldehyde and other carbonyl compounds (aldehydes and ketones) in indoor air and test chamber air — air drawn through a cartridge of silica gel coated with 2,4-dinitrophenylhydrazine (DNPH), elution of the hydrazones and HPLC analysis with UV or DAD detection at 360 nm; range approx. 1 µg/m³–1 mg/m³, time-weighted average sample (1–24 h or 5–60 min), flow up to 1.5 l/min; 13 carbonyl compounds listed in the scope; ISO 16000-3:2022

Environment ISO 16000-3

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of ISO 16000-3:2022 (third edition, 2022-09, English text): contents, foreword, introduction, Clauses 1–6 and Clause 7 up to 7.3.1 — the sample ends on page 6. We do not read the rest of the apparatus, reagents (8), preparation of reagents and cartridges (9), procedure (10), calculations (11), quality criteria (12), precision and uncertainty (13), test report (14) or Annexes A (melting points of DNPH derivatives) and B (precision and uncertainty); we know the titles from the contents.

ACCORDING TO THE TEXT OF ISO 16000-3:2022. The standard was prepared by ISO/TC 146 “Air quality”, Subcommittee SC 6 “Indoor air”. The third edition replaces the second (ISO 16000-3:2011); main change: clarification of the suitability of the method for acrolein measurements. Introduction: the document is used to characterize indoor air following the sampling strategy of ISO 16000-2; the method has been tested for 14 aldehydes and ketones; the major indoor sources of formaldehyde are emissions from particle board and wall insulation; sampling is based on US EPA method TO-11A. Scope (1): determination of formaldehyde (HCHO) and other carbonyl compounds in air; the method is specific to formaldehyde, and with modification at least 12 other carbonyl compounds — aromatic as well as saturated and unsaturated aliphatic — can be detected and quantified; concentration range approx. 1 µg/m³ to 1 mg/m³; time-weighted average (TWA) sample, long-term (1–24 h) or short-term (5–60 min) sampling; the method is not suitable for longer-chained or unsaturated carbonyl compounds. List of compounds: acetaldehyde, acetone, benzaldehyde, butyraldehyde, capronaldehyde, 2,5-dimethylbenzaldehyde, formaldehyde, isovaleraldehyde, propionaldehyde, m-, o- and p-tolualdehyde, valeraldehyde. Normative reference (2): ISO/IEC 17025. Principle (4): air is drawn through a cartridge of silica gel coated with DNPH; the carbonyl group reacts with DNPH in the presence of acid to form stable derivatives (2,4-dinitrophenylhydrazones), which are analysed by HPLC with UV or diode array detection; cartridges can be prepared by the user, but pre-coated commercial ones are recommended — more uniform and with lower blanks, provided they are shown to meet the criteria of the standard. Limitations (5.1): flow validated up to 1.5 l/min; user-prepared cartridges (gel 55–105 µm) have a high pressure drop (> 8 kPa at 1.0 l/min) and are generally not compatible with personal pumps; interferences come from unresolved isomeric aldehydes and ketones and from compounds with the same retention time and absorbance at 360 nm as the formaldehyde derivative; DNPH is often contaminated with formaldehyde — it is purified by multiple recrystallizations from acetonitrile (40–60 °C), and the contamination should be below 0.15 µg per cartridge; direct sunlight produces artefacts; acrolein and crotonaldehyde cannot be accurately quantified (multiple derivative peaks, unstable ratios); NO2 reacts with DNPH, and its derivative may have a retention time close to that of the formaldehyde derivative (e.g. gas cooking stoves). Ozone (5.2): biases results low by reacting with DNPH and the hydrazones in the cartridge, even at concentrations typical of clean ambient air (formaldehyde 2 µg/m³, ozone 80 µg/m³); its presence is revealed by new peaks before the formaldehyde hydrazone; the remedy is a denuder (1 m of copper tubing, inside diameter 0.46 cm, with saturated potassium iodide, capacity approx. 200 µg/m³·h) or a cartridge with 300–500 mg of potassium iodide in front of the DNPH cartridge. Safety (6): dry DNPH is explosive, toxic (rat LD50 654 mg/kg) and mutagenic in some tests; perchloric acid above 160 °C dehydrates and may explode on contact with oxidizable materials. Apparatus (7): cartridge with at least 350 mg of gel and at least 0.29 % (m/m) DNPH, bed diameter to length ratio not above 1:1, formaldehyde capacity at least 75 µg and collection efficiency at least 95 % at 1.5 l/min; pump 0.1–1.5 l/min; flow controller 0.50–1.20 l/min; flow calibrator accurate to 0.1 %; non-absorbent gloves; HPLC system with C-18 column (e.g. 25 cm × 4.6 mm, 5 µm), loop e.g. 25 µl and UV or DAD detector at 360 nm; the formaldehyde derivative is determined isocratically, with a blank cartridge, by comparing retention times and peak heights or areas with standard solutions.

STATUS (as of 03.10.2026). The PKN search engine (query “16000-3”, 03.10.2026) shows no standard introducing ISO 16000-3 — the results concern other documents (e.g. PN-EN ISO 16000-32:2014-09); laboratories cite the ISO document. In the iTeh search results (read 03.10.2026) ISO 16000-3:2026 (and its Slovenian adoption SIST ISO 16000-3:2026) appears next to ISO 16000-3:2022; in the scope description of the new edition the concentration range and sampling times are the same, and an alternative sampling on sorbent tubes with thermal desorption and GC-MS is given in Annex A. We have not read the text of the 2026 edition.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, data up to 17.09.2026, read 03.10.2026). The number 16000-3 appears in 9 records at 5 laboratories: AB 023, AB 053, AB 128, AB 934, AB 1207. In the current PCA documents (read 03.10.2026; AB 023 issue no. 31 of 16.07.2025, AB 1207 issue no. 26 of 11.06.2026, AB 128 issue no. 25 of 24.06.2026, AB 934 issue no. 32 of 03.07.2026, AB 053 issue no. 25 of 01.09.2026) the number appears at the same 5 laboratories; in every document the number of page markers equals the number of PDF pages, without repetitions; a search of all PCA documents downloaded from BIP on 03.10.2026 found no laboratories outside the database copy. The form “ISO 16000-3:2022” at AB 053, AB 934 and AB 1207 and in one item of AB 023; without year at AB 128 and in the second item of AB 023. None of these items is suspended. The “Laboratories” tab (query “ISO 16000-3”) shows all 5 Polish laboratories and 7 Czech ones — checked by a tab query on the labcoda.pl production server on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). AB 1207: ambient air and indoor air sampled on tubes with silica gel and DNPH — aldehydes by HPLC-UV, e.g. formaldehyde (0.0002–5) mg/m³ and (0.0002–0.075) mg per sample, propanal, heptanal, octanal, nonanal, with procedure PB-10A. AB 934: indoor air sampled on sorbent tubes — formaldehyde and acetaldehyde (0.0167–3.33) mg/m³ and (0.0001–0.100) mg per sample, HPLC-UV, with instruction IB-81. AB 053: construction products and interior furnishings — aldehyde emission in large and small chambers, formaldehyde (0.001–0.2) mg/m³, acetaldehyde (0.001–0.1) mg/m³, HPLC-UV, together with PN-EN 16516+A1:2020-12. AB 128: plastics, textiles, foams, leather and rubber — emission of carbonyl compounds in an environmental chamber, HPLC-DAD, with instruction BOSMAL/I-7-89. AB 023: in-situ sampling of indoor air (together with ISO 16000-6:2021) and formaldehyde emission from HPL laminates (0.005–15) mg/m³ by the chamber method, together with PN-EN 717-1.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. Ozone: biases results low even at clean-air concentrations, and without a denuder or potassium iodide cartridge the loss is not visible in the result itself — it is revealed by new peaks before the formaldehyde hydrazone (5.2). NO2: in rooms with gas stoves the NO2 derivative may overlap the formaldehyde derivative, depending on the column and conditions (5.1). Acrolein and crotonaldehyde: the standard states that they cannot be accurately quantified by this method (5.1) — a result for them is not a result according to ISO 16000-3. Blank: DNPH contaminated with formaldehyde raises the result, and the blank cartridge and the limit of 0.15 µg per cartridge are the control (5.1, 7.3.1). Flow: validated up to 1.5 l/min, and user-prepared cartridges have a pressure drop of about 19 kPa at 1.5 l/min — a personal pump may not hold the flow (5.1, 7.1.1). Range: laboratory items reach from 0.0002 to 5 mg/m³, i.e. beyond the approximate range of the standard 1 µg/m³–1 mg/m³ (1) — how such a range is covered lies in the laboratories’ procedures. Edition: the iTeh catalogue already lists ISO 16000-3:2026, while the PCA items state 2022 or give no year.

WHAT WE DO NOT GIVE. We do not quote the preparation of cartridges and reagents, sampling conditions, desorption, calibration, chromatographic conditions, formulae, precision or uncertainty data — they lie outside the sample. We do not summarize ISO 16000-2, ISO 16000-6, PN-EN 16516 or PN-EN 717-1 in this entry. We do not give limit or guideline values for formaldehyde in indoor air or emission classes of products.

Method principle

Air is drawn at a constant, measured flow through a cartridge of silica gel coated with acidified 2,4-dinitrophenylhydrazine. Formaldehyde and other aldehydes and ketones react with DNPH to form stable 2,4-dinitrophenylhydrazones retained in the bed. The derivatives are eluted and separated by reversed-phase HPLC with absorbance measured at 360 nm; the air concentration is calculated from the mass of the compound and the volume of air sampled, corrected for the blank cartridge.

Applications

• Formaldehyde and other carbonyl compounds in indoor air, approx. 1 µg/m³–1 mg/m³, sampling 1–24 h or 5–60 min (1)
• Test chamber air — emission of formaldehyde and aldehydes from construction products, furnishings, plastics and laminates (title; items AB 023, AB 053, AB 128)
• Measurements in buildings following the sampling strategy of ISO 16000-2 (introduction)
• Indoor and ambient air — 9 accreditation scope records of 5 laboratories in PCA

Key parameters

Standard

Standard number

ISO 16000-3:2022

Title (PL)

Powietrze wnętrz — Część 3: Oznaczanie formaldehydu i innych związków karbonylowych w powietrzu wnętrz i w powietrzu komór badawczych — Metoda pobierania aktywnego

Title (EN)

Indoor air — Part 3: Determination of formaldehyde and other carbonyl compounds in indoor and test chamber air — Active sampling method

Step-by-step procedure

1. Cartridges

   Check of DNPH blank (< 0.15 µg per cartridge); protection from direct sunlight (5.1). ISO 16000-3:2022 — no PN; in the iTeh catalogue also the 2026 edition (03.10.2026).

2. Sampling

   Flow up to 1.5 l/min, duration 1–24 h or 5–60 min; if ozone is suspected — denuder or KI cartridge (1, 5.2; Clause 10 outside the sample).

3. Transport

   Sealed cartridge containers and transport containers (7.2.1, 7.2.3).

4. Analysis

   Elution of the hydrazones and HPLC with detection at 360 nm, with a blank cartridge (7.3.1; Clause 10 outside the sample).

5. Result

   Air concentration from the mass of the compound and the air volume (Clause 11 outside the sample).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Dry DNPH is explosive, toxic and irritating to eyes and skin (6)
• Perchloric acid above 160 °C may explode on contact with alcohols, wood, cellulose (6)

Frequently asked questions