🧪 PAH in water
In short
Determination of 15 polycyclic aromatic hydrocarbons (PAH) in water by HPLC with fluorescence detection after liquid-liquid extraction with hexane. The test is performed according to PN-EN ISO 17993:2005; Lower end of the standard’s range — drinking water and groundwater: above 0.005 µg/l (each compound separately). The procedure comprises 8 steps; it is used for: Water intended for human consumption — benzo(a)pyrene (0.010 µg/l) and the sum of four PAH (0.10 µg/l) according to Journal of Laws 2026, item 748, Groundwater — at concentrations above 0.005 µg/l for each compound, Surface water — at concentrations above 0.01 µg/l for each compound.
At a glance
- Standard: PN-EN ISO 17993:2005
- Category: Physicochemistry
- Procedure steps: 8
- Compounds determined: 15 PAH of Table 1 of the standard (US EPA list without acenaphthylene)
- Lower end of the standard’s range — drinking water and groundwater: above 0.005 µg/l (each compound separately)
- Lower end of the standard’s range — surface water: above 0.01 µg/l (each compound separately)
Overview
STATUS (as of 29.10.2026). PN-EN ISO 17993:2005 — Polish version, published 5 May 2005, 28 pages, technical body KT 122 (Water Quality — Chemical Testing — Organic Substances), ICS 13.060.50. It implements EN ISO 17993:2003 [IDT] and ISO 17993:2002 [IDT]; it replaced PN-EN ISO 17993:2004 (the English version). The card carries no withdrawal note and no "Replaced by" line — the standard is CURRENT. The German DIN EN ISO 17993:2004-03 is marked as current in the DIN Media catalogue.
SCOPE (clause 1). The method covers the 15 PAH of Table 1 of the standard: naphthalene, acenaphthene, phenanthrene, fluoranthene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, fluorene, anthracene, pyrene, chrysene, benzo(k)fluoranthene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene — in drinking water and groundwater at mass concentrations greater than 0.005 µg/l, and in surface water above 0.01 µg/l (for each compound separately). With some modification it is also suitable for wastewater; it may also be applicable to other PAH, provided it is validated in each case. These are the limits of the standard's scope of application, not the limits of quantification of a particular laboratory. Acenaphthylene, the sixteenth compound of the US EPA list, is not determined by this method because it is not fluorescent (note below Table 1).
EXTRACTION SOLVENT (5.1.1) — HEXANE. The standard also allows other volatile solvents if equivalent or better recovery is demonstrated; replacing hexane with another solvent, e.g. cyclohexane, therefore requires proof of recovery. The standard lists dichloromethane, hexane, N,N-dimethylformamide and acetone as extract clean-up solvents (5.1.2), and acetonitrile and methanol as HPLC solvents (5.1.3).
CONCENTRATION. The principle of the method (clause 3) says only that the extract is concentrated by evaporation and the residue is taken up in a solvent suitable for HPLC analysis. Among the reagents the standard lists nitrogen with a volume fraction of at least 99.999 % (5.4), and among the apparatus a 100 ml reduction flask (6.6, Figure B.1). The description of the evaporation (8.3) lies outside the available excerpt of the standard. The FGSV method developed on the basis of DIN EN ISO 17993 (eluates of road construction materials) concentrates the extract on a rotary evaporator to about 2 ml and then blows off the remaining solvent to dryness with a gentle stream of nitrogen.
SEPARATION AND DETECTION (clause 3). PAH are separated by HPLC on a suitable stationary phase with gradient elution; when only a few PAH are determined, they can be separated isocratically. The standard gives chromatographic conditions and columns as examples in Annex A, which is informative — the column and the gradient programme, and with them the analysis time, are chosen by the laboratory and confirmed by validation. Identification and quantification — with a fluorescence detector with programming of both the excitation and the emission wavelength.
INTERFERENCES (clause 4). Sampling containers — preferably of steel or glass; plastics and other organic materials are avoided during sampling, storage and extraction. In automatic samplers tubing of silicone or rubber is avoided (if present — as short as possible), and the line is rinsed with the water to be sampled before sampling. Samples are protected from direct sunlight and prolonged exposure to light; during storage PAH may be lost by adsorption on the container walls, and the extent of the losses depends on the storage time. In HPLC, compounds that fluoresce or quench fluorescence and co-elute with the PAH interfere — interference is indicated by peaks that are unsymmetrical and broader than the peak of the reference compound; depending on the selectivity of the phase this may concern naphthalene and phenanthrene. Incomplete removal of the solvents used in sample pretreatment (hexane, acetone, dichloromethane) impairs the reproducibility of retention times and gives broadened or double peaks, especially for 2- and 3-ring PAH. The separation of dibenzo(a,h)anthracene and indeno(1,2,3-cd)pyrene can be critical — when resolution is incomplete, the peak integration shall be checked and corrected if necessary. Perylene is usually not resolved from benzo(b)fluoranthene; its peak is suppressed by the choice of wavelength, and in the isocratic variant for drinking water perylene should be included in the calibration.
DRINKING WATER — REQUIREMENTS OF THE REGULATION. Regulation of the Minister of Health of 22 May 2026 (Journal of Laws 2026, item 748), Annex 1 Part B: benzo(a)pyrene 0.010 µg/l (No 8); PAH 0.10 µg/l as the sum of benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(ghi)perylene and indeno(1,2,3-cd)pyrene (No 33). Annex 4 Part B: the method must measure concentrations equal to the parametric value at a limit of quantification not greater than 30 % of that value, with a measurement uncertainty not greater than 50 % for benzo(a)pyrene (where this cannot be achieved — the best available technique, up to 60 %) and 40 % for PAH (for individual compounds at 25 % of the parametric value). For benzo(a)pyrene this means a limit of quantification of 0.003 µg/l — lower than the lower end of the standard's scope for drinking water (0.005 µg/l), so the laboratory must demonstrate it by its own validation.
WHAT WE DO NOT GIVE HERE. The publicly available excerpt of the standard (the publisher's sample) ends at 6.7 of the apparatus clause. Sampling (clause 7), sample and solvent volumes, extraction time, drying, concentration and clean-up of the extract (8.1–8.4), HPLC conditions (8.5 and Annex A), calibration (8.6), recovery and the blank (8.8–8.9), calculation and precision data (clauses 9–10) lie outside it — we know only their titles from the table of contents. Figures in the procedure steps marked as an "example" come from the cited methods based on this standard, not from the standard itself.
Method principle
PAH are extracted from the water sample with hexane (another volatile solvent — only once equivalent or better recovery has been demonstrated). The extract is concentrated by evaporation and the residue is taken up in a solvent suitable for HPLC analysis. Extracts of surface water and of more contaminated samples are, if necessary, cleaned up before analysis by chromatography on silica gel.
PAH are separated by HPLC on a suitable stationary phase with gradient elution (when only a few PAH are determined — also isocratically), and are identified and quantified with a fluorescence detector with programming of both the excitation and the emission wavelength. For this reason the method does not cover acenaphthylene, which is not fluorescent.
Applications
- Water intended for human consumption — benzo(a)pyrene (0.010 µg/l) and the sum of four PAH (0.10 µg/l) according to Journal of Laws 2026, item 748
- Groundwater — at concentrations above 0.005 µg/l for each compound
- Surface water — at concentrations above 0.01 µg/l for each compound
- Wastewater — after some modification of the method (scope of the standard)
- PAH other than the 15 of Table 1 — the method may be applicable, provided it is validated in each case
Key parameters
| Parameter | Value |
|---|---|
| Compounds determined | 15 PAH of Table 1 of the standard (US EPA list without acenaphthylene) |
| Lower end of the standard’s range — drinking water and groundwater | above 0.005 µg/l (each compound separately) |
| Lower end of the standard’s range — surface water | above 0.01 µg/l (each compound separately) |
| Extraction solvent | hexane; another volatile solvent once equivalent or better recovery has been demonstrated (5.1.1) |
| Detection | fluorescence, with programming of the excitation and emission wavelengths |
| Column and gradient programme | chosen by the laboratory — examples in informative Annex A |
Standard
- Standard number
- PN-EN ISO 17993:2005
- Title (PL)
- Jakość wody — Oznaczanie 15 wielopierścieniowych węglowodorów aromatycznych (WWA) w wodzie metodą HPLC z detekcją fluorescencyjną po ekstrakcji ciecz-ciecz
- Title (EN)
- Water quality — Determination of 15 polycyclic aromatic hydrocarbons (PAH) in water by HPLC with fluorescence detection after liquid-liquid extraction
Step-by-step procedure
-
Sampling and sample storage
Brown glass bottles of 1000 ml, preferably of known mass (6.1); containers preferably of steel or glass, without plastics; protect samples from light. PAH losses by adsorption on the walls depend on the storage time (4.1). Guidance on sampling and preservation: ISO 5667-2 and ISO 5667-3; clause 7 of the standard lies outside the available excerpt.
-
Liquid-liquid extraction
With hexane (8.1); apparatus of the standard: a magnetic stirrer for stirring the extraction solvent and a 1000 ml separating funnel. The available excerpt of the standard does not give volumes or time. Example from the FGSV method based on this standard: 100 ml of sample, 10 ml of n-hexane (or cyclohexane), stirring with a magnetic stirrer for 60 min at 1000 rpm, the organic phase collected with a micro-separator.
-
Drying the extract
Clause 8.2 of the standard; among the reagents the standard lists anhydrous sodium sulfate precleaned at 500 °C and activated 0.4 nm molecular sieves. The details lie outside the available excerpt.
-
Concentration
The extract is concentrated by evaporation (principle of the method, 8.3), in a 100 ml reduction flask (Figure B.1); the standard lists nitrogen with a purity of at least 99.999 %. FGSV example: rotary evaporator to about 2 ml, then a gentle stream of nitrogen to dryness. Residues of hexane, acetone or dichloromethane in the HPLC solution impair the reproducibility of retention times and the peak shape (4.2).
-
Extract clean-up — if necessary
Extracts of surface water and of more contaminated samples are cleaned up by chromatography on silica gel (principle of the method, 8.4).
-
Transfer to an HPLC solvent
The residue after evaporation is dissolved in a solvent suitable for HPLC — acetonitrile or methanol, depending on the mobile phase (clause 3, 5.1.3). FGSV example: acetonitrile/water 1:1, 2 ml flask.
-
HPLC separation and detection
The stationary phase and the gradient programme are chosen by the laboratory (8.5; examples of conditions and columns — informative Annex A), so the analysis time results from the chosen conditions, not from the standard. Fluorescence detector with programming of the excitation and emission wavelengths. Check the integration of the dibenzo(a,h)anthracene / indeno(1,2,3-cd)pyrene pair. Example of a short routine method (Thermo Fisher application note, water): column 100 × 4.6 mm, 3 µm, 17 PAH separated by a gradient in 16 min, and the whole programme including the return of the column to the initial conditions ends at the 20th minute.
-
Calibration and quality control
At least five calibration solutions (5.9; among the references of the standard: ISO 8466-1 — statistical evaluation of the linear calibration function). The concentration of the stock solution can only be checked by comparison with an independent, preferably certified, standard, and the reference solutions are checked regularly. Recovery and the blank have separate clauses in the standard (8.8–8.9), whose content lies outside the available excerpt. For drinking water: limit of quantification not greater than 30 % of the parametric value, uncertainty up to 50 % (benzo(a)pyrene) or 40 % (PAH) — Journal of Laws 2026, item 748, Annex 4 Part B.
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Laboratory glassware | cleaned to eliminate all interferences, e.g. detergent and hot water, drying for about 15–30 min at about 120 °C, after cooling rinsing with acetone, sealing and storage in a clean environment; glassware that has been in contact with wastewater or with samples of high PAH concentration is not used for drinking water (clause 6) | — |
| Brown glass bottles | narrow-necked, flat-bottomed, 1000 ml, with glass stopper, preferably of known mass (6.1) | — |
| Magnetic stirrer | with stirring bars of glass or PTFE-coated — for stirring the extraction solvent (6.2) | — |
| Separating funnel | 1000 ml, with PTFE stopcock and glass stopper (6.3) | — |
| Conical flasks and microlitre syringes | flasks of 100 ml and 250 ml with glass stopper; syringes of 500 µl and 1000 µl (6.4–6.5) | — |
| Reduction flask | 100 ml, made according to Figure B.1 of the standard (6.6) | — |
| Centrifuge | with rotor for centrifuge tubes with tapered bottoms, 50 ml, Figure B.2 of the standard (6.7) | — |
| Device for evaporating the extract | its type is not given in the available excerpt of the standard; example from the FGSV method based on this standard — rotary evaporator to about 2 ml, then a gentle stream of nitrogen | — |
| HPLC system with fluorescence detector | gradient elution, programming of the excitation and emission wavelengths; the column is chosen by the laboratory (examples: informative Annex A of the standard) | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Hexane | — | C₆H₁₄ — extraction solvent (5.1.1); another volatile solvent is permitted once equivalent or better recovery has been demonstrated. Reagents of recognized analytical grade, e.g. “for residue analysis” or “for HPLC analysis” |
| Dichloromethane, N,N-dimethylformamide, acetone, hexane | — | extract clean-up solvents (5.1.2). Dichloromethane often contains stabilizers (e.g. ethanol, amylene) that may change the elution strength; without a stabilizer radicals may form that degrade PAH — they are indicated by hydrogen chloride, detected by measuring the pH of water after shaking with dichloromethane |
| Acetonitrile and methanol | — | HPLC solvents (5.1.3); the stock solutions of the standards are prepared in acetonitrile |
| Water | — | distilled or of equivalent purity, with the lowest possible fluorescence; the blank is to confirm that the reagents do not contain PAH in detectable concentrations (clause 5) |
| Sodium sulfate, anhydrous | 7757-82-6 | Na₂SO₄, precleaned by heating to 500 °C (5.3) |
| Sodium thiosulfate pentahydrate | 10102-17-7 | Na₂S₂O₃·5H₂O (5.2); its use is described in a part of the standard outside the available excerpt |
| Nitrogen | 7727-37-9 | with a volume fraction of at least 99.999 % (5.4) |
| Silica gel and molecular sieves | — | silica gel with an average particle size of about 40 µm, stored in a desiccator for maximum activity (prepacked cartridges are available) — for the clean-up of extracts; molecular sieve beads with a pore diameter of 0.4 nm, completely activated (5.5–5.6) |
| PAH standards | — | compounds of Table 1 — because of their dangerous nature, commercially available, preferably certified, solutions are recommended; stock solutions of single compounds and of a certified mixture in acetonitrile, e.g. 10 µg/ml, stable for at least a year in the dark at room temperature; at least five calibration solutions in methanol or acetonitrile, depending on the mobile phase — e.g. 50 µl of the stock solution made up in a 5 ml flask gives 100 pg of each compound in 1 µl (5.7–5.9) |
Health and safety (OHS)
- Some of the PAH determined are considered carcinogenic or are suspected of being carcinogenic; acetonitrile and hexane are toxic (warning and introduction of the standard)
- Standards: because of the dangerous nature of PAH the standard recommends commercially available, preferably certified, solutions; avoid skin contact (5.7)
- Health and safety practices and compliance with national regulations are the responsibility of the user of the standard — the standard does not address all safety problems
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-EN ISO 17993:2005 — “Water quality — Determination of 15 polycyclic aromatic hydrocarbons (PAH) in water by HPLC with fluorescence detection after liquid-liquid extraction”.
How does this method work?
PAH are extracted from the water sample with hexane (another volatile solvent — only once equivalent or better recovery has been demonstrated). The extract is concentrated by evaporation and the residue is taken up in a solvent suitable for HPLC analysis.
What is the measuring range and accuracy?
Compounds determined: 15 PAH of Table 1 of the standard (US EPA list without acenaphthylene); Lower end of the standard’s range — drinking water and groundwater: above 0.005 µg/l (each compound separately); Lower end of the standard’s range — surface water: above 0.01 µg/l (each compound separately); Extraction solvent: hexane; another volatile solvent once equivalent or better recovery has been demonstrated (5.1.1).
How long does the test take?
The procedure comprises 8 steps. The standard does not give a duration for every stage — the laboratory's own procedure decides.
What equipment is required?
Laboratory glassware, Brown glass bottles, Magnetic stirrer, Separating funnel, Conical flasks and microlitre syringes, Reduction flask, Centrifuge, Device for evaporating the extract, HPLC system with fluorescence detector.
Where is this test used?
Water intended for human consumption — benzo(a)pyrene (0.010 µg/l) and the sum of four PAH (0.10 µg/l) according to Journal of Laws 2026, item 748; Groundwater — at concentrations above 0.005 µg/l for each compound; Surface water — at concentrations above 0.01 µg/l for each compound; Wastewater — after some modification of the method (scope of the standard); PAH other than the 15 of Table 1 — the method may be applicable, provided it is validated in each case.
What safety precautions apply?
Some of the PAH determined are considered carcinogenic or are suspected of being carcinogenic; acetonitrile and hexane are toxic (warning and introduction of the standard); Standards: because of the dangerous nature of PAH the standard recommends commercially available, preferably certified, solutions; avoid skin contact (5.7); Health and safety practices and compliance with national regulations are the responsibility of the user of the standard — the standard does not address all safety problems.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-EN ISO 17993.