ISO 7981-1:2005

Water quality — Determination of polycyclic aromatic hydrocarbons (PAH) — Part 1: Determination of six PAH by high-performance thin-layer chromatography with fluorescence detection after liquid-liquid extraction

ISO 7981-1:2005 specifies the determination of six selected polycyclic aromatic hydrocarbons (PAH) in drinking water. The 6 PAH are: fluoranthene, benzo[b]fluoranthene, benzo[a]pyrene, benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, and benzo[ghi]perylene The screening method (method A) described excludes those samples containing less than 20 % of the referenced limit values. The quantitative method (method B) described has a working range of 40 ng/l to 240 ng/l (sum of 6 PAH). Higher concentrations may be determined by using a smaller aliquot of the sample. With some modifications, this method is also applicable for the analysis of ground waters and moderately polluted surface waters.

Qualité de l'eau — Détermination des hydrocarbures aromatiques polycycliques (HAP) — Partie 1: Dosage de six HAP par chromatographie de haute performance sur couche mince avec détection fluorimétrique à la suite d'une extraction liquide-liquide

Kakovost vode - Določevanje policikličnih aromatskih ogljikovodikov (PAH) - 1. del: Določevanje šestih policikličnih aromatskih ogljikovodikov s tankoplastno kromatografijo visoke ločljivosti s fluorescenčno detekcijo po tekočinsko-tekočinski ekstrakciji

General Information

• Status: Published
• Publication Date: 26-Jun-2005
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: ISO/TC 147/SC 2 - Physical, chemical and biochemical methods
• Drafting Committee: ISO/TC 147/SC 2 - Physical, chemical and biochemical methods
• Current Stage: 9060 - Close of review
• Start Date: 04-Mar-2030
• Ref Project: SIST ISO 7981-1:2007 - Water quality -- Determination of polycyclic aromatic hydrocarbons (PAH) -- Part 1: Determination of six PAH by high-performance thin-layer chromatography with fluorescence detection after liquid-liquid extraction

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2007
.DNRYRVWYRGH'RORþHYDQMHSROLFLNOLþQLKDURPDWVNLKRJOMLNRYRGLNRY3$+
GHO'RORþHYDQMHãHVWLKSROLFLNOLþQLKDURPDWVNLKRJOMLNRYRGLNRYVWDQNRSODVWQR
NURPDWRJUDILMRYLVRNHORþOMLYRVWLVIOXRUHVFHQþQRGHWHNFLMRSRWHNRþLQVNR
WHNRþLQVNLHNVWUDNFLML
Water quality -- Determination of polycyclic aromatic hydrocarbons (PAH) -- Part 1:
Determination of six PAH by high-performance thin-layer chromatography with
fluorescence detection after liquid-liquid extraction
Qualité de l'eau -- Détermination des hydrocarbures aromatiques polycycliques (HAP) --
Partie 1: Dosage de six HAP par chromatographie de haute performance sur couche
mince avec détection fluorimétrique à la suite d'une extraction liquide-liquide
Ta slovenski standard je istoveten z: ISO 7981-1:2005
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 7981-1
First edition
2005-06-15
Water quality — Determination of
polycyclic aromatic hydrocarbons
(PAH) —
Part 1:
Determination of six PAH by high-
performance thin-layer chromatography
with fluorescence detection after
liquid-liquid extraction
Qualité de l'eau — Détermination des hydrocarbures aromatiques
polycycliques (HAP) —
Partie 1: Dosage de six HAP par chromatographie de haute
performance sur couche mince avec détection fluorimétrique à la suite
d'une extraction liquide-liquide

Reference number
©
ISO 2005
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2005
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2005 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Principle. 1
3 Interferences . 2
4 Reagents. 3
5 Apparatus . 4
6 Sampling. 5
7 Procedure . 6
8 Evaluation. 8
9 Calibration . 11
10 Determination of the recovery. 13
11 Blank measurements. 13
12 Calculation. 13
13 Expression of results . 14
14 Test report . 15
15 Accuracy. 15
Annex A (informative) R values of the six PAH under various chromatographic conditions . 16
f
Annex B (informative) Spectroscopic identification. 17
Annex C (informative) Examples for the construction of special apparatus . 18
Annex D (informative) Accuracy . 21
Bibliography . 22

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 7981-1 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
ISO 7981 consists of the following parts, under the general title Water quality — Determination of polycyclic
aromatic hydrocarbons (PAH):
 Part 1: Determination of six PAH by high-performance thin-layer chromatography with fluorescence
detection after liquid-liquid extraction
 Part 2: Determination of six PAH by high-performance liquid chromatography with fluorescence detection
after liquid-liquid extraction
iv © ISO 2005 – All rights reserved

Introduction
Polycyclic aromatic hydrocarbons (PAH) are present in nearly all types of waters. These substances are
adsorbed on solids (sediments, suspended matter) as well as dissolved in the liquid phase.
Some PAH are known or suspected to cause cancer. The maximum acceptable levels of PAH in waters
[1] [2] [3] [4]
intended for human consumption are given in European Legislation .
The sum of the mass concentrations of the six PAH specified in this part of ISO 7981 normally is about
0,01 µg/l to 0,05 µg/l in ground water and up to 1 µg/l in surface water.
INTERNATIONAL STANDARD ISO 7981-1:2005(E)

Water quality — Determination of polycyclic aromatic
hydrocarbons (PAH) —
Part 1:
Determination of six PAH by high-performance thin-layer
chromatography with fluorescence detection after liquid-liquid
extraction
WARNING — Some substances being measured are presumed to be carcinogenic. Acetonitrile and
hexane are harmful.
Persons using this part of ISO 7981 should be familiar with normal laboratory practise. This standard
does not purport to address all of the safety problems, if any, associated with its use. It is the
responsibility of the user of this part of ISO 7981 to establish appropriate safety and health practices
and to ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted according to this part of ISO 7981 be
carried out by suitably trained staff.
1 Scope
This part of ISO 7981 specifies the determination of six selected PAH in drinking water by high-performance
thin-layer chromatography with fluorescence detection after liquid-liquid extraction. The six PAH are:
fluoranthene, benzo[b]fluoranthene, benzo[a]pyrene, benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, and
benzo[ghi]perylene (see Table 1).
A screening method (method A) is described to exclude those samples containing less than 20 % of the limit
values given in References [1], [2], [3] and [4].
A quantitative method (method B) is also described, with a working range of 40 ng/l to 240 ng/l (sum of
6 PAH). Higher concentrations can be determined by using a smaller aliquot of the sample.
With some modifications, this method is also applicable for the analysis of ground waters and moderately
polluted surface waters.
2 Principle
Since PAH can to a large extent be adsorbed on particulate matter, the whole test sample is analysed.
NOTE For the analysis of surface water, a differentiation between dissolved and undissolved PAH may be desirable,
but this is not relevant for drinking water.
PAH are extracted from the water sample by liquid-liquid extraction. The extract is evaporated to dryness and
the residue is taken up in a solvent and analysed.
Extracts of surface waters and other contaminated water samples should be cleaned prior to analysis (7.4).
PAH are then separated by high-performance thin-layer chromatography (HPTLC) on appropriate stationary
phases and detected either visually or by in situ fluorescence measurement at constant or differing
wavelength combinations.
Table 1 — Polycyclic aromatic hydrocarbons determinable by this method
Chemical Carbon
Name Molar mass CAS-number Structure
formula fraction
g/mol
C H
Fluoranthene 202,26 95,0 206-44-0
16 10
C H
Benzo[b]fluoranthene 252,32 95,2 205-99-2
20 12
C H
Benzo[a]pyrene 252,32 95,2 50-32-8
20 12
C H
Benzo[k]fluoranthene 252,32 95,2 207-08-9
20 12
C H
Indeno[1,2,3-cd]pyrene 276,34 95,6 193-39-5
22 12
C H
Benzo[ghi]perylene 276,34 95,6 191-24-2
22 12
3 Interferences
3.1 Interferences with screening method (method A)
Other compounds and/or impurities can interfere in the screening method, thus the use of spectroscopic
identification is recommended in order to lower the occurrence of false positives in screening test samples.
It may be necessary to clean coloured extracts or test samples known to contain other organic substances on
silica prior to analysis (7.4).
3.2 Interferences with sampling and extraction
Use sampling containers made of materials (preferably of glass or steel) that do not affect the test sample
during the contact time. Avoid plastics and other organic materials during sampling, sample storage or
extraction.
2 © ISO 2005 – All rights reserved

If automatic samplers are used, avoid the use of silicone or rubber material for the tubes. If present, make
sure that the tubes are as short as possible. Rinse the sampling line with the water to be sampled before the
test sample is taken. ISO 5667-2 and ISO 5667-3 can be used for guidance.
Keep the samples from direct sunlight and prolonged exposure to light.
During storage of the test sample, losses of PAH can occur due to adsorption on the walls of the containers.
The extent of the losses depends on the storage time.
3.3 Interferences with HPTLC
Substances that exhibit either fluorescence or quenching and co-elute with the PAH to be determined can
interfere with the determination. These interferences can lead to incompletely resolved signals and can,
depending on their magnitude, affect the accuracy and precision of the analytical results. Band overlap will
make an interpretation of the result impossible. Unsymmetrical bands and bands broader than the
corresponding bands of the reference substance suggest interferences.
The identity and purity of the bands can be checked by recording the excitation and emission spectra.
4 Reagents
Use only reagents of recognized analytical grade (e.g. “for residue analysis” or “for HPLC analysis”) as far as
available, and
...

INTERNATIONAL ISO
STANDARD 7981-1
First edition
2005-06-15
Water quality — Determination of
polycyclic aromatic hydrocarbons
(PAH) —
Part 1:
Determination of six PAH by high-
performance thin-layer chromatography
with fluorescence detection after
liquid-liquid extraction
Qualité de l'eau — Détermination des hydrocarbures aromatiques
polycycliques (HAP) —
Partie 1: Dosage de six HAP par chromatographie de haute
performance sur couche mince avec détection fluorimétrique à la suite
d'une extraction liquide-liquide

Reference number
©
ISO 2005
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2005
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2005 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Principle. 1
3 Interferences . 2
4 Reagents. 3
5 Apparatus . 4
6 Sampling. 5
7 Procedure . 6
8 Evaluation. 8
9 Calibration . 11
10 Determination of the recovery. 13
11 Blank measurements. 13
12 Calculation. 13
13 Expression of results . 14
14 Test report . 15
15 Accuracy. 15
Annex A (informative) R values of the six PAH under various chromatographic conditions . 16
f
Annex B (informative) Spectroscopic identification. 17
Annex C (informative) Examples for the construction of special apparatus . 18
Annex D (informative) Accuracy . 21
Bibliography . 22

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 7981-1 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
ISO 7981 consists of the following parts, under the general title Water quality — Determination of polycyclic
aromatic hydrocarbons (PAH):
 Part 1: Determination of six PAH by high-performance thin-layer chromatography with fluorescence
detection after liquid-liquid extraction
 Part 2: Determination of six PAH by high-performance liquid chromatography with fluorescence detection
after liquid-liquid extraction
iv © ISO 2005 – All rights reserved

Introduction
Polycyclic aromatic hydrocarbons (PAH) are present in nearly all types of waters. These substances are
adsorbed on solids (sediments, suspended matter) as well as dissolved in the liquid phase.
Some PAH are known or suspected to cause cancer. The maximum acceptable levels of PAH in waters
[1] [2] [3] [4]
intended for human consumption are given in European Legislation .
The sum of the mass concentrations of the six PAH specified in this part of ISO 7981 normally is about
0,01 µg/l to 0,05 µg/l in ground water and up to 1 µg/l in surface water.
INTERNATIONAL STANDARD ISO 7981-1:2005(E)

Water quality — Determination of polycyclic aromatic
hydrocarbons (PAH) —
Part 1:
Determination of six PAH by high-performance thin-layer
chromatography with fluorescence detection after liquid-liquid
extraction
WARNING — Some substances being measured are presumed to be carcinogenic. Acetonitrile and
hexane are harmful.
Persons using this part of ISO 7981 should be familiar with normal laboratory practise. This standard
does not purport to address all of the safety problems, if any, associated with its use. It is the
responsibility of the user of this part of ISO 7981 to establish appropriate safety and health practices
and to ensure compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted according to this part of ISO 7981 be
carried out by suitably trained staff.
1 Scope
This part of ISO 7981 specifies the determination of six selected PAH in drinking water by high-performance
thin-layer chromatography with fluorescence detection after liquid-liquid extraction. The six PAH are:
fluoranthene, benzo[b]fluoranthene, benzo[a]pyrene, benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, and
benzo[ghi]perylene (see Table 1).
A screening method (method A) is described to exclude those samples containing less than 20 % of the limit
values given in References [1], [2], [3] and [4].
A quantitative method (method B) is also described, with a working range of 40 ng/l to 240 ng/l (sum of
6 PAH). Higher concentrations can be determined by using a smaller aliquot of the sample.
With some modifications, this method is also applicable for the analysis of ground waters and moderately
polluted surface waters.
2 Principle
Since PAH can to a large extent be adsorbed on particulate matter, the whole test sample is analysed.
NOTE For the analysis of surface water, a differentiation between dissolved and undissolved PAH may be desirable,
but this is not relevant for drinking water.
PAH are extracted from the water sample by liquid-liquid extraction. The extract is evaporated to dryness and
the residue is taken up in a solvent and analysed.
Extracts of surface waters and other contaminated water samples should be cleaned prior to analysis (7.4).
PAH are then separated by high-performance thin-layer chromatography (HPTLC) on appropriate stationary
phases and detected either visually or by in situ fluorescence measurement at constant or differing
wavelength combinations.
Table 1 — Polycyclic aromatic hydrocarbons determinable by this method
Chemical Carbon
Name Molar mass CAS-number Structure
formula fraction
g/mol
C H
Fluoranthene 202,26 95,0 206-44-0
16 10
C H
Benzo[b]fluoranthene 252,32 95,2 205-99-2
20 12
C H
Benzo[a]pyrene 252,32 95,2 50-32-8
20 12
C H
Benzo[k]fluoranthene 252,32 95,2 207-08-9
20 12
C H
Indeno[1,2,3-cd]pyrene 276,34 95,6 193-39-5
22 12
C H
Benzo[ghi]perylene 276,34 95,6 191-24-2
22 12
3 Interferences
3.1 Interferences with screening method (method A)
Other compounds and/or impurities can interfere in the screening method, thus the use of spectroscopic
identification is recommended in order to lower the occurrence of false positives in screening test samples.
It may be necessary to clean coloured extracts or test samples known to contain other organic substances on
silica prior to analysis (7.4).
3.2 Interferences with sampling and extraction
Use sampling containers made of materials (preferably of glass or steel) that do not affect the test sample
during the contact time. Avoid plastics and other organic materials during sampling, sample storage or
extraction.
2 © ISO 2005 – All rights reserved

If automatic samplers are used, avoid the use of silicone or rubber material for the tubes. If present, make
sure that the tubes are as short as possible. Rinse the sampling line with the water to be sampled before the
test sample is taken. ISO 5667-2 and ISO 5667-3 can be used for guidance.
Keep the samples from direct sunlight and prolonged exposure to light.
During storage of the test sample, losses of PAH can occur due to adsorption on the walls of the containers.
The extent of the losses depends on the storage time.
3.3 Interferences with HPTLC
Substances that exhibit either fluorescence or quenching and co-elute with the PAH to be determined can
interfere with the determination. These interferences can lead to incompletely resolved signals and can,
depending on their magnitude, affect the accuracy and precision of the analytical results. Band overlap will
make an interpretation of the result impossible. Unsymmetrical bands and bands broader than the
corresponding bands of the reference substance suggest interferences.
The identity and purity of the bands can be checked by recording the excitation and emission spectra.
4 Reagents
Use only reagents of recognized analytical grade (e.g. “for residue analysis” or “for HPLC analysis”) as far as
available, and only distilled water or water of equivalent purity showing the lowest possible fluorescence.
Monitor the blank to guarantee that the reagents do not contain PAH in detectable concentrations (see
Clause 11).
4.1 Solvents
4.1.1 Extraction and clean-up solvents
4.1.1.1 Cyclohexane, C H
6 12
4.1.1.2 Hexane, C H
6 14
4.1.1.3 Dichloromethane, CH Cl
2 2
Other volatile solvents may be used as well, if it is proved that the recovery is equivalent or better.
NOTE Dichloromethane often contains stabilizers, e.g. ethanol or amylene. Stabilizers can influence the elution
strength of the eluent. Without stabilizer, free radicals might develop. This can lead to degradation of PAH. The presence
of hydrogen chloride indicates the presence of radicals. Hydrogen chloride can be determined by extracting
dichloromethane with water and measuring the pH value.
4.1.2 HPTLC solvents
4.1.2.1 Methanol, CH OH
4.1.2.2 Acetonitrile, CH CN
4.1.2.3 2,4-dimethyl-3-oxypentane (diisopropyl ether), C H O
6 14
4.1.2.4 2-propanol (isopropanol), C H OH
3 7
4.2 Sodium thiosulfate pentahydrate, Na S O ·5H O
2 2 3 2
4.3 Sodium chloride, NaCl
4.4 Sodium sulfate, Na SO , anhydrous, precleaned by heating to 500 °C.
2 4
4.5 Nitrogen, having a purity (volume fraction) of at least 99,999 %.
4.6 Silica, with an average particle size of approximately 4
...