SIST ISO 27108:2011
Water quality - Determination of selected plant treatment agents and biocide products - Method using solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS)
Water quality - Determination of selected plant treatment agents and biocide products - Method using solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS)
This International Standard specifies a method for the determination of the dissolved amount of selected plant treatment agents and biocide products in drinking water, ground water and surface water by solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The limit of determination depends on the matrix, on the specific compound to be analysed and on the sensitivity of the mass spectrometer. For most plant treatment agents and biocides to which this International Standard applies, it is at least 0,05 µg/l. Validation data related to a concentration range between 0,05 µg/l and 0,3 µg/l have been demonstrated in an interlaboratory trial.
This method may be applicable to other compounds not explicitly covered by this International Standard or to other types of water. However, it is necessary to verify the applicability of this method for these special cases. NOTE Determinations by this International Standard are performed on small sample amounts (e.g. sample volumes between 8 ml and 16 ml).
Qualité de l'eau - Détermination d'agents de traitement et de produits d'usine sélectionnés - Méthode utilisant une micro-extraction en phase solide (MEPS) suivie d'une chromatographie en phase gazeuse-spectrométrie de masse (CG-SM)
L'ISO 27108:2010 sp�cifie une m�thode pour la d�termination de la quantit� d'agents de traitement et de produits d'usine s�lectionn�s dissous dans l'eau potable, les eaux souterraines et les eaux de surface par micro-extraction en phase solide (MEPS) suivie d'une chromatographie en phase gazeuse-spectrom�trie de masse (CG-SM). La limite de la d�termination d�pend de la matrice, du compos� sp�cifique � analyser et de la sensibilit� du spectrom�tre de masse. Pour la plupart des agents de traitement et de produits d'usine auxquels l'ISO 27108:2010 s'applique, elle est d'au moins 0,05 �g/l. Les donn�es de validation relatives � une gamme de concentrations comprises entre 0,05 �g/l et 0,3 �g/l ont �t� d�montr�es lors d'un essai interlaboratoires.
Cette m�thode peut �tre applicable � d'autres compos�s qui ne sont pas explicitement trait�s dans l'ISO 27108:2010 ou � d'autres types d'eau. Toutefois, il est n�cessaire de v�rifier l'applicabilit� de cette m�thode � ces cas particuliers.
Kakovost vode - Določevanje izbranih sredstev za zaščito rastlin in biocidov - Metoda plinske kromatografije/masne spektrometrije (GC/MS) po mikroekstrakciji na trdni fazi (SPME)
Ta mednarodni standard opredeljuje metodo določevanja raztopljene količine izbranih sredstev za zaščito rastlin in biocidov v pitni vodi, podtalni vodi in površinski vodi z mikroekstrakcijo na trdni fazi (SPME), ki ji sledi plinska kromatografija - masna spektrometrija (GC-MS). Meja določevanja je odvisna od matrice, od določene spojine za analizo in od občutljivosti masnega spektrometra. Za večino sredstev za zaščito rastlin, za katere velja ta mednarodni standard, je ta vsaj 0,05 µg/l. Validacijski podatki, ki se nanašajo na razpon koncentracije med 0,05 µg/l in 0,3 µg/l, so bili izkazani v medlaboratorijskem preskusu.
Ta metoda se lahko uporablja za druge spojine, ki niso izrecno zajete v tem mednarodnem standardu, ali za druge vrste vode. Vendar je treba potrditi uporabo te metode za take posebne primere. OPOMBA: Določevanje po tem mednarodnem standardu se izvaja na majhni količini vzorca (npr. volumen vzorca med 8 ml in 16 ml).
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INTERNATIONAL ISO
STANDARD 27108
First edition
2010-04-15
Water quality — Determination of
selected plant treatment agents and
biocide products — Method using solid-
phase microextraction (SPME) followed
by gas chromatography-mass
spectrometry (GC-MS)
Qualité de l'eau — Détermination d'agents de traitement et de produits
d'usine sélectionnés — Méthode utilisant une micro-extraction en phase
solide (MEPS) suivie d'une chromatographie en phase gazeuse-
spectrométrie de masse (CG-SM)
Reference number
ISO 27108:2010(E)
©
ISO 2010
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ISO 27108:2010(E)
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ISO 27108:2010(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Principle.1
4 Interferences .2
5 Reagents.4
6 Apparatus.5
7 Sampling and sample pretreatment .6
8 Procedure.6
9 Calibration.8
10 Calculation .11
11 Expression of results.11
12 Test report.11
Annex A (informative) Examples of gas chromatograms for compounds listed in Table 1 .12
Annex B (informative) Mass spectra of compounds of Table 1 (full-scan, EI, 70 eV).21
Annex C (informative) Precision data .35
Annex D (informative) General information about SPME .36
Bibliography.37
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ISO 27108:2010(E)
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 27108 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
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ISO 27108:2010(E)
Introduction
In recent years, ground water contamination as well as surface water contamination by pesticides has become
a matter of public concern. Identification and quantification of pesticides at trace level concentrations often
require both high sensitive chromatographic equipment and effective enrichment steps. In the analysis of
aqueous samples, sample preparation techniques including solid-phase extraction (SPE) are frequently the
most time-consuming steps and in many cases can be effectively replaced by solid-phase microextraction
(SPME).
When using this International Standard, it may be necessary in some cases to determine whether and to what
extent particular problems could require the specification of additional marginal conditions.
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INTERNATIONAL STANDARD ISO 27108:2010(E)
Water quality — Determination of selected plant treatment
agents and biocide products — Method using solid-phase
microextraction (SPME) followed by gas chromatography-mass
spectrometry (GC-MS)
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This International Standard does not purport to address all of the safety problems, if any,
associated with its use. It is the responsibility of the user 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 International Standard
be carried out by suitably trained staff.
1 Scope
This International Standard specifies a method for the determination of the dissolved amount of selected plant
treatment agents and biocide products in drinking water, ground water and surface water by solid-phase
microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The limit of
determination depends on the matrix, on the specific compound to be analysed and on the sensitivity of the
mass spectrometer. For most plant treatment agents and biocides to which this International Standard applies,
it is at least 0,05 µg/l. Validation data related to a concentration range between 0,05 µg/l and 0,3 µg/l have
been demonstrated in an interlaboratory trial.
This method may be applicable to other compounds not explicitly covered by this International Standard or to
other types of water. However, it is necessary to verify the applicability of this method for these special cases.
NOTE Determinations by this International Standard are performed on small sample amounts (e.g. sample volumes
between 8 ml and 16 ml).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Guidance on the preservation and handling of water
samples
3 Principle
Substances under investigation are extracted from the water sample by solid-phase microextraction (SPME)
according to their equilibrium of distribution. The extraction is performed by a chemically modified fused-silica
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ISO 27108:2010(E)
fibre, the surface of which is coated with a suitable adsorbent polymer. During extraction, the fibre is
immersed in the liquid sample. After completion of the extraction procedure, the fibre is drawn back into the
needle, removed from the sample vial, and introduced directly into the GC injector. The analytes are
transferred to the GC column by thermal desorption.
The analytes are separated, identified and quantified by means of capillary gas chromatography with mass
spectrometric detection (GC-MS) using electron impact (EI) ionisation mode.
Table 1 — Plant treatment agents and biocide products determined by this method
Reference No. in example
Molar mass
chromatograms of Figure
Name Molecular formula CAS registry No.
g/mol A.1 A.2 A.3
Dichlobenil C H ClN 1194-65-6 172,0 1 1 1
7 3 2
Desethylatrazine C H ClN 6190-65-4 187,6 2 2 3
6 10 5
Desethylterbutylazine C H ClN 30125-63-4 201,7 3 3 2
7 12 5
Simazine C H ClN 122-34-9 201,7 4 4 7
7 12 5
Atrazine C H ClN 1912-24-9 215,7 6 5 5
8 14 5
Lindane C H Cl 58-89-9 290,8 7 6 8
6 6 6
Terbutylazine C H ClN 5915-41-3 229,7 8 7 6
9 16 5
Metribuzine C H NOS 21087-64-9 214,3 9 8 14
8 14 4
Parathion-methyl C H NOPS 298-00-0 263,2 10 9 11
8 10 5
Heptachlor C H Cl 76-44-8 373,3 11 10 9
10 5 7
Terbutryn C H NS 886-50-0 241,4 12 11 12
10 19 5
Aldrin C H Cl 309-00-2 364,9 13 12 10
12 8 6
Metolachlor C H ClNO 51218-45-2 283,8 14 13 13
15 22 2
Parathion-ethyl C H NOPS 56-38-2 291,3 15 14 15
10 14 5
exo-Heptachlorepoxide C H ClO 1024-57-3 389,3 16 16 16
10 5 7
Pendimethalin C H N O 40487-42-1 281,3 17 15 17
13 19 3 4
endo-Heptachlorepoxide C H ClO 28044-83-9 389,3 18 17 18
10 5 7
Triclosan C H Cl O 3380-34-5 289,5 19 18 19
12 7 3 2
Dieldrin C H ClO 60-57-1 380,9 20 19 20
12 8 6
Carfentrazone-ethyl C H Cl F N O 128639-02-1 412,2 21 20 21
15 14 2 3 3 3
Diflufenican C H F N O 83164-33-4 394,3 22 21 22
19 11 5 2 2
Mefenpyr-diethyl C H Cl N O 135590-91-9 373,2 23 22 23
16 18 2 2 4
4 Interferences
4.1 Interferences during sampling
To avoid interference, collect samples as specified in Clause 7, observing the instructions specified in
ISO 5667-1 and ISO 5667-3.
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ISO 27108:2010(E)
4.2 Interferences during extraction procedure
Commercially available SPME fibres differ frequently in quality. Variations in the selectivity of the materials
also frequently occur from batch to batch, thus possibly causing significant deviations in extraction yield. This
does not basically impair their suitability, apart from a resulting higher detection limit of individual substances.
Inadequately conditioned fibres frequently result in lower extraction yields and poorly reproducible results;
therefore precondition new fibres according to Clause 8. Also condition used fibres by performing the whole
SPME process using at least two sampling vials containing only water (5.1) prior to starting with the first
sample of a new sample sequence.
Sensitivity of fibres gradually decreases throughout a sequence of samples. Therefore regular measurements
of the reference solution within the sample sequence (see 9.1) are recommended. The fibre is still usable if
the method shows required sensitivity for substances under investigation.
Adding sodium chloride to the sample results in a clear improvement of the extraction yield for most
substances listed in Table 1. The addition of common salt (near saturation) is therefore recommended. Some
substances listed in Table 1 show a reverse effect, which in most cases is weaker. Salt additions of < 20 % of
the saturation concentration (e.g. about 0,5 g of NaCl in an 8 ml water sample) cause a deterioration in
reproducibility. It is important to keep to exactly the same salt additions for all samples of a calibration
sequence and/or sample sequence.
Salt deposits may accumulate in the metal syringe needle of the fibre holder after extended use. Salt deposits
always occur when the syringe needle of the fibre holder is immersed in the water sample during extraction.
This may damage the fibres and the injector liner. Therefore adjust the immersion depth precisely, and, if
necessary, rinse out the SPME syringe needle to dissolve any encrusted salt.
To ensure that the measurements are of high accuracy and precision, keep extraction time constant (e.g.
60 min) within a sample sequence for all samples. It is highly preferable to use an automatic sampler with an
SPME option.
For automatic operation, preferably use sampling vials with a thin septum (e.g. 0,9 mm to 1,3 mm thickness)
in order to avoid any mechanical problems when piercing the septum of the sample vial with the metal syringe
needle.
NOTE This is of particular importance when using automatic sampler systems that move sample vials in a circle,
because otherwise damage to the piercing metal syringe needle (including the exposed fibre) can occur during extraction.
Extraction of some of the substances listed in Table 1 using the procedure according to Clause 8 depends on
the temperature. As a rule, somewhat higher extraction yields are obtained at lower temperatures. Maintain
extraction temperature constant (e.g. 30 °C) within a sample sequence for all samples in order to obtain
reproducible extraction yields.
4.3 Interferences during gas chromatography and mass spectrometry procedure
Interferences may be caused, e.g. by the injection system used or by inadequate separation of the analytes.
Experienced operators, using the information given in the instrument manuals, may be able to minimise this
type of interference. Regular checking of the chromatographic and spectrometric system is required to
maintain adequate performance. Required system stability should be checked regularly by the use of a
GC standard.
Ascertain the necessary penetration depth for the fibres for thermal desorption in the GC injector. The
penetration depth corresponds to the hottest point of the injector and shall be kept constant during a
measuring sequence.
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ISO 27108:2010(E)
5 Reagents
The reagents shall be free from impurities possibly interfering with the GC-MS analysis.
Use solvents and reagents of sufficient purity, i.e. with negligibly low impurities compared with the
concentration of analytes to be determined. As reagents, use, as far as available, “residual grade” or better in
order to obtain low blanks. Verify by blank determinations and, if necessary, apply additional cleaning steps.
5.1 Water, complying with the requirements of ISO 3696, grade 1 or equivalent.
5.2 Operating gases for the gas chromatograph-mass spectrometer, of high purity and in accordance
with manufacturer's specifications.
5.3 Sodium chloride, NaCl.
5.4 Solvents, e.g. ethyl acetate, C H O ; acetone (propanone), C H O; acetonitrile, CH CN.
4 8 2 3 6 3
For the preparation of stock solutions of individual reference substances (5.9.2) use the appropriate solvent.
However, it is recommended to prepare multi-component stock solutions (5.9.3) using either acetone or ethyl
acetate.
5.5 Sodium hydroxide solution, w(NaOH) = 25 % mass fraction.
5.6 Hydrochloric acid, w(HCl) = 25 % mass fraction or sulfuric acid, w(H SO ) = 12,5 % mass fraction.
2 4
5.7 Sodium thiosulfate pentahydrate, Na S O ·5 H O.
2 2 3 2
5.8 Internal standard, e.g. atrazine-d , lindane-d or parathion-ethyl-d .
5 6 10
As internal standard, choose a substance with similar physicochemical properties (extraction behaviour,
retention time) as the substance to be determined. The internal standard should not be present in the sample
to be analysed. The choice of a substance may be difficult and it depends on the problem to be resolved; in
any case, the suitability should be checked. It is highly recommended to use a deuterium-labelled or
13
C-enriched substance listed in Table 1 as an internal standard. It may be advantageous to use more than
one internal standard.
Prepare stock solutions of individual internal standard substances in the same way as specified for individual
reference substances (5.9.2).
5.9 Reference substances
5.9.1 General
Reference substances (listed in Table 1) of defined concentration suitable for both the preparation of stock
solutions and the preparation of spiked aqueous multi-component reference solutions used for calibration of
the total procedure (9.2).
5.9.2 Stock solutions of individual reference substances
As an example, place 50 mg of a reference substance into a 100 ml one-mark volumetric flask (6.6), dissolve
in an appropriate solvent (5.4) and make up to the mark with the same solvent.
Store stock solutions at temperatures between 1 °C and 5 °C according to ISO 5667-3, protected from light.
They are stable for at least 12 months.
NOTE Deep freezing of stock solutions is also possible and commonly applied.
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ISO 27108:2010(E)
5.9.3 Multi-component stock solutions of reference substances
As an example, transfer 1 ml of each of the solutions of the individual substances (5.9.2) and the internal
standard substances (5.8) into a 100 ml one-mark volumetric flask (6.6) and make up to the mark with ethyl
acetate or acetone (5.4).
Store multi-component stock solutions at temperatures between 1 °C and 5 °C, protected from light. They are
stable for at least 6 months.
5.9.4 Aqueous multi-component reference solutions used for calibration of the total procedure
Prepare the aqueous reference solution for calibration of the total procedure as follows.
Measure 100 ml of water, e.g. in a one-mark volumetric flask (6.6) and add a magnetic stir bar.
Place the flask on a magnetic stirrer and switch on.
Using a microlitre syringe, measure 10 µl of the multi-component stock solution (5.9.3) and dispense it below
the surface of the stirred water. Continue to stir for about 5 min with the volumetric flask covered.
Adjust the agitation speed so that no turbulence funnel is formed.
Prepare reference solutions of higher and lower concentrations in the same way using correspondingly
prepared multi-component stock solutions (5.9.3). All aqueous reference solutions suitable for multipoint
calibration should contain equal amounts of internal standard.
Do not dilute the spiked aqueous solutions.
Always keep the spike volume constant.
NOTE A small spiking volume (e.g. 10 µl in 100 ml water) is recommended to avoid any interference of the solvent
within the fibre adsorption process of the analytes under investigation.
Store reference solutions at temperatures between 1 °C and 5 °C, protected from light. They may not be
stable for more than a few days and therefore shall be prepared each working day.
6 Apparatus
Equipment or parts of it which are likely to come into contact with the water sample or its extract shall be free
from residues causing interferences. The use of vessels made of glass, stainless steel or
polytetrafluoroethylene (PTFE) is recommended.
Usual laboratory equipment and in particular the following.
6.1 Sample flasks, e.g. brown glass, flat bottomed, with glass- or PTFE-coated stoppers, e.g. 100 ml or
250 ml.
6.2 Glass sample bottles (head space vials), with caps (6.3), e.g. 10 ml or 20 ml.
6.3 Crimp caps, with PTFE-coated septa (e.g. magnetic caps with butyl/PTFE septa, 0,9 mm to 1,3 mm).
NOTE Commercially available head space vials usually have a flanged rim suitable for a 3 mm septum. A thinner
septum (e.g. 0,9 mm to 1,1 mm) requires suitable vials with a thicker flanged rim. Alternatively, a perforated spacer ring
(e.g. made of natural rubber or butyl, 1,3 mm thick) can be placed between septum and crimp cap.
6.4 Crimper and decapper (e.g. manual crimper and manual decapper, 20 mm).
[3]
6.5 Graduated measuring cylinders, capacity, e.g. 100 ml or 250 ml, ISO 4788 class A.
[2]
6.6 One-mark volumetric flasks, capacity, e.g. 10 ml, 25 ml, 50 ml and 100 ml, ISO 1042 class A.
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ISO 27108:2010(E)
[1]
6.7 Single volume pipettes, capacities between 1 ml and 50 ml, ISO 648 class A.
6.8 Microlitre syringes, e.g. capacities between 5 µl and 50 µl.
6.9 Magnetic stirrer, including PTFE-coated magnetic stir bar of suitable size.
6.10 Capillary gas chromatograph with mass spectrometric detector (GC-MS) using EI ionisation mode,
gas supply in accordance with the respective manufacturer's instructions.
6.11 Non-discriminating GC injector, e.g. splitless mode of a split or splitless injection system or
programmable temperature vaporiser (PTV).
6.12 Automatic sampler with SPME option, including SPME syringe and the necessary software.
6.13 SPME fibres, e.g. 10 mm medium polar polyacrylate-phases (PA coating: e.g. 85 µm) or bipolar
polydimethylsiloxane/divinylbenzene phases (PDMS/DVB coating: e.g. 65 µm). Other fibres as mentioned
above may be applicable as well. However, it is necessary to verify their sensitivity for the substances under
investigation (see 9.1).
NOTE Polyacrylate phases (PA 85) have proved to be most sensitive for the substances listed in Table 1.
Preferably use 23-gauge needles (particularly in combination with a septumless GC inlet system). If using a
septum type injection system, 24-gauge needles should be used to reduce septum coring.
6.14 Capillary columns, for gas chromatography (examples of chromatographs appear in Annex A). It is
advantageous to use non-polar columns (e.g. low-bleed 5 %-phenylsiloxane column).
6.15 Borosilicate glass fibre filter, fibre diameter of 0,75 µm to 1,5 µm, with inorganic binding material.
6.16 Centrifuge, e.g. capable of reaching 2 000 r/min with appropriate centrifuge tubes.
6.17 pH meter, with electrodes.
7 Sampling and sample pretreatment
Collect samples as specified in ISO 5667-1 and ISO 5667-3.
For sampling, use thoroughly cleaned, flat bottomed glass flasks (6.1). Rinse flasks and caps with the water to
be sampled.
Fill the bottles completely with the water to be examined.
Dechlorinate water samples containing chlorine by immediately adding sodium thiosulfate pentahydrate (5.7),
resulting in a concentration of approximately 100 mg/l.
Treat and analyse the samples as soon as possible after sample collection as specified in ISO 5667-3. Store
the samples at temperatures between 1 °C and 5 °C, protected from light.
8 Procedure
8.1 Sample preparation and extraction
Remove any suspended matter by, for example, filtration of the sample through a glass fibre filter (6.15) or
centrifugation (6.16) to remove suspended matter.
NOTE Filtration or centrifugation of drinking water samples is not mandatory.
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ISO 27108:2010(E)
The pH value of the water sample only requires adjustment if it is below 6 ± 0,2 or above 8 ± 0,2. In this case,
adjust to pH 7 ± 0,2 with hydrochloric acid (5.6), sulfuric acid (5.6) or sodium hydroxide solution (5.5).
Add the internal standard (5.8) dissolved in ethyl acetate or acetone (5.4) (e.g. by adding a 10 µl aliquot to a
100 ml sample volume as described in 5.9.4).
For example, measure exactly 8 ml (or 16 ml) of the water sample being examined and pour into a 10 ml (or
20 ml) head space vial (6.2). The measured volume shall be equal for both calibration and sample
measurement.
Choose the sample volume so that there is a distance of 15 mm to 25 mm between the level of the liquid and
the upper edge of the vial.
CAUTION — This is particularly important in automatic systems which rotate the sample vials,
causing rotation of the metal syringe needle (including the exposed fibre) during extraction to avoid
any mechanical problems (broken fibre or broken needle). Take note of the information given in 4.2,
paragraph 6.
Add sodium chloride (5.3) near saturation point, i.e. 0,3 g per millilitre of sample volume (e.g. 2,4 g NaCl in
8 ml water) and dissolve. Avoid concentrations of NaCl higher than 0,35 g/ml. Close with a septum fitted crimp
cap (6.3) using a crimper (6.4). Place the vials in sampling sequence on the automatic sampler with SPME
option (6.13).
Use SPME fibres (6.13).
Condition new fibres by heating them up in the “bake-out” station of the SPME automatic sampler or in the
injector of the GC. Refer to the manufacturer's instructions for appropriate fibre bake-out times. Proceed with
at least two sampling vials containing only water (5.1) within a new sample sequence prior to starting with the
first sample. Recalibration is needed when a new fibre is installed.
Adjust the extraction temperature to approximately 30 °C (see 4.2). Maintain extraction temperature constant
within a sample sequence for all samples in order to obtain reproducible extraction yields.
−1
Set the agitation speed to a maximum reproducible value (e.g. 250 min ). In systems using a magnetic stirrer,
pierce the septum approx. 3 mm from the middle.
Extraction time should be set to 60 min.
NOTE An extraction time of 60 min produces acceptable sensitivity for all substances listed in Table 1. However,
depending on sensitivity requirements, shorter extraction times are possible.
Desorb in the injector for 10 min at 280 °C.
8.2 Gas chromatograph
Check the required system stability regularly. Adjust and optimise instrument parameter settings in
accordance with the respective manufacturer's instructions.
For separation, use appropriate capillary columns (6.14) and adjust chromatographic conditions for maximum
selectivity (see Annex A for examples).
8.3 Identification of individual compounds by means of GC-MS
Identify the sample component by matching both retention times and relative intensities of the diagnostic ions
(Table 2) of sample components and reference substances (5.9).
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ISO 27108:2010(E)
The target compound is present (is identified) in the sample if:
a) the relative or the absolute sample component retention time measured in the selected ion current
chromatogram matches the relative or absolute retention time of the authentic compound within ± 0,2 %
in the chromatogram of the latest calibration standard solution (e.g. aqueous multi-component reference
solution; see 5.9.4), measured under identical conditions;
b) three selected diagnostic ions (see Table 2) are present at the substance-specific retention time;
c) relative intensities of all selected diagnostic ions measured in the sample do not deviate by more than
± (0,1l + 10) % from the relative intensities determined in the calibration standard solution, where I is the
relative intensity of the diagnostic ion of the individual reference substance.
EXAMPLE
Three selected diagnostic ions have the following relative intensities: 100 %, 50 % and 15 %.
The maximum allowed deviation in the sample is:
a) ± (0,1 l x 100 + 10) % = ± 20 %; relative intensity in the sample shall lie within 80 % and 120 %;
b) ± (0,1 l x 50 + 10) % = ± 15 %; relative intensity in the sample shall lie between 35 % and 65 %;
c) ± (0,1 l x 15 + 10) % = ± 11,5 %; relative intensity in the sample shall lie between 3,5 % and 26,5 %.
NOTE 1 No ion of significant intensity should be present in the mass spectrum after background subtraction with a
larger mass than the highest possible mass for a compound to be identified.
[6]
NOTE 2 Furt
...
SLOVENSKI STANDARD
SIST ISO 27108:2011
01-junij-2011
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0HWRGDSOLQVNHNURPDWRJUDILMHPDVQHVSHNWURPHWULMH *&06 SRPLNURHNVWUDNFLML
QDWUGQLID]L 630(
Water quality - Determination of selected plant treatment agents and biocide products -
Method using solid-phase microextraction (SPME) followed by gas chromatography-
mass spectrometry (GC-MS)
Qualité de l'eau - Détermination d'agents de traitement et de produits d'usine
sélectionnés - Méthode utilisant une micro-extraction en phase solide (MEPS) suivie
d'une chromatographie en phase gazeuse-spectrométrie de masse (CG-SM)
Ta slovenski standard je istoveten z: ISO 27108:2010
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
SIST ISO 27108:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 27108:2011
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SIST ISO 27108:2011
INTERNATIONAL ISO
STANDARD 27108
First edition
2010-04-15
Water quality — Determination of
selected plant treatment agents and
biocide products — Method using solid-
phase microextraction (SPME) followed
by gas chromatography-mass
spectrometry (GC-MS)
Qualité de l'eau — Détermination d'agents de traitement et de produits
d'usine sélectionnés — Méthode utilisant une micro-extraction en phase
solide (MEPS) suivie d'une chromatographie en phase gazeuse-
spectrométrie de masse (CG-SM)
Reference number
ISO 27108:2010(E)
©
ISO 2010
---------------------- Page: 3 ----------------------
SIST ISO 27108:2011
ISO 27108:2010(E)
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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
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Published in Switzerland
ii © ISO 2010 – All rights reserved
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SIST ISO 27108:2011
ISO 27108:2010(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Principle.1
4 Interferences .2
5 Reagents.4
6 Apparatus.5
7 Sampling and sample pretreatment .6
8 Procedure.6
9 Calibration.8
10 Calculation .11
11 Expression of results.11
12 Test report.11
Annex A (informative) Examples of gas chromatograms for compounds listed in Table 1 .12
Annex B (informative) Mass spectra of compounds of Table 1 (full-scan, EI, 70 eV).21
Annex C (informative) Precision data .35
Annex D (informative) General information about SPME .36
Bibliography.37
© ISO 2010 – All rights reserved iii
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SIST ISO 27108:2011
ISO 27108:2010(E)
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 27108 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
iv © ISO 2010 – All rights reserved
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SIST ISO 27108:2011
ISO 27108:2010(E)
Introduction
In recent years, ground water contamination as well as surface water contamination by pesticides has become
a matter of public concern. Identification and quantification of pesticides at trace level concentrations often
require both high sensitive chromatographic equipment and effective enrichment steps. In the analysis of
aqueous samples, sample preparation techniques including solid-phase extraction (SPE) are frequently the
most time-consuming steps and in many cases can be effectively replaced by solid-phase microextraction
(SPME).
When using this International Standard, it may be necessary in some cases to determine whether and to what
extent particular problems could require the specification of additional marginal conditions.
© ISO 2010 – All rights reserved v
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SIST ISO 27108:2011
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SIST ISO 27108:2011
INTERNATIONAL STANDARD ISO 27108:2010(E)
Water quality — Determination of selected plant treatment
agents and biocide products — Method using solid-phase
microextraction (SPME) followed by gas chromatography-mass
spectrometry (GC-MS)
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This International Standard does not purport to address all of the safety problems, if any,
associated with its use. It is the responsibility of the user 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 International Standard
be carried out by suitably trained staff.
1 Scope
This International Standard specifies a method for the determination of the dissolved amount of selected plant
treatment agents and biocide products in drinking water, ground water and surface water by solid-phase
microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS). The limit of
determination depends on the matrix, on the specific compound to be analysed and on the sensitivity of the
mass spectrometer. For most plant treatment agents and biocides to which this International Standard applies,
it is at least 0,05 µg/l. Validation data related to a concentration range between 0,05 µg/l and 0,3 µg/l have
been demonstrated in an interlaboratory trial.
This method may be applicable to other compounds not explicitly covered by this International Standard or to
other types of water. However, it is necessary to verify the applicability of this method for these special cases.
NOTE Determinations by this International Standard are performed on small sample amounts (e.g. sample volumes
between 8 ml and 16 ml).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5667-1, Water quality — Sampling — Part 1: Guidance on the design of sampling programmes and
sampling techniques
ISO 5667-3, Water quality — Sampling — Part 3: Guidance on the preservation and handling of water
samples
3 Principle
Substances under investigation are extracted from the water sample by solid-phase microextraction (SPME)
according to their equilibrium of distribution. The extraction is performed by a chemically modified fused-silica
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ISO 27108:2010(E)
fibre, the surface of which is coated with a suitable adsorbent polymer. During extraction, the fibre is
immersed in the liquid sample. After completion of the extraction procedure, the fibre is drawn back into the
needle, removed from the sample vial, and introduced directly into the GC injector. The analytes are
transferred to the GC column by thermal desorption.
The analytes are separated, identified and quantified by means of capillary gas chromatography with mass
spectrometric detection (GC-MS) using electron impact (EI) ionisation mode.
Table 1 — Plant treatment agents and biocide products determined by this method
Reference No. in example
Molar mass
chromatograms of Figure
Name Molecular formula CAS registry No.
g/mol A.1 A.2 A.3
Dichlobenil C H ClN 1194-65-6 172,0 1 1 1
7 3 2
Desethylatrazine C H ClN 6190-65-4 187,6 2 2 3
6 10 5
Desethylterbutylazine C H ClN 30125-63-4 201,7 3 3 2
7 12 5
Simazine C H ClN 122-34-9 201,7 4 4 7
7 12 5
Atrazine C H ClN 1912-24-9 215,7 6 5 5
8 14 5
Lindane C H Cl 58-89-9 290,8 7 6 8
6 6 6
Terbutylazine C H ClN 5915-41-3 229,7 8 7 6
9 16 5
Metribuzine C H NOS 21087-64-9 214,3 9 8 14
8 14 4
Parathion-methyl C H NOPS 298-00-0 263,2 10 9 11
8 10 5
Heptachlor C H Cl 76-44-8 373,3 11 10 9
10 5 7
Terbutryn C H NS 886-50-0 241,4 12 11 12
10 19 5
Aldrin C H Cl 309-00-2 364,9 13 12 10
12 8 6
Metolachlor C H ClNO 51218-45-2 283,8 14 13 13
15 22 2
Parathion-ethyl C H NOPS 56-38-2 291,3 15 14 15
10 14 5
exo-Heptachlorepoxide C H ClO 1024-57-3 389,3 16 16 16
10 5 7
Pendimethalin C H N O 40487-42-1 281,3 17 15 17
13 19 3 4
endo-Heptachlorepoxide C H ClO 28044-83-9 389,3 18 17 18
10 5 7
Triclosan C H Cl O 3380-34-5 289,5 19 18 19
12 7 3 2
Dieldrin C H ClO 60-57-1 380,9 20 19 20
12 8 6
Carfentrazone-ethyl C H Cl F N O 128639-02-1 412,2 21 20 21
15 14 2 3 3 3
Diflufenican C H F N O 83164-33-4 394,3 22 21 22
19 11 5 2 2
Mefenpyr-diethyl C H Cl N O 135590-91-9 373,2 23 22 23
16 18 2 2 4
4 Interferences
4.1 Interferences during sampling
To avoid interference, collect samples as specified in Clause 7, observing the instructions specified in
ISO 5667-1 and ISO 5667-3.
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4.2 Interferences during extraction procedure
Commercially available SPME fibres differ frequently in quality. Variations in the selectivity of the materials
also frequently occur from batch to batch, thus possibly causing significant deviations in extraction yield. This
does not basically impair their suitability, apart from a resulting higher detection limit of individual substances.
Inadequately conditioned fibres frequently result in lower extraction yields and poorly reproducible results;
therefore precondition new fibres according to Clause 8. Also condition used fibres by performing the whole
SPME process using at least two sampling vials containing only water (5.1) prior to starting with the first
sample of a new sample sequence.
Sensitivity of fibres gradually decreases throughout a sequence of samples. Therefore regular measurements
of the reference solution within the sample sequence (see 9.1) are recommended. The fibre is still usable if
the method shows required sensitivity for substances under investigation.
Adding sodium chloride to the sample results in a clear improvement of the extraction yield for most
substances listed in Table 1. The addition of common salt (near saturation) is therefore recommended. Some
substances listed in Table 1 show a reverse effect, which in most cases is weaker. Salt additions of < 20 % of
the saturation concentration (e.g. about 0,5 g of NaCl in an 8 ml water sample) cause a deterioration in
reproducibility. It is important to keep to exactly the same salt additions for all samples of a calibration
sequence and/or sample sequence.
Salt deposits may accumulate in the metal syringe needle of the fibre holder after extended use. Salt deposits
always occur when the syringe needle of the fibre holder is immersed in the water sample during extraction.
This may damage the fibres and the injector liner. Therefore adjust the immersion depth precisely, and, if
necessary, rinse out the SPME syringe needle to dissolve any encrusted salt.
To ensure that the measurements are of high accuracy and precision, keep extraction time constant (e.g.
60 min) within a sample sequence for all samples. It is highly preferable to use an automatic sampler with an
SPME option.
For automatic operation, preferably use sampling vials with a thin septum (e.g. 0,9 mm to 1,3 mm thickness)
in order to avoid any mechanical problems when piercing the septum of the sample vial with the metal syringe
needle.
NOTE This is of particular importance when using automatic sampler systems that move sample vials in a circle,
because otherwise damage to the piercing metal syringe needle (including the exposed fibre) can occur during extraction.
Extraction of some of the substances listed in Table 1 using the procedure according to Clause 8 depends on
the temperature. As a rule, somewhat higher extraction yields are obtained at lower temperatures. Maintain
extraction temperature constant (e.g. 30 °C) within a sample sequence for all samples in order to obtain
reproducible extraction yields.
4.3 Interferences during gas chromatography and mass spectrometry procedure
Interferences may be caused, e.g. by the injection system used or by inadequate separation of the analytes.
Experienced operators, using the information given in the instrument manuals, may be able to minimise this
type of interference. Regular checking of the chromatographic and spectrometric system is required to
maintain adequate performance. Required system stability should be checked regularly by the use of a
GC standard.
Ascertain the necessary penetration depth for the fibres for thermal desorption in the GC injector. The
penetration depth corresponds to the hottest point of the injector and shall be kept constant during a
measuring sequence.
© ISO 2010 – All rights reserved 3
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SIST ISO 27108:2011
ISO 27108:2010(E)
5 Reagents
The reagents shall be free from impurities possibly interfering with the GC-MS analysis.
Use solvents and reagents of sufficient purity, i.e. with negligibly low impurities compared with the
concentration of analytes to be determined. As reagents, use, as far as available, “residual grade” or better in
order to obtain low blanks. Verify by blank determinations and, if necessary, apply additional cleaning steps.
5.1 Water, complying with the requirements of ISO 3696, grade 1 or equivalent.
5.2 Operating gases for the gas chromatograph-mass spectrometer, of high purity and in accordance
with manufacturer's specifications.
5.3 Sodium chloride, NaCl.
5.4 Solvents, e.g. ethyl acetate, C H O ; acetone (propanone), C H O; acetonitrile, CH CN.
4 8 2 3 6 3
For the preparation of stock solutions of individual reference substances (5.9.2) use the appropriate solvent.
However, it is recommended to prepare multi-component stock solutions (5.9.3) using either acetone or ethyl
acetate.
5.5 Sodium hydroxide solution, w(NaOH) = 25 % mass fraction.
5.6 Hydrochloric acid, w(HCl) = 25 % mass fraction or sulfuric acid, w(H SO ) = 12,5 % mass fraction.
2 4
5.7 Sodium thiosulfate pentahydrate, Na S O ·5 H O.
2 2 3 2
5.8 Internal standard, e.g. atrazine-d , lindane-d or parathion-ethyl-d .
5 6 10
As internal standard, choose a substance with similar physicochemical properties (extraction behaviour,
retention time) as the substance to be determined. The internal standard should not be present in the sample
to be analysed. The choice of a substance may be difficult and it depends on the problem to be resolved; in
any case, the suitability should be checked. It is highly recommended to use a deuterium-labelled or
13
C-enriched substance listed in Table 1 as an internal standard. It may be advantageous to use more than
one internal standard.
Prepare stock solutions of individual internal standard substances in the same way as specified for individual
reference substances (5.9.2).
5.9 Reference substances
5.9.1 General
Reference substances (listed in Table 1) of defined concentration suitable for both the preparation of stock
solutions and the preparation of spiked aqueous multi-component reference solutions used for calibration of
the total procedure (9.2).
5.9.2 Stock solutions of individual reference substances
As an example, place 50 mg of a reference substance into a 100 ml one-mark volumetric flask (6.6), dissolve
in an appropriate solvent (5.4) and make up to the mark with the same solvent.
Store stock solutions at temperatures between 1 °C and 5 °C according to ISO 5667-3, protected from light.
They are stable for at least 12 months.
NOTE Deep freezing of stock solutions is also possible and commonly applied.
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5.9.3 Multi-component stock solutions of reference substances
As an example, transfer 1 ml of each of the solutions of the individual substances (5.9.2) and the internal
standard substances (5.8) into a 100 ml one-mark volumetric flask (6.6) and make up to the mark with ethyl
acetate or acetone (5.4).
Store multi-component stock solutions at temperatures between 1 °C and 5 °C, protected from light. They are
stable for at least 6 months.
5.9.4 Aqueous multi-component reference solutions used for calibration of the total procedure
Prepare the aqueous reference solution for calibration of the total procedure as follows.
Measure 100 ml of water, e.g. in a one-mark volumetric flask (6.6) and add a magnetic stir bar.
Place the flask on a magnetic stirrer and switch on.
Using a microlitre syringe, measure 10 µl of the multi-component stock solution (5.9.3) and dispense it below
the surface of the stirred water. Continue to stir for about 5 min with the volumetric flask covered.
Adjust the agitation speed so that no turbulence funnel is formed.
Prepare reference solutions of higher and lower concentrations in the same way using correspondingly
prepared multi-component stock solutions (5.9.3). All aqueous reference solutions suitable for multipoint
calibration should contain equal amounts of internal standard.
Do not dilute the spiked aqueous solutions.
Always keep the spike volume constant.
NOTE A small spiking volume (e.g. 10 µl in 100 ml water) is recommended to avoid any interference of the solvent
within the fibre adsorption process of the analytes under investigation.
Store reference solutions at temperatures between 1 °C and 5 °C, protected from light. They may not be
stable for more than a few days and therefore shall be prepared each working day.
6 Apparatus
Equipment or parts of it which are likely to come into contact with the water sample or its extract shall be free
from residues causing interferences. The use of vessels made of glass, stainless steel or
polytetrafluoroethylene (PTFE) is recommended.
Usual laboratory equipment and in particular the following.
6.1 Sample flasks, e.g. brown glass, flat bottomed, with glass- or PTFE-coated stoppers, e.g. 100 ml or
250 ml.
6.2 Glass sample bottles (head space vials), with caps (6.3), e.g. 10 ml or 20 ml.
6.3 Crimp caps, with PTFE-coated septa (e.g. magnetic caps with butyl/PTFE septa, 0,9 mm to 1,3 mm).
NOTE Commercially available head space vials usually have a flanged rim suitable for a 3 mm septum. A thinner
septum (e.g. 0,9 mm to 1,1 mm) requires suitable vials with a thicker flanged rim. Alternatively, a perforated spacer ring
(e.g. made of natural rubber or butyl, 1,3 mm thick) can be placed between septum and crimp cap.
6.4 Crimper and decapper (e.g. manual crimper and manual decapper, 20 mm).
[3]
6.5 Graduated measuring cylinders, capacity, e.g. 100 ml or 250 ml, ISO 4788 class A.
[2]
6.6 One-mark volumetric flasks, capacity, e.g. 10 ml, 25 ml, 50 ml and 100 ml, ISO 1042 class A.
© ISO 2010 – All rights reserved 5
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SIST ISO 27108:2011
ISO 27108:2010(E)
[1]
6.7 Single volume pipettes, capacities between 1 ml and 50 ml, ISO 648 class A.
6.8 Microlitre syringes, e.g. capacities between 5 µl and 50 µl.
6.9 Magnetic stirrer, including PTFE-coated magnetic stir bar of suitable size.
6.10 Capillary gas chromatograph with mass spectrometric detector (GC-MS) using EI ionisation mode,
gas supply in accordance with the respective manufacturer's instructions.
6.11 Non-discriminating GC injector, e.g. splitless mode of a split or splitless injection system or
programmable temperature vaporiser (PTV).
6.12 Automatic sampler with SPME option, including SPME syringe and the necessary software.
6.13 SPME fibres, e.g. 10 mm medium polar polyacrylate-phases (PA coating: e.g. 85 µm) or bipolar
polydimethylsiloxane/divinylbenzene phases (PDMS/DVB coating: e.g. 65 µm). Other fibres as mentioned
above may be applicable as well. However, it is necessary to verify their sensitivity for the substances under
investigation (see 9.1).
NOTE Polyacrylate phases (PA 85) have proved to be most sensitive for the substances listed in Table 1.
Preferably use 23-gauge needles (particularly in combination with a septumless GC inlet system). If using a
septum type injection system, 24-gauge needles should be used to reduce septum coring.
6.14 Capillary columns, for gas chromatography (examples of chromatographs appear in Annex A). It is
advantageous to use non-polar columns (e.g. low-bleed 5 %-phenylsiloxane column).
6.15 Borosilicate glass fibre filter, fibre diameter of 0,75 µm to 1,5 µm, with inorganic binding material.
6.16 Centrifuge, e.g. capable of reaching 2 000 r/min with appropriate centrifuge tubes.
6.17 pH meter, with electrodes.
7 Sampling and sample pretreatment
Collect samples as specified in ISO 5667-1 and ISO 5667-3.
For sampling, use thoroughly cleaned, flat bottomed glass flasks (6.1). Rinse flasks and caps with the water to
be sampled.
Fill the bottles completely with the water to be examined.
Dechlorinate water samples containing chlorine by immediately adding sodium thiosulfate pentahydrate (5.7),
resulting in a concentration of approximately 100 mg/l.
Treat and analyse the samples as soon as possible after sample collection as specified in ISO 5667-3. Store
the samples at temperatures between 1 °C and 5 °C, protected from light.
8 Procedure
8.1 Sample preparation and extraction
Remove any suspended matter by, for example, filtration of the sample through a glass fibre filter (6.15) or
centrifugation (6.16) to remove suspended matter.
NOTE Filtration or centrifugation of drinking water samples is not mandatory.
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The pH value of the water sample only requires adjustment if it is below 6 ± 0,2 or above 8 ± 0,2. In this case,
adjust to pH 7 ± 0,2 with hydrochloric acid (5.6), sulfuric acid (5.6) or sodium hydroxide solution (5.5).
Add the internal standard (5.8) dissolved in ethyl acetate or acetone (5.4) (e.g. by adding a 10 µl aliquot to a
100 ml sample volume as described in 5.9.4).
For example, measure exactly 8 ml (or 16 ml) of the water sample being examined and pour into a 10 ml (or
20 ml) head space vial (6.2). The measured volume shall be equal for both calibration and sample
measurement.
Choose the sample volume so that there is a distance of 15 mm to 25 mm between the level of the liquid and
the upper edge of the vial.
CAUTION — This is particularly important in automatic systems which rotate the sample vials,
causing rotation of the metal syringe needle (including the exposed fibre) during extraction to avoid
any mechanical problems (broken fibre or broken needle). Take note of the information given in 4.2,
paragraph 6.
Add sodium chloride (5.3) near saturation point, i.e. 0,3 g per millilitre of sample volume (e.g. 2,4 g NaCl in
8 ml water) and dissolve. Avoid concentrations of NaCl higher than 0,35 g/ml. Close with a septum fitted crimp
cap (6.3) using a crimper (6.4). Place the vials in sampling sequence on the automatic sampler with SPME
option (6.13).
Use SPME fibres (6.13).
Condition new fibres by heating them up in the “bake-out” station of the SPME automatic sampler or in the
injector of the GC. Refer to the manufacturer's instructions for appropriate fibre bake-out times. Proceed with
at least two sampling vials containing only water (5.1) within a new sample sequence prior to starting with the
first sample. Recalibration is needed when a new fibre is installed.
Adjust the extraction temperature to approximately 30 °C (see 4.2). Maintain extraction temperature constant
within a sample sequence for all samples in order to obtain reproducible extraction yields.
−1
Set the agitation speed to a maximum reproducible value (e.g. 250 min ). In systems using a magnetic stirrer,
pierce the septum approx. 3 mm from the middle.
Extraction time should be set to 60 min.
NOTE An extraction time of 60 min produces acceptable sensitivity for all substances listed in Table 1. However,
depending on sensitivity requirements, shorter extraction times are possible.
Desorb in the injector for 10 min at 280 °C.
8.2 Gas chromatograph
Check the required system stability regularly. Adjust and optimise instrument parameter settings in
accordance with the respective manufacturer's instructions.
For separation, use appropriate capillary columns (6.14) and adjust chromatographic conditions for maximum
selectivity (see Annex A for examples).
8.3 Identification of individual compounds by means of GC-MS
Identify the sample component by matching both retention times and relative intensities of the diagnostic ions
(Table 2) of sample components and reference substances (5.9).
© ISO 2010 – All rights reserved 7
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The target compound is present (is identified) in the sample if
...
NORME ISO
INTERNATIONALE 27108
Première édition
2010-04-15
Qualité de l’eau — Détermination
d’agents de traitement et de produits
d’usine sélectionnés — Méthode
utilisant une micro-extraction en
phase solide (MEPS) suivie d’une
chromatographie en phase gazeuse-
spectrométrie de masse (CG-SM)
Water quality — Determination of selected plant treatment agents
and biocide products — Method using solid-phase microextraction
(SPME) followed by gas chromatography-mass spectrometry (GC-MS)
Numéro de référence
ISO 27108:2010(F)
©
ISO 2010
---------------------- Page: 1 ----------------------
ISO 27108:2010(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2010
Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni utilisée
sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie, l’affichage sur
l’internet ou sur un Intranet, sans autorisation écrite préalable. Les demandes d’autorisation peuvent être adressées à l’ISO à
l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Version française parue en 2013
Publié en Suisse
ii © ISO 2010 – Tous droits réservés
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ISO 27108:2010(F)
Sommaire Page
Avant-propos .iv
Introduction .v
1 Domaine d’application . 1
2 Références normatives . 1
3 Principe . 1
4 Interférences . 2
4.1 Interférences lors de l’échantillonnage . 2
4.2 Interférences lors du mode opératoire d’extraction . 2
4.3 Interférences lors du mode opératoire de chromatographie en phase gazeuse et
spectrométrie de masse . 3
5 Réactifs . 4
6 Appareillage . 6
7 Échantillonnage et prétraitement de l’échantillon . 7
8 Mode opératoire. 7
8.1 Préparation des échantillons et extraction . 7
8.2 Chromatographe en phase gazeuse . 8
8.3 Identification des composés individuels par CG-SM . 8
8.4 Mesurage des valeurs à blanc . 9
9 Étalonnage . 9
9.1 Exigences générales . 9
9.2 Étalonnage avec un étalon interne couvrant le mode opératoire total .10
10 Calcul .11
11 Expression des résultats.12
12 Rapport d’essai .12
Annexe A (informative) Exemples de chromatogrammes en phase gazeuse pour les composés
énumérés dans le Tableau 1 .13
Annexe B (informative) Spectres de masse des composés du Tableau 1 (balayage complet, impact
électronique, 70 eV) .23
Annexe C (informative) Données de fidélité .36
Annexe D (informative) Informations générales sur la micro-extraction en phase solide (MEPS) .38
Bibliographie .39
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ISO 27108:2010(F)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.
L’ISO collabore étroitement avec la Commission électrotechnique internationale (CEI) en ce qui concerne
la normalisation électrotechnique.
Les Normes internationales sont rédigées conformément aux règles données dans les Directives
ISO/CEI, Partie 2.
La tâche principale des comités techniques est d’élaborer les Normes internationales. Les projets de
Normes internationales adoptés par les comités techniques sont soumis aux comités membres pour vote.
Leur publication comme Normes internationales requiert l’approbation de 75 % au moins des comités
membres votants.
L’attention est appelée sur le fait que certains des éléments du présent document peuvent faire l’objet de
droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable de
ne pas avoir identifié de tels droits de propriété et averti de leur existence.
L’ISO 27108 a été élaborée par le comité technique ISO/TC 147, Qualité de l’eau, sous-comité SC 2, Méthodes
physiques, chimiques et biochimiques.
iv © ISO 2010 – Tous droits réservés
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ISO 27108:2010(F)
Introduction
Au cours de ces dernières années, la contamination des eaux souterraines et des eaux de surface par
les pesticides est devenue un sujet de préoccupation d’ordre public. L’identification et la quantification
des pesticides à des concentrations présentes à l’état de traces nécessitent souvent des équipements
chromatographiques de grande sensibilité et des étapes d’enrichissement effectives. Dans l’analyse
d’échantillons aqueux, les techniques de préparation des échantillons, y compris l’extraction en phase
solide (EPS), constituent souvent les étapes les plus chronophages et peuvent, dans un grand nombre de
cas, être efficacement remplacées par la micro-extraction en phase solide (MEPS).
Lors de l’utilisation de la présente Norme internationale, il est possible que l’on soit amené, dans certains
cas, à déterminer si et dans quelle mesure des problèmes particuliers nécessiteront la spécification de
conditions particulières.
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NORME INTERNATIONALE ISO 27108:2010(F)
Qualité de l’eau — Détermination d’agents de traitement
et de produits d’usine sélectionnés — Méthode utilisant
une micro-extraction en phase solide (MEPS) suivie d’une
chromatographie en phase gazeuse-spectrométrie de
masse (CG-SM)
AVERTISSEMENT — Il convient que l’utilisateur de la présente Norme internationale connaisse
bien les pratiques courantes de laboratoire. La présente Norme internationale n’a pas pour but
de traiter tous les problèmes de sécurité qui sont, le cas échéant, liés à son utilisation. Il incombe
à l’utilisateur d’établir des pratiques appropriées en matière d’hygiène et de sécurité, et de
s’assurer de la conformité à la réglementation nationale en vigueur.
IMPORTANT — Il est absolument essentiel que les essais réalisés conformément à la présente
Norme internationale soient exécutés par du personnel ayant reçu une formation adéquate.
1 Domaine d’application
La présente Norme internationale spécifie une méthode pour la détermination de la quantité d’agents
de traitement et de produits d’usine sélectionnés dissous dans l’eau potable, les eaux souterraines et
les eaux de surface par micro-extraction en phase solide (MEPS) suivie d’une chromatographie en
phase gazeuse-spectrométrie de masse (CG-SM). La limite de la détermination dépend de la matrice, du
composé spécifique à analyser et de la sensibilité du spectromètre de masse. Pour la plupart des agents
de traitement et de produits d’usine auxquels la présente Norme internationale s’applique, elle est d’au
moins 0,05 µg/l. Les données de validation relatives à une gamme de concentrations comprises entre
0,05 µg/l et 0,3 µg/l ont été démontrées lors d’un essai interlaboratoires.
Cette méthode peut être applicable à d’autres composés qui ne sont pas explicitement traités dans
la présente Norme internationale ou à d’autres types d’eau. Toutefois, il est nécessaire de vérifier
l’applicabilité de cette méthode à ces cas particuliers.
NOTE Les déterminations selon la présente Norme internationale sont effectuées sur des petites quantités
d’échantillon (par exemple, volumes d’échantillon compris entre 8 ml et 16 ml).
2 Références normatives
Les documents suivants, en tout ou partie, sont référencés de manière normative dans le présent
document et sont indispensables pour son application. Pour les références datées, seule l’édition citée
s’applique. Pour les références non datées, la dernière édition du document de référence s’applique (y
compris les éventuels amendements).
ISO 3696, Eau pour laboratoire à usage analytique — Spécification et méthodes d’essai
ISO 5667-1, Qualité de l’eau — Échantillonnage — Partie 1: Lignes directrices pour la conception des
programmes et des techniques d’échantillonnage
ISO 5667-3, Qualité de l’eau — Échantillonnage — Partie 3: Lignes directrices pour la conservation et la
manipulation des échantillons d’eau
3 Principe
Les substances étudiées sont extraites de l’échantillon d’eau par micro-extraction en phase solide (MEPS)
selon leur équilibre de distribution. L’extraction est effectuée par une fibre de silice fondue chimiquement
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ISO 27108:2010(F)
modifiée dont la surface est revêtue d’un adsorbant polymère approprié. Durant l’extraction, la fibre est
immergée dans l’échantillon liquide. À l’issue de la procédure d’extraction, la fibre est ramenée dans
l’aiguille, retirée du flacon à échantillon, puis introduite directement dans l’injecteur du chromatographe
en phase gazeuse. Les analytes sont transférés vers la colonne CG par désorption thermique.
Les analytes sont séparés, identifiés et quantifiés par chromatographie en phase gazeuse sur capillaire
avec détection par spectrométrie de masse (CG-SM) utilisant un mode d’ionisation par impact
électronique.
Tableau 1 — Agents de traitement et produits d’usine déterminés par cette méthode
Numéro de référence dans
Masse
les exemples de chromato-
Formule molécu-
molaire
Nom Numéro CAS
grammes de la Figure
laire
g/mol A.1 A.2 A.3
Dichlobénil C H Cl N 1194-65-6 172,0 1 1 1
7 3 2
Déséthylatrazine C H ClN 6190-65-4 187,6 2 2 3
6 10 5
Déséthylterbuthylazine C H ClN 30125-63-4 201,7 3 3 2
7 12 5
Simazine C H ClN 122-34-9 201,7 4 4 7
7 12 5
Atrazine C H ClN 1912-24-9 215,7 6 5 5
8 14 5
Lindane C H Cl 58-89-9 290,8 7 6 8
6 6 6
Terbuthylazine C H ClN 5915-41-3 229,7 8 7 6
9 16 5
Métribuzine C H N OS 21087-64-9 214,3 9 8 14
8 14 4
Parathion-méthyl C H NO PS 298-00-0 263,2 10 9 11
8 10 5
Heptachlore C H Cl 76-44-8 373,3 11 10 9
10 5 7
Terbutryne C H N S 886-50-0 241,4 12 11 12
10 19 5
Aldrine C H Cl 309-00-2 364,9 13 12 10
12 8 6
Métolachlore C H ClNO 51218-45-2 283,8 14 13 13
15 22 2
Parathion-éthyl C H NO PS 56-38-2 291,3 15 14 15
10 14 5
exo-Heptachlore-époxyde C H Cl O 1024-57-3 389,3 16 16 16
10 5 7
Pendiméthaline C H N O 40487-42-1 281,3 17 15 17
13 19 3 4
endo-Heptachlore-époxyde C H Cl O 28044-83-9 389,3 18 17 18
10 5 7
Triclosan C H Cl O 3380-34-5 289,5 19 18 19
12 7 3 2
Dieldrine C H Cl O 60-57-1 380,9 20 19 20
12 8 6
Carfentrazone-éthyle C H Cl F N O 128639-02-1 412,2 21 20 21
15 14 2 3 3 3
Diflufénican C H F N O 83164-33-4 394,3 22 21 22
19 11 5 2 2
Méfenpyr-diéthyl C H Cl N O 135590-91-9 373,2 23 22 23
16 18 2 2 4
4 Interférences
4.1 Interférences lors de l’échantillonnage
Pour éviter toute interférence, prélever les échantillons comme spécifié à l’Article 7, en observant les
instructions spécifiées dans l’ISO 5667-1 et l’ISO 5667-3.
4.2 Interférences lors du mode opératoire d’extraction
Les fibres de MEPS disponibles dans le commerce présentent souvent des niveaux de qualité différents.
D’un lot à l’autre, on observe également des variations fréquentes de sélectivité des matériaux susceptibles
2 © ISO 2010 – Tous droits réservés
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ISO 27108:2010(F)
d’entraîner des écarts notables de rendement d’extraction. Cela n’altère pas fondamentalement
leur aptitude, hormis le fait qu’elles présentent une limite de détection plus élevée des substances
individuelles.
Des fibres conditionnées de manière inadéquate donnent souvent lieu à des rendements d’extraction plus
faibles et à une mauvaise reproductibilité des résultats; les fibres neuves doivent donc être soumises à
un conditionnement préalable conformément à l’Article 8. Les fibres usagées doivent être également
conditionnées en exécutant la procédure MEPS dans son intégralité en utilisant au moins deux flacons
d’échantillonnage contenant uniquement de l’eau (5.1), avant de commencer avec le premier échantillon
d’une séquence d’analyse de nouveaux échantillons.
La sensibilité des fibres diminue progressivement lors d’une série d’échantillons. Par conséquent, il est
recommandé d’effectuer des mesures régulières de la solution de référence lors de l’analyse de la série
d’échantillons (voir 9.1). La fibre est utilisable tant que la méthode montre que la sensibilité requise est
maintenue pour les substances étudiées.
L’ajout de chlorure de sodium à l’échantillon entraîne une nette amélioration du rendement d’extraction
pour la plupart des substances énumérées dans le Tableau 1. L’ajout de sel courant (à une concentration
proche de la saturation) est donc recommandé. Certaines substances énumérées dans le Tableau 1
montrent un effet inverse qui, dans la majorité des cas, est plus faible. Le fait d’ajouter du sel à des
concentrations inférieures à 20 % de la concentration de saturation (par exemple environ 0,5 g de NaCl
dans un échantillon d’eau de 8 ml) entraîne une détérioration de la reproductibilité. Il est important
d’ajouter exactement la même quantité de sel à tous les échantillons lors d’une séquence d’étalonnage
et/ou d’une séquence d’analyse des échantillons.
Suite à une utilisation prolongée, il est possible que des dépôts de sel s’accumulent dans l’aiguille
métallique de la seringue du support de fibre. Les dépôts de sel se produisent toujours lorsque l’aiguille
de la seringue du support de fibre est immergée dans l’échantillon d’eau au cours de l’extraction. Ces
dépôts peuvent endommager les fibres et le revêtement de l’injecteur. En conséquence, ajuster la
profondeur d’immersion de façon précise et, si nécessaire, rincer abondamment l’aiguille de la seringue
de MEPS pour dissoudre le sel incrusté.
Afin de s’assurer que les mesures sont effectuées avec une exactitude et une fidélité élevées, il est
nécessaire que le temps d’extraction reste constant (par exemple 60 min) au cours d’une séquence
d’analyse pour tous les échantillons. Il est vivement recommandé d’utiliser un dispositif d’échantillonnage
automatique avec une option MEPS.
En cas de fonctionnement automatique, utiliser de préférence des flacons d’échantillonnage avec
un septum mince (par exemple d’une épaisseur comprise entre 0,9 mm et 1,3 mm) afin d’éviter tout
problème mécanique lors du perçage du septum du flacon à échantillon à l’aide de l’aiguille métallique
de la seringue.
NOTE Cela est particulièrement important lors de l’utilisation de systèmes d’échantillonnage automatiques
qui font tourner les flacons, car l’aiguille métallique de la seringue (y compris la fibre exposée) peut être
endommagée lors de l’extraction.
L’extraction de certaines des substances énumérées dans le Tableau 1 selon le mode opératoire décrit à
l’Article 8 dépend de la température. En règle générale, des rendements d’extraction un peu plus élevés
sont obtenus à des températures plus faibles. Il est nécessaire de maintenir constante la température
d’extraction (par exemple 30 °C) au cours d’une séquence d’analyse pour tous les échantillons afin
d’obtenir des rendements d’extraction reproductibles.
4.3 Interférences lors du mode opératoire de chromatographie en phase gazeuse et
spectrométrie de masse
Les interférences peuvent être causées, par exemple par le système d’injection utilisé ou par une
séparation inadéquate des analytes. Des opérateurs expérimentés, utilisant les informations fournies
dans les notices des instruments, peuvent être capables de minimiser ce type d’interférence. Une
vérification régulière du système de chromatographie en phase gazeuse et spectrométrie de masse est
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ISO 27108:2010(F)
nécessaire pour maintenir un niveau de performance approprié. Il convient que le système requis soit
régulièrement vérifié à l’aide d’un étalon CG.
Vérifier la profondeur de pénétration requise des fibres pour la désorption thermique dans l’injecteur
du chromatographe en phase gazeuse. La profondeur de pénétration correspond au point le plus chaud
de l’injecteur et doit être maintenue constante durant une séquence de mesure.
5 Réactifs
Les réactifs doivent être exempts d’impuretés susceptibles d’interférer avec l’analyse CG-SM.
Utiliser des solvants et des réactifs d’une pureté suffisante, c’est-à-dire contenant des impuretés en
concentration négligeable par rapport à la concentration des analytes à déterminer. En ce qui concerne
les réactifs, utiliser, autant que possible, des réactifs de «grade résiduel» ou mieux afin d’obtenir de
faibles concentrations de blancs. Vérifier par des déterminations à blanc et, si nécessaire, exécuter des
opérations de nettoyage supplémentaires.
5.1 Eau, conforme aux exigences de l’ISO 3696, qualité 1 ou équivalente.
5.2 Gaz porteurs pour chromatographie en phase gazeuse-spectrométrie de masse, de grande
pureté et conformes aux spécifications du fabricant.
5.3 Chlorure de sodium, NaCl.
5.4 Solvants, par exemple acétate d’éthyle, C H O ; acétone (propanone), C H O; acétonitrile, CH CN.
4 8 2 3 6 3
Pour la préparation de solutions mères de substances de référence individuelles (5.9.2), utiliser le solvant
approprié. Toutefois, il est recommandé de préparer des solutions mères multi-composants (5.9.3) en
utilisant de l’acétone ou de l’acétate d’éthyle.
5.5 Solution d’hydroxyde de sodium, w(NaOH) = 25 % fraction massique.
5.6 Acide chlorhydrique, w(HCl) = 25 % fraction massique ou acide sulfurique, w(H SO ) = 12,5 %
2 4
fraction massique.
5.7 Thiosulfate de sodium pentahydraté, Na S O , 5 H O.
2 2 3 2
5.8 Étalon interne, par exemple atrazine-d , lindane-d ou parathion-éthyl-d .
5 6 10
En ce qui concerne l’étalon interne, choisir une substance ayant des propriétés physiques et chimiques
(par exemple comportement à l’extraction, temps de rétention) similaires à celles de la substance à
déterminer. Il convient que l’étalon interne ne soit pas présent dans l’échantillon à analyser. Le choix
d’une substance peut être difficile et il peut dépendre de la nature du problème à résoudre; dans tous
les cas, il convient de vérifier l’aptitude de la substance. Il est vivement recommandé d’utiliser, comme
13
étalon interne, une substance marquée au deutérium ou une substance enrichie en C parmi celles
énumérées dans le Tableau 1. Il peut être avantageux d’utiliser plus d’un étalon interne.
Préparer des solutions mères de substances étalons internes individuelles en procédant de la même
manière que celle spécifiée pour les substances de référence individuelles (5.9.2).
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ISO 27108:2010(F)
5.9 Substances de référence
5.9.1 Généralités
Substances de référence (énumérées dans le Tableau 1) de concentration définie, appropriées pour
la préparation de solutions mères et pour la préparation de solutions de référence multi-composants
aqueuses dopées utilisées pour l’étalonnage du mode opératoire total (9.2).
5.9.2 Solutions mères de substances de référence individuelles
Par exemple, introduire 50 mg d’une substance de référence dans une fiole jaugée à un trait de 100 ml
(6.6), dissoudre dans un solvant approprié (5.4) et compléter jusqu’au trait repère avec le même solvant.
Conserver les solutions mères à des températures comprises entre 1 °C et 5 °C conformément à
l’ISO 5667-3, à l’abri de la lumière. Les solutions sont stables pendant au moins 12 mois.
NOTE La congélation des solutions mères est également possible et cette pratique est courante.
5.9.3 Solutions mères multi-composants de substances de référence
Par exemple, transvaser 1 ml de chacune des solutions des substances individuelles (5.9.2) et des
substances étalons internes (5.8) dans une fiole jaugée de 100 ml (6.6) et compléter jusqu’au trait repère
avec de l’acétate d’éthyle ou de l’acétone (5.4).
Conserver les solutions mères multi-composants à des températures comprises entre 1 °C et 5 °C, à l’abri
de la lumière. Elles sont stables pendant au moins 6 mois.
5.9.4 Solutions de référence multi-composants aqueuses utilisées pour l’étalonnage du mode
opératoire total
Préparer la solution de référence aqueuse pour l’étalonnage du mode opératoire total de la manière suivante.
Mesurer 100 ml d’eau, par exemple dans une fiole jaugée à un trait (6.6) et ajouter un barreau magnétique.
Placer la fiole sur un agitateur magnétique et mettre celui-ci en marche.
À l’aide d’une microseringue, mesurer un volume de 10 µl de solution mère multi-composants (5.9.3) et
l’introduire sous la surface de l’eau agitée. Poursuivre l’agitation pendant 5 min environ avec la fiole fermée.
Régler la vitesse d’agitation de manière à éviter toute formation de tourbillon.
Préparer des solutions de référence de concentrations plus élevées et moins élevées de la même manière
en utilisant des solutions mères multi-composants (5.9.3) préparées en conséquence. Il convient que
toutes les solutions de référence aqueuses appropriées pour un étalonnage multipoint contiennent des
volumes égaux d’étalon interne.
Ne pas diluer les solutions aqueuses dopées.
Toujours garder le volume de dopage constant.
NOTE Un petit volume de dopage (par exemple 10 µl dans 100 ml d’eau) est recommandé pour éviter toute
interférence du solvant lors du processus d’adsorption par la fibre des analytes étudiés.
Conserver les solutions de référence à des températures comprises entre 1 °C et 5 °C, à l’abri de la lumière.
Il est possible qu’elles ne soient plus stables au bout de quelques jours; par conséquent, elles doivent être
préparées chaque jour de travail.
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ISO 27108:2010(F)
6 Appareillage
L’équipement ou les parties de celui-ci qui sont susceptibles de venir au contact de l’échantillon ou de
son extrait doivent être exempts de résidus générant des interférences. Il est recommandé d’utiliser des
récipients en verre, en acier inoxydable ou en polytétrafluoroéthylène (PTFE).
Équipement de laboratoire courant et, en particulier, les éléments suivants.
6.1 Fioles à échantillons, par exemple en verre fumé, à fond plat, munies de bouchons en verre ou
revêtues de PTFE, par exemple d’une capacité de 100 ml ou 250 ml.
6.2 Flacons à échantillons en verre (flacons à espace de tête), munis de bouchons (6.3), par exemple
d’une capacité de 10 ml ou 20 ml.
6.3 Bouchons sertis, munis de septa revêtus de PTFE (par exemple bouchons magnétiques munis de
septa en butyle/PTFE, d’épaisseur comprise entre 0,9 mm et 1,3 mm).
NOTE Les flacons à espace de tête disponibles dans le commerce sont habituellement munis d’une collerette
à bride adaptée pour un septum de 3 mm. Un septum plus mince (par exemple d’une épaisseur comprise entre
0,9 mm et 1,1 mm) nécessite l’utilisation de flacons adaptés munis d’une collerette à bride de plus grande épaisseur.
Sinon, une bague d’épaisseur perforée (par exemple en caoutchouc naturel ou en butyle, d’épaisseur 1,3 mm) peut
être placée entre le septum et le bouchon serti.
6.4 Outil de sertissage et pince à décapsuler (par exemple outil de sertissage manuel et pince à
décapsuler, 20 mm).
[3]
6.5 Éprouvettes graduées, par exemple, de capacité 100 ml ou 250 ml, ISO 4788
classe A.
[2]
6.6 Fioles jaugées à un trait, par exemple, de capacité 10 ml, 25 ml, 50 ml et 100 ml, ISO 1042 classe A.
[1]
6.7 Pipettes à un volume, de capacités comprises entre 1 ml et 50 ml, ISO 648 classe A.
6.8 Microseringues, par exemple de capacités comprises entre 5 µl et 50 µl.
6.9 Agitateur magnétique, y compris des barreaux magnétiques d’agitation revêtus de PTFE de
taille appropriée.
6.10 Appareil de chromatographie en phase gazeuse sur capillaire avec détecteur par
spectrométrie de masse (CG-SM) utilisant le mode d’ionisation par impact électronique, alimentation
en gaz conforme aux instructions des fabricants respectifs.
6.11 Injecteur CG sans discrimination, par exemple en mode «splitless» d’un système d’injection de
type «split/splitless» ou vaporisateur à température programmée (VTP).
6.12 Dispositif d’échantillonnage automatique avec option MEPS, comprenant une seringue MEPS
et le logiciel nécessaire.
6.13 Fibres MEPS, par exemple 10 mm, à phases «polyacrylate» moyennement polaires (revêtement
PA: 85 μm, par exemple) ou à phases «polydiméthylsiloxane/divinylbenzène» bipolaires (revêtement
PDMS/DVB: 65 μm, par exemple). D’autres fibres que celles mentionnées ci-dessus peuvent également
être utilisées. Toutefois, il est nécessaire de vérifier leur sensibilité pour les substances étudiées (voir 9.1).
NOTE Il s’est avéré que les phases «polyacrylate» (PA 85) étaient les plus sensibles pour les substances
énumérées dans le Tableau 1.
6 © ISO 2010 – Tous droits réservés
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ISO 27108:2010(F)
Utiliser de préférence des aiguilles de calibre 23 (notamment en combinaison avec un système d’entrée
de chromatographie en phase gazeuse sans septum). Si un système d’injection à septum est utilisé, il
convient d’utiliser des aiguilles de calibre 24 pour réduire l’évidement du septum.
6.14 Colonnes capillaires, pour chromatographie en phase gazeuse (des exemples de chromatographes
figurent en Annexe A). Il est avantageux d’utiliser des
...
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