ISO/TS 16780:2015

TECHNICAL ISO/TS
SPECIFICATION 16780
First edition
2015-08-15
Water quality — Determination of
polychlorinated naphthalenes (PCN)
— Method using gas chromatography
(GC) and mass spectrometry (MS)
Qualité de l’eau — Détermination des naphtalènes polychlorés
(PCN) — Méthode par chromatographie en phase gazeuse (CG) et
spectrométrie de masse (SM)
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, and abbreviated terms . 2
3.1 Terms and definitions . 2
3.2 Abbreviated terms . 6
4 Principle . 6
4.1 Extraction . 6
4.2 Clean-up . 7
4.3 Identification and quantification . 7
4.4 Quality . 8
5 Contamination and interferences . 8
6 Reagents and standards .10
7 Apparatus and materials.16
8 Sample collection, preservation, storage and holding times .19
8.1 General .19
8.2 Storage times .19
9 Quality assurance and quality control .20
9.1 General .20
9.2 Spiking .20
9.3 Recovery of labelled compounds assessment .21
9.4 Method blanks .21
9.5 QC check sample .21
10 Calibration .21
10.1 Operating conditions .21
10.2 Mass spectrometer resolution .22
10.3 Ion abundance ratios, minimum levels, signal-to-noise ratios, and absolute
retention times .22
10.4 Retention time .22
10.5 Column resolution performance check .23
10.6 Calibration by isotope dilution .23
10.7 Calibration by internal standard .23
10.8 Combined calibration .24
10.8.1 General.24
10.8.2 Data storage .24
10.8.3 Data acquisition .24
10.8.4 Response factors and multipoint calibrations . .24
11 Sample preparation .25
11.1 General .25
11.2 Determination of solid particulate material .25
11.3 Preparation of aqueous samples containing 2 g/l of solid particulate material or less .25
11.3.1 General.25
11.3.2 Preparation of sample and QC aliquots .26
11.3.3 Filtration of particles . .26
12 Extraction .26
12.1 Separating funnel extraction of filtrates and of aqueous samples that are visibly
absent of particles .26
12.2 Solid phase extraction (SPE) of samples containing less than 2 g/l suspended
particlulate matter .27
12.2.1 Disk/cartridge preparation .27
12.2.2 Sample extraction .27
12.3 Soxhlet or PLE extraction of filters or disks .28
12.4 Macro-concentration .28
12.4.1 General.28
12.4.2 Rotary evaporation .28
12.4.3 Heating mantle .29
12.4.4 Kuderna-Danish (K-D) .29
12.5 Micro-concentration and solvent exchange .31
13 Extract clean-up.31
13.1 General .31
13.2 Back-extraction with acid and base .32
13.3 Gel permeation chromatography (GPC) .32
13.3.1 Column packing .32
13.3.2 Column calibration .32
13.3.3 Extract clean-up .33
13.4 Silica clean-up .33
13.5 Carbon column .34
13.6 Florisil clean-up .34
13.7 Silver nitrate–silica column .34
14 HRGC–HRMS analysis .35
14.1 General .35
14.2 MS resolution .35
14.3 Calibration verification .35
14.4 GC resolution .35
14.5 Blank .35
15 Qualitative determination .36
16 Quantitative determination .36
16.1 Isotope dilution quantification .36
16.2 Internal standard quantification .37
16.3 Determination of labelled compound recovery .37
16.4 Concentration in sample .38
16.4.1 General.38
16.4.2 Treatment of samples exceeding calibration range .38
16.5 Results and reporting .38
17 Test report .39
Annex A (informative) Use of alternate mass spectrometry detectors (LRMS, MS–MS) .40
Annex B (informative) Quality control and initial precision and recovery .43
Annex C (informative) Calculation of toxic equivalents .45
Annex D (informative) Pollution prevention .46
Annex E (informative) Waste management .47
Bibliography .48
iv © ISO 2015 – All rights reserved

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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 147, Water quality, Subcommittee SC 2, Physical,
chemical and biochemical methods.
TECHNICAL SPECIFICATION ISO/TS 16780:2015(E)
Water quality — Determination of polychlorinated
naphthalenes (PCN) — Method using gas chromatography
(GC) and mass spectrometry (MS)
WARNING — Persons using this Technical Specification should be familiar with normal
laboratory practice. This Technical Specification 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.
Attention is drawn to any relevant national safety regulations. A number of PCN congeners have
dioxin-like properties and are toxic chemicals. All work with PCNs requires the utmost care;
the national safety measures which correspond to those for toxic substances shall be strictly
followed.
IMPORTANT — It is absolutely essential that tests conducted in accordance with this Technical
Specification be carried out by suitably trained staff.
1 Scope
This Technical Specification specifies a method for the determination of polychlorinated naphthalenes
(PCNs), where “poly” means “mono” to “octa”, in waters and waste waters [containing less than 2 g/l
solid particulate material (SPM)] using high resolution gas chromatography–high resolution mass
spectrometry (HRGC–HRMS).
NOTE 1 The congeners analysed by this method are listed in Table 1.
The working range of the method is 20 pg/l to 8 ng/l. The method is optimized for PCNs, but can
be modified to include other coplanar compounds such as polychlorinated dioxins and furans
(PCDDs/PCDFs) and dioxin-like tetra- to heptachlorinated biphenyls (dlPCBs). This method can be used
to determine PCNs in other matrices (e.g. biota, sediments, air); however, additional clean-up steps and
techniques can be necessary for samples with high organic loadings. Low resolution mass spectrometry
(LRMS) and mass spectrometry–mass spectrometry (MS–MS) can be used.
NOTE 2 LRMS and MS–MS conditions are summarized in Annex A.
Both LRMS and MS–MS can be less selective than HRMS and there is a possibility of bias due to
interfering compounds if these techniques are used.
The detection limits and quantification levels in this method are dependent on the level of interferences
as well as instrumental limitations.
NOTE 3 The minimum levels (ML) in Table 4 are the levels at which the PCNs can typically be determined with
no interferences present.
This method is performance based. The analyst is permitted to modify the method, e.g. to overcome
interferences, provided that all performance criteria in this method are met.
NOTE 4 The requirements for establishing method validation or equivalency are given in Clause 9.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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: Preservation and handling of water samples
ISO 8466 (all parts), Water Quality — Calibration and evaluation of analytical methods and estimation of
performance characteristics
3 Terms, definitions, and abbreviated terms
For the purposes of this document, the following terms, definitions, and abbreviated terms apply.
3.1 Terms and definitions
3.1.1
analyte
substance to be determined
EXAMPLE A polychlorinated naphthalene (PCN) congener tested for by the method specified in
this Technical Specification.
Table 1 — PCNs determined by this method
PCN No. (Reference[4]) Chlorine substitution CAS Registry No.
Total MonoCNs Mono congener total
2 2-MonoCN 91–58–7
Total DiCNs Di congener total
6 1,5-DiCN 1825–30–5
Total TriCNs Tri congener total
13 1,2,3-TriCN 50402–52–3
Total TetraCNs Tetra congener total
27 1,2,3,4-TetraCN 20020–02–4
28 1,2,3,5-TetraCN 53555–63–8
36 1,2,5,6-TetraCN 67922–22–9
42 1,3,5,7-TetraCN 53555–64–9
46 1,4,5,8-TetraCN 3432–57–3
48 2,3,6,7-TetraCN 34588–40–4
Total PentaCNs Penta congener total
49 1,2,3,4,5-PentaCN 67922–25–2
50 1,2,3,4,6-PentaCN 67922–26–3
52/60 1,2,3,5,7-/ 53555–65–0/
1,2,4,6,7-PentaCN 150224–17–2
53 1,2,3,5,8-PentaCN 150224–24–1
54 1,2,3,6,7-PentaCN 150224–16–1
Total HexaCNs Hexa congener total
63 1,2,3,4,5,6-HexaCN 58877–88–6
64/68 1,2,3,4,5,7-/ 67922–27–4/
1,2,3,5,6,8-HexaCN 103426–95–5
2 © ISO 2015 – All rights reserved

Table 1 (continued)
PCN No. (Reference[4]) Chlorine substitution CAS Registry No.
66/67 1,2,3,4,6,7-/ 103426–96–6
1,2,3,5,6,7-HexaCN 103426–97–7
69 1,2,3,5,7,8-HexaCN 103426–94–4
70 1,2,3,6,7,8-HexaCN 17062–87–2
71/72 1,2,4,5,6,8-/ 90948–28–0
1,2,4,5,7,8-HexaCN 103426–92–2
Total HeptaCNs Hepta congener total
73 1,2,3,4,5,6,7-HeptaCN 58863–14–2
74 1,2,3,4,5,6,8-HeptaCN 58863–15–3
75 (OctaCN) 1,2,3,4,5,6,7,8-OctaCN 2234–13–1
[4]
Note: PCN numbering nomenclature is detailed in Reference . The CAS Registry Number is a unique numeri-
cal identifier assigned by Chemical Abstracts Service (CAS) to every chemical substance described in the open
scientific literature.
3.1.2
calibration standard
solution prepared from a secondary standard or stock solutions and used to calibrate the response of
the instrument with respect to analyte concentration
[SOURCE: ISO 17858:2007, 3.1.2 — modified]
3.1.3
calibration verification standard
VER
midpoint calibration standard that is used to verify calibration
[SOURCE: ISO 17858:2007, 3.1.3]
3.1.4
congener
member of the same kind, class or group
[SOURCE: ISO 17858:2007, 3.1.5]
EXAMPLE Any one of the 75 individual PCNs.
3.1.5
critical pair
pair of isomers that must be separated to a predefined degree (e.g. 50 % valley) to ensure
chromatographic separation meets minimum quality criteria
[SOURCE: ISO 17858:2007, 3.1.6, modified — “50 %” replaces “25 %”.]
3.1.6
dioxin-like isomer
PCN for which a relative potency to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been calculated see
Table 2
[16]
Table 2 — Examples of relative potencies
Compound REP
1,3,5,7CN(42) 0,000 01
1,2,5,6CN(36) 0,000 01
Table 2 (continued)
Compound REP
1,2,3,5CN(28) 0,000 001
1,2,3,4CN(27) 0,000 01
2,3,6,7CN(48) 0,001
1,4,5,8CN(46) 0,000 000 1
1,2,3,5,7CN/1,2,4,6,7CN(52/60) 0,000 1
1,2,3,4,6CN(50) 0,000 1
1,2,3,6,7CN(54) 0,000 1
1,2,3,5,8CN(53) 0,000 01
1,2,3,4,5CN(49) 0,000 001
1,2,3,4,6,7CN/1,2,3,5,6,7CN(66/67) 0,01
1,2,3,4,5,7CN/1,2,3,5,6,8CN(64/68) 0,001
1,2,3,5,7,8CN(69) 0,001
1,2,4,5,6,8CN/1,2,4,5,7,8CN(71/72) 0,001
1,2,3,4,5,6CN(63) 0,001
1,2,3,6,7,8CN(70) 0,01
1,2,3,4,5,6,7CN(73) 0,01
1,2,3,4,5,6,8CN(74) 0,01
1,2,3,4,5,6,7,8CN(75) 0,1
3.1.7
homologue group
complete group of isomers
EXAMPLE Tetrachloronaphthalenes.
[SOURCE: ISO 17858:2007, 3.1.8 — modified]
3.1.8
isotope dilution
method using labelled (usually C) internal standards to correct for losses during sample preparation
and analysis
13 13
[SOURCE: ISO 17858:2007, 3.1.9, modified — “ C” replaces “ C ”.]
3.1.9
method blank
aliquot of reagent water free of analytes treated exactly as a sample through the complete analytical
procedure including extraction, clean-up, identification and quantification including all relevant
reagents and materials
[SOURCE: ISO 17858:2007, 3.1.11, modified — “free of analytes” replaces “that is”.]
3.1.10
recovery standard
C -labelled PCN added before injection into the GC, to monitor variability of instrument response,
and determine recovery of surrogate/internal standards
Note 1 to entry: An alternate compound with similar properties can be used if a labelled PCN standard
is not available.
4 © ISO 2015 – All rights reserved

3.1.11
solid particulate material
SPM
suspended solids
non dissolved particle matter present in the sample
3.1.12
toxic equivalent factor
TEF
relative toxicity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)
[SOURCE: ISO 17858:2007, definition 3.1.17]
3.1.13
toxic equivalent quantity
TEQ
sum of toxic equivalents of each individual congener
[SOURCE: ISO 17858:2007, 3.1.18]
3.1.14
surrogate standard
C -labelled PCN added to the sample prior to analysis and used to correct for losses of the PCN
analytes during sample extraction or clean-up
Note 1 to entry: Surrogate standards have the same chemical formula and structure as the analyte of interest.
3.1.15
internal standard
C -labelled PCN or analogue added to the sample prior to analysis and used to correct for losses of
the PCN analytes during sample extraction or clean-up
Note 1 to entry: Internal standards do not have the same structure as the analyte of interest but can or may not
have the same chemical formula.
3.2 Abbreviated terms
AR analytical reagent
CRM certified reference material
GC–MS gas chromatography–mass spectrometry
GPC gel permeation chromatography
HPLC high performance liquid chromatography
HRGC high resolution gas chromatography
HRMS high resolution mass spectrometry
IPR initial precision and recovery
LRMS low-resolution mass spectrometry
MDL method detection limit
ML minimum level
PAR precision and recovery
PCB polychlorinated biphenyl
PCDD/PCDF polychlorinated dibenzo-p-dioxin/dibenzofuran
PCN polychlorinated naphthalene
PFK perfluorokerosene
PLE pressurized liquid extractor
SIM selected ion monitoring
SMS spiked matrix samples
SPE solid-phase extraction
SPM solid particulate material
TEF toxic equivalent factor
TEQ toxic equivalent quantity
VER calibration verification standard
4 Principle
4.1 Extraction
4.1.1 Stable isotopically labelled analogues of PCNs (diluted in a suitable solvent such as 2-propanone)
are spiked into a ~1 l aqueous sample. Sample size can be adjusted in order to meet required detection
limits and data quality objectives. Where available, a minimum of one labelled standard per homologue
group should be used and the sample extracted using the procedures as specified in 4.1.2 or 4.1.3.
6 © ISO 2015 – All rights reserved

4.1.2 Samples containing no visible particles are extracted using liquid/liquid extraction or by solid
phase extraction (SPE) cartridge or disk. The extract is concentrated for clean-up.
4.1.3 Samples containing visible particles are vacuum filtered through a glass fibre filter. The filter
is extracted in a Soxhlet extractor or a pressurized liquid extractor (PLE). The filtrate is extracted in a
separating funnel. The extract is concentrated and combined with the Soxhlet extract prior to clean-up.
Alternatively, the sample is vacuum filtered through a solid phase extraction (SPE) disk or cartridge.
The disk is eluted with suitable solvent mixtures or extracted in a Soxhlet or a PLE, and the extract is
concentrated for clean-up.
NOTE Other solvents and extraction techniques can be substituted, provided that all the performance
criteria are met.
4.2 Clean-up
After extraction, sample extracts are cleaned to remove interfering components. Sample clean-up
1)
procedures may include washes with acid or base, gel permeation, silica, Florisil and activated carbon
chromatography. Due to the large number of potential interfering compounds, efforts should be taken
to ensure unique identification and accurate quantification of as many PCN congeners as possible.
4.3 Identification and quantification
An individual PCN is identified by comparing the GC retention time and ion abundance ratio of two
exact masses monitored (see Table 3) with the corresponding retention time of a labelled internal
standard (isotope dilution) and the theoretical or acquired ion abundance ratio of the two exact masses.
The isomers and congeners for which there are no labelled analogues (internal standard method) are
identified when retention times or relative retention times and ion abundance ratios agree within
predefined limits.
NOTE Resolution of greater than or equal to 10 000 is recommended. High resolution gas chromatography–
high resolution mass spectrometry (HRGC–HRMS) at a resolution of greater than or equal to 10 000 is at present
required to achieve adequate sensitivity and selectivity, and to allow the use of some C labelled standards.
Resolutions of less than 10 000 can be used for specific analytes groups (PCBs, PCNs) where the matrix and
potential interferences such as chlordane and related compounds are well characterized.
Table 3 — Congener function groups and ions
Quantitation ions Dwell Delay Theoretical
Function
Compound isotopic Acceptable range
group
m/z ms ms
ratio
a
162,0236 , 164,0208 MonoCNs 50 10 0,33 0,17 to 0,48
a
0 195,9847 , 197,9818 DiCNs 50 10 0,65 0,50 to 0,80
180,9888 PFK Lock Mass 30 10
a
229,9457 , 231,9428 TriCNs 50 10 1,02 0,87 to 1,17
a
1 265,9038 , 263,9067 TetraCNs 50 10 1,30 1,11 to 1,5
a 13
275,9373 , 273,9402 C -TetraCNs 25 10 1,30 1,11 to 1,5
268,9824 PFK Lock Mass 30 10
a
Most abundant ion.
b
Injection standard.
13 13
NOTE When the availability of C-labeled PCN standards is limited, C-labeled PCB standards can be used as injection
standards
1) Florisil is the trade name of a product supplied by US Silica Co. This information is given for the convenience of
users of this document and does not constitute an endorsement by ISO of the product named. Equivalent products
may be used if they can be shown to lead to the same results.
Table 3 (continued)
Quantitation ions Dwell Delay Theoretical
Function
Compound isotopic Acceptable range
group
m/z ms ms
ratio
a
299,8648 , 297,8677 PentaCNs 50 10 1,62 1,38 to 1,86
a 13
2 309,8983 , 307,9013 C -PentaCNs 25 10 1,62 1,38 to 1,86
b
292,9824 PFK Lock Mass 30 10
a
333,8258 , 335,8229 HexaCNs 50 10 1,23 1,01 to 1,45
a 13
343,8594 345,8564 C -HexaCNs 25 10 1,23 1,01 to 1,45
a 13 b
337,9207 ,335,9236 C -PentaCB 25 10 1,62 1,38 to 1,86
342,9792 PFK Lock Mass 30 10
a
367,7868 , 369,7839 HeptaCNs 50 10 1,02 0,87 to 1,17
a 13
4 377,8204 , 379,8174 C HeptaCNs 50 10 1,15 0,98 to 1,32
380,9760 PFK Lock Mass 30 10
a
403,7449 , 401,7479 OctaCN 50 10 1,15 0,98 to 1,32
a 13
413,7785 , 411,7814 C -OctaCN 25 10 1,15 0,98 to 1,32
a 13 b
405,8428 ,407,8398 C -HeptaCB 25 10 1,02 0,87 to 1,17
392,9760 PFK Lock Mass 30 10
a
Most abundant ion.
b
Injection standard.
13 13
NOTE When the availability of C-labeled PCN standards is limited, C-labeled PCB standards can be used as injection
standards
4.4 Quality
The quality of the analysis is ensured through reproducible calibration and testing of the extraction,
clean-up, and GC–MS systems. Interferences, biases and limitations should be determined and identified
for each target analyte through intercalibration (round-robin) studies, certified reference materials
(CRMs) and spiked matrix samples (SMSs). A series of quality control (QC) samples (CRM, SMS) should
be analysed with each set of samples and monitored through control charting or other quality review
procedures.
5 Contamination and interferences
5.1 Reagents. Solvents, reagents, laboratory-ware, and other sample processing hardware can yield
artefacts or elevated baselines causing misinterpretation of chromatograms. Check reagents for potential
interfering compounds and clean and check laboratory-ware to ensure that analytes of interest are not
present. Specific selection of reagents and purification may be required. When a clean reference matrix
that simulates the sample matrix under test is not available, use reagent water (6.6) or a matrix that most
closely resembles the sample.
5.2 Clean laboratory-ware, to meet the method blank requirements of this method (9.4).
An example of a cleaning procedure follows.
Dismantle laboratory-ware with removable parts, particularly separating funnels with fluoropolymer
stopcocks, prior to detergent washing. Rinse laboratory-ware with solvent and wash with a detergent
solution as soon after use as is practical. Sonication of laboratory-ware containing a detergent solution
for approximately 30 s may aid in cleaning.
8 © ISO 2015 – All rights reserved

After detergent washing, rinse laboratory-ware immediately with hot tap water. The tap water rinse
shall be followed by solvent rinse or soak, using a suitable solvent (6.3) to remove contaminants. For
known contaminated laboratory-ware, use toluene as a final rinse or soak.
Number each piece of re-usable laboratory-ware or minimally identify each set of specific type of
laboratory-ware (e.g. Soxhlet extractors, round-bottomed flasks) to associate that specific laboratory-
ware with the processing of a particular sample or set of samples. This practice assists the laboratory
in tracking possible sources of contamination for individual samples, identifying laboratory-ware
associated with highly contaminated samples that may require extra cleaning, and determining when
laboratory-ware shall be discarded.
IMPORTANT — Proper cleaning of laboratory-ware is extremely important, because laboratory-
ware can contaminate the samples, but can also remove the analytes of interest by surface
adsorption if the surface is activated during the cleaning procedure. Glassware can be checked
for contamination by analysing solvent rinses.
Demonstrate that all materials used in the analysis are free from interferences by running reference
matrix method blanks initially and with each sample batch (to a maximum of 20 samples); (see 9.4,
14.5).
The reference matrix shall simulate, as closely as possible, the sample matrix under test. Ideally, the
reference matrix shall not contain analytes in detectable amounts, but shall contain matrix compounds
and potential interferents in the concentrations expected to be found in the samples to be analysed.
NOTE Interferences co-extracted from samples can vary considerably from source to source, depending
on the diversity of the site being sampled. Interfering compounds, including PCBs of higher degrees of Cl
substitution, dibenzofurans of lower degrees of Cl substitution, chlordane and related compounds and
labelled dibenzo-p-dioxins can be present at concentrations orders of magnitude higher than the PCNs being
analysed. Because the levels of PCNs are measured by this method are typically lower than these compounds,
the elimination of interferences is essential. The example clean-ups given in Clause 13 can be used to reduce
or eliminate these interferences and thereby permit reliable determination of the PCNs at the levels shown in
Table 4.
Table 4 — Suggested quantification relationships
a a
PCN Quantification reference Minimum level Minimum level
Waters (pg/l) Extract (pg/µl)
Total MonoCNs C -PCN 42 20 1,0
2-MonoCN (2) C -PCN 42 20 1,0
Total DiCNs C -PCN 42 20 1,0
1,5-DiCN (6) C -PCN 42 20 1,0
Total TriCNs C -PCN 42 20 1,0
1,2,3-TriCN (13) C -PCN 42 20 1,0
Total TetraCNs Mean of C -PCN 27/42 20 1,0
1,2,3,4-TetraCN (27) C -PCN 27 20 1,0
1,2,3,5-TetraCN (28) Mean of C -PCN 27/42 20 1,0
1,2,5,6-TetraCN (36) Mean of C -PCN 27/42 20 1,0
1,3,5,7-TetraCN (42) C -PCN 42 20 1,0
1,4,5,8-TetraCN (46) Mean of C -PCN 27/42 20 1,0
2,3,6,7-TetraCN (48) Mean of C -PCN 27/42 20 1,0
a
The minimum level ML for each analyte is defined as the level for which the entire analytical system shall give a
recognizable signal and acceptable calibration point. It is equivalent to the concentration of the lowest calibration standard,
assuming that all method-specific sample masses/volumes and clean-up procedures have been used. i.e. based on 1 l of
sample.
NOTE Minimum levels are given for guidance only. Mean refers to mean recovery of both internal standards.
Table 4 (continued)
a a
PCN Quantification reference Minimum level Minimum level
Waters (pg/l) Extract (pg/µl)
Total PentaCNs C -PCN 52 20 1,0
1,2,3,4,5-PentaCN (49) C -PCN 52 20 1,0
1,2,3,4,6-PentaCN (50) C -PCN 52 20 1,0
1,2,3,5,7-PentaCN (52)/
C -PCN 52 20 1,0
1,2,4,6,7-PentaCN (60)
1,2,3,5,8-PentaCN (53) C -PCN 52 20 1,0
1,2,3,6,7-PentaCN (54) C -PCN 52 20 1,0
Total HexaCNs C -PCN 64 20 1,0
1,2,3,4,5,6-HexaCN (63) C -PCN 64 20 1,0
1,2,3,4,5,7-HexaCN (64)/
C -PCN 64 20 1,0
1,2,3,5,6,8-HexaCN (68)
1,2,3,4,6,7-HexaCN (66)/
C -PCN 64 20 1,0
1,2,3,5,6,7-HexaCN (67)
1,2,3,5,7,8-HexaCN (69) C -PCN 64 20 1,0
1,2,3,6,7,8-HexaCN (70) C -PCN 64 20 1,0
1,2,4,5,6,8-HexaCN (71)/
C -PCN 64 20 1,0
1,2,4,5,7,8-HexaCN (72)
Total HeptaCNs C -PCN 75 20 1,0
1,2,3,4,5,6,7-HeptaCN (73) C -PCN 75 20 1,0
1,2,3,4,5,6,8-HeptaCN (74) C -PCN 75 20 1,0
1,2,3,4,5,6,7,8-OctaCN (75) C -PCN 75 20 1,0
a
The minimum level ML for each analyte is defined as the level for which the entire analytical system shall give a
recognizable signal and acceptable calibration point. It is equivalent to the concentration of the lowest calibration standard,
assuming that all method-specific sample masses/volumes and clean-up procedures have been used. i.e. based on 1 l of
sample.
NOTE Minimum levels are given for guidance only. Mean refers to mean recovery of both internal standards.
6 Reagents and standards
If not stated otherwise, use reagent grade chemicals.
6.1 pH adjustment and back-extraction
6.1.1 Water, H O according to grade 3 in ISO 3696.
6.1.2 Potassium hydroxide solution, dissolve 20 g of potassium hydroxide (KOH) in 100 ml of water.
6.1.3 Sulfuric acid, ρ(H SO ) = 1,84 mg/l.
2 4
6.1.4 Hydrochloric acid, c(HCl) = 6 mol/l.
6.1.5 Sodium chloride solution, dissolve 5 g of sodium chloride (NaCl) in 100 ml of water.
6.1.6 Sodium thiosulfate, Na S O .
2 2 3
10 © ISO 2015 – All rights reserved

6.2 Reagents for drying and evaporation
6.2.1 Sodium sulfate, Na SO , granular, anhydrous, baked at 300 °C for 24 h minimum, cooled in a
2 4
desiccator, and stored in a pre-cleaned glass bottle with screw cap that prevents moisture from entering.
If, after heating, the sodium sulfate develops a noticeable greyish cast (due to the presence of carbon
in the crystal matrix), discard that batch of reagent as it is not suitable for use. Rinse with about 20 ml
of dichloromethane (6.3.6) per gram of Na SO or extract with dichloromethane (6.3.6) if background
2 4
contamination is detected.
6.2.2 Prepurified nitrogen, N , volume fraction 99,999 %.
6.3 Solvents for extraction and clean-up, in glass, pesticide quality, free of interferences.
6.3.1 2-Propanone (Acetone), C H O.
3 6
6.3.2 Toluene, C H .
7 8
6.3.3 Cyclohexane, C H .
6 12
6.3.4 Hexane, C H .
6 14
6.3.5 Methanol, CH OH.
6.3.6 Dichloromethane, CH Cl .
2 2
6.3.7 Diethyl ether, C H O.
4 10
6.3.8 Ethanol, C H O.
2 6
6.3.9 Nonane, C H , distilled.
9 20
6.4 Gel permeation chromatography (GPC) calibration
6.4.1 GPC calibration solution, containing 300 mg/ml of corn oil, 15 mg/ml of bis(2-ethylhexyl)
phthalate (C H O ), 1,4 mg/ml of pentachlorophenol (C Cl OH), 0,1 mg/ml of perylene, (C H ), and
24 38 4 6 5 20 12
0,5 mg/ml of sulfur (S).
6.5 Adsorbents for sample clean-up
6.5.1 Silica, 70 µm to 230 µm.
Prepare each type of silica at least every 2 weeks.
6.5.1.1 Activated silica
Silica (6.5.1)baked at 180 °C for a minimum of 1 h, cooled in a desiccator, and stored in a pre-cleaned
glass bottle with screw cap that prevents moisture from entering.
6.5.1.2 Acid silica
To prepare 30 % mass
...