ISO/TS 21231:2019

TECHNICAL ISO/TS
SPECIFICATION 21231
First edition
2019-02
Water quality — Characterization of
analytical methods — Guidelines for
the selection of a representative matrix
Reference number
©
ISO 2019
© ISO 2019
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Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 4
5 Influence parameters . 5
5.1 Common parameters for all matrices . 5
5.2 Water intended for consumption . 6
5.3 Natural waters . 6
5.4 Waste waters . 6
5.5 Marine waters . 6
5.6 Recreational waters . 7
6 Selection of characteristic parameters of a matrix . 7
6.1 General . 7
6.2 All waters . 7
6.3 Waters intended for consumption . 7
6.4 Natural waters . 7
6.5 Waste waters . 7
6.6 Marine waters . 8
6.7 Recreational waters . 8
7 Available materials . 8
7.1 General . 8
7.2 Material obtained by reasonable dilution of a real matrix . 8
7.3 Artificial material . 9
7.4 Analyte-specific blank values in matrices. 9
8 Report . 9
Annex A (informative) Characterization of waters intended for human consumption and
mineral waters .10
Annex B (informative) Examples of preparation of artificial matrices and representative
characteristics .11
Annex C (informative) Occurrence of chemical substances in waste water, by industrial
activity sector .23
Annex D (informative) Leachate .32
Bibliography .33
Foreword
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This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2,
Physical, chemical and biochemical methods.
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iv © ISO 2019 – All rights reserved

Introduction
This document has been prepared for the validation of analytical methods applied to the water quality
field. It enables a laboratory to determine the characteristics of a material suitable for determination of
the performances of an analytical method itself.
It is not intended to provide an exhaustive inventory of all published recipes, but to propose a selection
of recipes supporting the characterization of the performances of analytical methods used by a
laboratory. For this reason, a restricted number of recipes are proposed. References giving access to
other recipes are available in the Bibliography.
This document includes four recipes for preparing marine waters and five recipes for waste waters
with controlled characteristics.
TECHNICAL SPECIFICATION ISO/TS 21231:2019(E)
Water quality — Characterization of analytical methods —
Guidelines for the selection of a representative matrix
1 Scope
This document specifies representative materials suitable for the determination of the performance
characteristics, including uncertainty, during the initial assessment of a quantitative method, used in a
laboratory, for physico-chemical water analysis.
This document focuses on five main types of water:
— waters intended for consumption (5.2);
— natural waters (5.3);
— waste waters (5.4);
— marine waters (5.5);
— recreational waters (5.6).
NOTE Other more specific or less common types of water can be incorporated in any of the above types
provided appropriate justifications. The characteristics of the standard matrix are compatible with the
characteristics of the samples handled.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 6107 (all parts), Water quality — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6107 (all parts) and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1 General vocabulary
3.1.1
matrix
set of constituents of the test sample, except the analyte (3.2.1)
Note 1 to entry: By extension, a matrix defines a group of waters characterized by similar analytical behaviour in
relation to the analytical method used.
3.1.2
accepted reference value
value that serves as an agreed-upon reference for comparison, and which is derived as:
a) a theoretical or established value, based on scientific principles;
b) an assigned or certified value, based on experimental work of some national or international
organization;
c) a consensus or certified value, based on collaborative experimental work under the auspices of a
scientific or engineering group;
d) when a), b) and c) are not available, the expectation of the (measurable) quantity, i.e. the mean of a
specified population of measurements
Note 1 to entry: In the specific context of this document, the accepted reference value (or conventionally true
value) of the sample is provided according to possibilities by:
— the value from a certified reference material certificate,
— the consensus value obtained from an inter-laboratory comparison,
— the arithmetic mean of the repeated measurement values according to the reference method,
— the target value by adding analyte to a representative matrix of the scope in question.
[SOURCE: ISO 5725-1:1994, 3.5]
3.1.3
reference material
material, sufficiently homogeneous and stable with respect to one or more specified properties, which
has been established to be fit for its intended use in a measurement process
[SOURCE: ISO Guide 35:2017, 3.1]
3.1.4
certified reference material
reference material (3.1.3), accompanied by a certificate, one or more of whose property values are
certified by a procedure which establishes traceability to an accurate realization of the unit in which
the property values are expressed, and for which each certified value is accompanied by an uncertainty
at a stated level of confidence
[SOURCE: ISO/TS 13530:2009, 3.2.7]
3.1.5
assessment procedure
procedure related to the establishment of the specifications for the performance of a new method and/
or experimental verification that a method meets theoretically derived quality criteria
3.2 Terms related to analytical methods
3.2.1
analyte
subject of the analytical method
3.2.2
analytical method
unambiguously written procedure describing all details required to carry out the analysis of the analyte
(3.2.1), namely: scope and field of application, principle and/or reactions, definitions, reagents, apparatus,
analytical procedures, calculations and presentation of results, performance data and test report
[SOURCE: ISO/TS 16489:2006, 3.3]
2 © ISO 2019 – All rights reserved

3.2.3
quantitative analytical method
analytical method for measuring the quantity of analyte (3.2.1)contained in the test sample
Note 1 to entry: The result can consist of a quantity in a given quantity of test sample.
3.2.4
limit of detection
output signal or value above which it can be affirmed, with a stated level of confidence, for example
95 %, that a sample is different from a blank sample containing no determinand of interest, and which
could be estimated by different means and shall be verified in the intended matrix
[SOURCE: ISO 6107-2:2006, 60, modified — “and which could be estimated by different means and shall
be verified in the intended matrix” has been added.]
3.2.5
limit of quantification
LOQ
lowest value of a determinand that can be determined with an acceptable level of accuracy, which could
be estimated by different means and shall be verified in the intended matrix
Note 1 to entry: For each matrix, this limit is related to the pair [analyte (3.2.1), method].
3.2.6
reasonable dilution
dilution conditions for reducing the concentration of a substance in a matrix without substantially
modifying the intrinsic characteristics of the matrix
3.2.7
matrix blank values
values of a given parameter obtained using a test conducted on a matrix giving rise to a result below the
limit of detection (3.2.4) for the analyte (3.2.1) in question
3.2.8
scope of the analytical method
combination of the various types of matrix and the analyte (3.2.1) concentration range covered, to
which the analytical method applies
Note 1 to entry: In addition to an indication of all the satisfactory performance conditions for each factor, the
scope of the analytical method may also include warnings in respect of known interferences from other analytes,
or inapplicability to some matrices or conditions.
3.3 Terms related to matrix
3.3.1
influence parameter
intrinsic characteristic of the matrix, independent of the analyte (3.2.1) concentration, a variation of
which is liable to modify the analytical result
3.3.2
representative matrix
sample for which all the intrinsic characteristics are characteristic of a type of water or the source of a
group of samples
3.3.3
salinity
mass in grams of solid substances contained in one kilogram of sea water, when the bromide and iodide
ions are replaced by their chloride equivalent, carbonates converted into oxides and all the organic
matter oxidized
3.3.4
leachate
water which has percolated through tipped refuse or other specified permeable material
Note 1 to entry: See Annex D.
[SOURCE: ISO 6107-7:2006, 23]
4 Principle
The purpose of this document is to specify the concept of a representative matrix and its characteristics
with a view to studying the performance of an analytical method.
For each analyte under test, the scope of an analytical method includes all the matrices under test,
their descriptive parameters, and the concentration ranges of the influence parameters for which the
method is applicable. The laboratory should define its requirements beforehand in respect of the scope
of the analytical method, selecting the materials most in line with requirements.
WARNING — The definition of the scope is entirely dependent on the analyst (the validation or
characterization study manager) and their knowledge acquired while developing the method.
It is sometimes preferable to segment a scope rather than seek to validate an overly general
method. In this case, a validation file should be compiled for each scope.
See Figure 1.
4 © ISO 2019 – All rights reserved

Figure 1 — Summary flow chart
5 Influence parameters
5.1 Common parameters for all matrices
The following influence parameters are liable to have an impact on analysis procedures. They shall help
classify the types of water on which the laboratory has validated its method or determined performance
characteristics.
— pH;
— ion composition and/or conductivity;
— salinity;
— dissolved organic carbon (DOC) and/or total organic carbon (TOC);
— colour or turbidity;
— suspended particular matter (SPM) content.
During the validation or characterization study, it is up to the laboratory to:
— define, for its practice, the characteristic ranges associated with each of the above parameters;
— justify, if applicable, the lack of influence thereof on the characterized method;
— complement this list with other characteristic parameters based on the methods and the source of
the samples analysed, using for example Annex A or Annex C.
5.2 Water intended for consumption
Water intended for human and livestock consumption is water considered to be fit for drinking.
Drinking water belongs to this category. It includes groundwater that has been chlorinated in the
resource.
The minimum additional characteristics to be included for this category are:
— disinfectant presence and content (distributed waters or groundwater chlorinated in the resource);
— CO content (natural mineral water), if relevant to subsequent specified analysis requirements.
5.3 Natural waters
Natural waters are waters taken from the natural environment not undergoing to any treatment other
than the addition of reagents for analyte preservation.
Surface waters and groundwater belong to this category. Brackish waters with salinity lower than
30 g/l are incorporated in this category.
Rainwater, which is generally not intended for consumption, are incorporated in this category.
5.4 Waste waters
Waste waters can originate from any combination of household, industrial or commercial activities.
They include collected run-offs and those from any spillage or infiltration from the waste water
collection system, including the contents of storm water tanks or ponds, discharged into collection
systems or into the environment.
NOTE 1 Waste waters can be collected in common systems or in separate systems.
NOTE 2 For the purposes of this document, the definition of waste water also includes untreated sanitary
waters.
NOTE 3 National or local regulations can include lists of substances of concern in relation to sewer discharges.
Annex C gives a list of examples of additional characteristics associated with some sectors of activity.
Some waste waters may have a high salinity.
5.5 Marine waters
Sea water consists of a large number of compounds distributed over the following categories: gases,
particulate matter, colloids, and dissolved elements (see Reference [7]).
6 © ISO 2019 – All rights reserved

The dissolved elements consist of 92 natural chemical elements, approximately two-thirds of which
are present in ultra-trace amounts and are difficult to detect. Sea water is characterized in that the
[8]
relative proportions of its 11 main constituents are substantially constant (Dittmar's law ) within
1 %. Dittmar's law can thus be used to determine the salinity of sea water by measuring only one of its
components.
The average salinity of sea water is 35 g/kg. It is generally between 30 g/kg (North Atlantic) and 40 g/
kg (Red Sea) but exhibits extreme values in closed or semi-closed seas (6 g/kg in the Baltic Sea, 330 g/
kg in the Dead Sea). The pH of sea water is approximately 8,2.
5.6 Recreational waters
Recreational waters are bathing, swimming pool, thermal bath and spa waters. They may be sourced
from natural waters or waters intended for human consumption and are characterized, in addition to
the influence parameters defined in 5.2, by the potential presence of specific disinfection products and
by-products, and the potential presence of sulfur compounds.
6 Selection of characteristic parameters of a matrix
6.1 General
For the purposes of characterization of the applicability and the performances of an analytical method
to a matrix, the laboratory shall describe the limits of the ranges associated with the characteristic
parameters discussed in this clause.
6.2 All waters
The parameters are those defined in 5.1.
6.3 Waters intended for consumption
In addition to the characteristics listed in 5.1, waters intended for consumption are characterized by:
— their free and total chlorine content;
— the nature and content of disinfection reagents and by-products;
— their CO content, if relevant.
Refer to Annex A for more detailed characterization of waters intended for human consumption.
6.4 Natural waters
In addition to the characteristics listed in 5.1, natural waters are characterized by:
— the sampling location, including the sampling depth;
— the identified surrounding anthropic pressures.
In the case of groundwater used as drinking water resources, which are treated in situ, free and total
chlorine content should be verified.
6.5 Waste waters
In addition to the characteristics listed in 5.1, waste waters are characterized by:
— the original activity sector (see Annex C);
— the connected activity sectors in the case of municipal waste water treatment plants (MWWTP)
discharges.
6.6 Marine waters
In addition to the characteristics listed in 5.1, marine waters are characterized by:
— the sampling location, including sampling depth;
— their salinity.
6.7 Recreational waters
In addition to the characteristics listed in 5.1, recreational waters are characterized by:
— the sampling location;
— the nature and content of disinfection reagents and by products.
7 Available materials
7.1 General
The laboratory shall select study matrices for one or more of the above water types from, in order of
preference:
— reference materials if the matrix is sufficiently characterized;
— supernumerary material from interlaboratory tests if stable and sufficiently characterized;
— material obtained by spiking with the real matrix free from the analytes of interest;
— material obtained by spiking a reasonable dilution of a real matrix, after adjusting the characteristics
modified by the dilution;
— material obtained by spiking of an artificial matrix based on a recipe (see Annex B).
At least three different representative samples of each water type should be studied to provide a
realistic evaluation of performance of the method on the selected water type. Wherever possible, the
method performances shall be characterized on a non-artificial sample.
7.2 Material obtained by reasonable dilution of a real matrix
When the laboratory cannot select a real matrix free from analyte(s) of interest, but it is possible to
select a real matrix containing the analyte(s) of interest at a concentration lower than 10× the limit
of quantification (LOQ) defined for the method under examination, a representative matrix can be
prepared by diluting the low-concentration real matrix, so as to lower the concentration of analyte(s) of
interest to less than the LOQ defined for the method.
The dilution factor, f, shall be lower than 10. For this dilution, a water free from analyte(s) of interest
having a similar composition to the chosen matrix (major elements and influence factors) shall be used.
Before dilution, the selected matrix shall be characterized on the basis of the influence parameters
chosen for the study. After dilution, these parameters shall be readjusted if required using solid state
reagents or stock solutions of solid state reagents so that the value of each influence parameter remains
within the scope defined by the laboratory.
8 © ISO 2019 – All rights reserved

7.3 Artificial material
Artificial materials can be prepared according to Annex B, after adjusting the influence parameters
selected based on a bibliographic study, and/or on Annex C, within the concentration range defining the
scope of the method.
7.4 Analyte-specific blank values in matrices
For some analytes, such as heavy metals, no analyte-free natural or artificial matrix can be obtained.
After proper justification, the laboratory should study LOQ as follows.
— Determine LOQ on ultrapure water.
MQ
— Calculate LOQ by correcting LOQ using the recovery of the analyte in the intended matric,
water i MQ
i.e. water by using Formula (1):
LOQ
MQ
LOQ = (1)
water i
ρ
water i
where
LOQ is the LOQ of the method for the analyte in water type i;
water i
LOQ is the LOQ of the method for the analyte in ultra pure water;
MQ
is the mean recovery of the method for the analyte in water type i.
ρ
water i
8 Report
The quantitative analytical method assessment report, for a given matrix, shall include, in addition to
the information requested by the assessment procedure:
a) the name of the tested matrix according to the typology defined in Clause 5;
b) the characteristic parameters of the matrix according to Clause 6 and the associated representative
ranges (scope);
c) the influence parameters tested, the justification for their selection and the representative
contents;
d) the source of the matrix and, if applicable, its preparation method.
Annex A
(informative)
Characterization of waters intended for human consumption and
mineral waters
Water intended for human consumption produced, is generally characterized by:
— the absence of suspended solids;
— a relatively low organic content (TOC < 4 mg/ l);
— a conductivity at 25 °C between 50 µS/cm and 1 100 µS/cm and
— a pH between 6 and 9.
Waters sampled during the production cycle, or at distribution point, often show traces of oxidants
used to disinfect resource water, usually chlorine, chlorine dioxide or ozone at levels between 0,2 mg/l
and 2 mg/l. Depending on the parameters to be analysed, it may be necessary to eliminate these
traces of oxidants by a neutralizing agent, usually sodium thiosulfate pentahydrate added to reach a
concentration between 20 mg/l and 200 mg/l.
The oxidant addition may also generate disinfection by-products, mainly trihalomethanes, bromates,
chlorates.
Mineral waters show generally the same figures, without addition of oxidant, but some of them are also
characterized by:
— high mineralization level (higher than 2 g/l);
— presence of carbon dioxide (sparkling waters), or
— presence of sulfides (thermal waters).
To select a representative model water for the validation of a method dedicated to the analysis of water
intended for human consumption, the data listed above, and, where their presence might influence
on the analytical protocol, the presence of ions representative of the catchment zone, nature and
concentration, according to the geological characteristics thereof is taken into account.
10 © ISO 2019 – All rights reserved

Annex B
(informative)
Examples of preparation of artificial matrices and representative
characteristics
B.1 Overview
This annex gives examples of formulae that may be used to prepare various water types in a reproducible
manner, to be used for the validation of analytical method.
NOTE In case of use for quality control (QC), suitable procedure for homogeneity and stability checking can
[19]
be found, if necessary, in ISO Guide 80 .
B.2 Equipment
B.2.1 Balance accurate to 1/10 mg.
B.2.2 Common laboratory glassware.
B.2.3 Non-actinic glassware for storage of stock solutions.
B.2.4 Flask with screw cap, for degassing beer.
B.2.5 Laboratory mixer, comprising an inert container and a lid, for waste water preparations.
B.3 Reagents
All reagents used for a formula should be of sufficient quality (at least “analysis quality”). Unless
otherwise indicated, water compliant to ISO 3696 shall be used to implement these formulae.
Some reagents are specific to one of the formulae.
B.3.1 Boric acid, H BO , anhydrous.
2 3
B.3.2 Nitric acid, HNO , c(HNO ) = 15,8 mol/l, ρ = 1,4 kg.
3 3
B.3.3 Ammonium chloride, NH Cl, anhydrous.
B.3.4 Potassium bromide, KBr, anhydrous.
B.3.5 Aluminium chloride hexahydrate, AlCl ·6H O.
3 2
B.3.6 Magnesium chloride hexahydrate, MgCl ·6H 0.
2 2
B.3.7 Anhydrous calcium chloride, CaCl .
B.3.8 Strontium chloride hexahydrate, SrCl ·6H 0.
2 2
B.3.9 Potassium chloride, KCl, anhydrous.
B.3.10 Sodium chloride, NaCl, anhydrous.
B.3.11 Sodium fluoride, NaF, anhydrous.
B.3.12 Sodium hydroxide, NaOH, solution 0,10 mol/l.
B.3.13 Sodium hydrogen carbonate, NaHCO , anhydrous.
B.3.14 Barium nitrate, Ba(NO ) , anhydrous.
3 2
B.3.15 Manganese nitrate hexahydrate, Mn(NO ) ·6H O.
3 2 2
B.3.16 Copper nitrate trihydrate, Cu(NO ) ·3H O.
3 2 2
B.3.17 Zinc nitrate hexahydrate, Zn(NO ) ·6H O.
3 2 2
B.3.18 Lead nitrate, Pb(NO ) , anhydrous.
3 2
B.3.19 Potassium acid phosphate, (KH PO ), anhydrous.
2 4
B.3.20 Sodium sulfate, Na SO , anhydrous.
2 4
B.3.21 Ferric sulfate, Fe(SO ) , anhydrous.
4 3
B.3.22 Magnesium sulfate, Mg SO , anhydrous.
2 4
B.3.23 Urea, (NH ) CO.
3 2
B.3.24 Kaolin.
Argillaceous rock containing kaolinite, hydrous aluminium silicate (2SiO , Al O , 2H O). This rock is
2 2 3 2
friable, impermeable and refractory.
B.3.25 Degassed beer. Industrially produced commercial drink, obtained by fermenting a mixture of
cereal grains, malt and hops. “Low-calorie” quality (<1 180 J/ml).
Transfer the beer into a closed container with capacity 20 % greater than the quantity of beer to be
degassed. Close, shake vigorously, then release the pressure by slightly loosening the cap. Leave to rest
in the refrigerator for 24 h.
Bring to ambient temperature before use.
B.3.26 Microcrystalline cellulose, dried to constant mass at 105 °C and kept in a desiccator.
B.3.27 Dry salt for marine aquarium.
A commercial mixture of mineral salts for marine aquariums, such as sold in pet shops for example,
dried to constant mass at 105 °C and kept in a desiccator.
B.3.28 Yeast, Saccharomyces cerevisiae, also called baker's yeast, fresh.
12 © ISO 2019 – All rights reserved

B.3.29 Peptone.
An animal protein digestate used in the preparation of biological culture media, containing ≥12 %
nitrogen.
B.4 Marine waters
B.4.1 General
These formulae enable preparation of a solution containing mineral salts in comparable proportions to
a sea water, corresponding to a typical heavy metal-enriched sea water, that is reproducible and usable
when it is necessary to simulate a marine water.
Preparation of stock solutions is required.
B.4.2 Stock solutions
B.4.2.1 Stock solution No. 1
In a 1 l volumetric flask, place 500 ml of water. Dissolve:
MgCl ·6H 0: 555,6 g
2 2
CaCl : 57,9 g
SrCl ·6H O: 2,1 g
2 2
Adjust to 1 l with water. Store in a carefully stoppered amber glass flask.
B.4.2.2 Stock solution No. 2
In a 1 l volumetric flask, place 500 ml of water. Dissolve:
KCl: 69,5 g
NaHCO : 20,1 g
KBr: 10,0 g
H BO : 2,7 g
3 3
NaF: 0,3 g
Adjust to 1 l with water. Store in a carefully stoppered amber glass flask.
B.4.2.3 Stock solution No. 3
In a 1 l volumetric flask, place 500 ml of water. Dissolve:
Ba(NO ) : 0,994 g
3 2
Mn(NO ) ·6H O: 0,546 g
3 2 2
Cu(NO ) ·3H O: 0,396 g
3 2 2
Zn(NO ) ·6H O: 0,151 g
3 2 2
Pb(NO ) : 0,066 g
3 2
Adjust to 1 l with water. Store in a carefully stoppered amber glass flask.
NOTE Larger quantities of stock solutions can be prepared by proportionally adapting the above
formulations.
B.4.3 Preparation
[7], [10]
B.4.3.1 Artificial marine water
In a 1 l volumetric flask, place 800 ml of water. Dissolve:
NaCl: 24,534 g
Anhydrous Na SO : 4,094 g
2 4
Add 20 ml of stock solution No. 1 and 10 ml of stock solution No. 2. Shake vigorously. Adjust to 1 l. Adjust
the pH to 8,2 with a few drops of 0,1 N sodium hydroxide solution (B.3.12).
The artificial marine water thus prepared has the following composition:
Concentration (g/l)
NaCl: 24,534
Na SO : 4,09
2 4
KCl: 0,695
NaHCO : 0,201
KBr: 0,100
H BO : 0,027
3 3
NaF: 0,030
MgCl : 5,20
CaCl : 1,16
SrCl : 0,025
This preparation should be used immediately after preparation.
[11]
B.4.3.2 Heavy metal-enriched artificial marine water
Add 1 ml of stock solution No. 3 to 1 l of artificial marine water (B.4.2.1).
The heavy metal-enriched artificial marine water thus prepared has the following composition:
Concentration (g/l)
NaCl: 24,534
Na SO : 4,09
2 4
KCl: 0,695
NaHCO : 0,201
14 © ISO 2019 – All rights reserved

KBr: 0,100
H BO : 0,027
3 3
NaF: 0,030
MgCl : 5,20
CaCl : 1,16
SrCl : 0,025
Ba(NO ) : 0,000 994
3 2
Mn(NO ) ·6H O: 0,000 546
3 2 2
Cu(NO ) ·3H O: 0,000 396
3 2 2
Zn(NO ) ·6H O: 0,000 151
3 2 2
Pb(NO ) : 0,000 066
3 2
This formula should be used immediately after preparation.
[15]
B.4.3.3 Artificial marine water as per Kester
Dissolve in 750 ml of distilled water:
Compound NaCl Na S0 KCl NaHC0 KBr H BO NaF
2 4 3 3 3
Mass (g) 23,926 4,008 0,677 0,196 0,098 0,026 0,003
Add:
a
Solution Volume (ml)
−1
MgCl ·6 H 0: 1 mol·l 53,27
2 2
−1
CaCl ·2 H 0: 1 mol·l 10,33
2 2
−1
SrCl ·6 H 0: 0,1 mol·l 0,90
2 2
a
Solutions with precise concentrations of silver nitrate.
Make up to 1 kg with distilled water.
This water has a salinity of 35,00 g/kg.
[15], [16]
B.4.3.4 Controlled-salinity artificial marine waters as per Grasshoff
B.4.3.4.1 Artificial marine water as per Grasshoff — Formula 1
Dissolve in 500 ml of distilled water (solution G1a):
Compound NaCl Na S0 KCl NaHC0 KBr H BO NaF
2 4 3 3 3
Mass (g) 23,9 4,0 0,7 0,2 0,1 0,03 0,003
Dissolve in 455 ml of distilled water (solution G1b):
Compound MgCl ·6 H O CaCl ·2H O SrCl ·6H O
2 2 2 2 2 2
Mass (g) 10,8 1,5 0,025
Mix solutions G1a and G1b, measure the salinity of the mixture (S approximately 35).
B.4.3.4.2 Artificial marine water as per Grasshoff — Formula 2
Dissolve in approximately 800 ml of distilled water:
Compound NaCl NaHCO MgS0 ·7 H 0
3 4 2
Mass (g) 32 0,2 14
Make up to 1 l with distilled water: salinity is equal to 34,2 (chlorosity = 19,4 g/l).
B.5 Waste waters
B.5.1 General
Waste waters can have very variable compositions depending on their source. The formulations
suggested below contain compounds in concentrations such as those that can be found in treated
urban waste water discharges. They are not intended to represent all waste waters, but can provide a
laboratory material enabling assessment of the initial performances and performances over time of the
analytical methods on a reproducible and inexpensive material.
If the laboratory wishes to refine the prepared material in order to adapt its representativeness to
certain types of discharges, it may select the relevant substances or interfering substances using the
substance lists provided in Annex C.
[9]
B.5.2 WWTP water
Place approximately 500 ml of water in the container of the mixer. Set the mixing speed to the lowest.
Add in this order:
Microcrystalline cellulose (B.3.26): 0,400 g
Dry salt for marine aquarium (B.3.27): 2,000 g
Kaolin (B.3.24): 0,080 g
Degassed beer (B.3.25): 120,0 ml
Mix for 30 s. Transfer quantitatively to a 2 l volumetric flask and adjust.
16 © ISO 2019 – All rights reserved

This solution may be kept in the refrigerator for 24 h. Preservative additives described in ISO 5667-3
should be added depending on the analytical method to be assessed.
The typical characteristics of this effluent are listed in Tables B.1 and B.2.
B.5.3 Discharge water
B.5.3.1 Source of the formula
This formula has been used by INERIS since 2005 (see Reference [17]). The values have been chosen
regarding applicable national French regulation setting the technical requirements relating to
collection and waste water treatment plans:
— suspended solids are represented by microcrystalline cellulose in the proportion of 250 mg/l;
— the total nitrogen content of 10 mg/l will be obtained using a mixture of urea and ammonium
chloride;
— the total phosphorus content of 1 mg/l will be obtained using KH PO .
2 4
Aluminium and iron are not part of the monitoring of discharge waters and do not appear in the
IOW databases (International Office for Water). On the other hand, they are regularly present in
interlaboratory test materials, for example those supplied by AGLAE (General Association of Analysis
and Testing Laboratories). Based on the study of contents between June 2003 and May 2004, a typical
content of 200 µg/l for each of these is proposed, expressed as total metal, for a given range of:
Al (µg/l): 170 to 775
Fe (µg/l): 130 to 590
As this model is intended for studying the performances of methods in a limited catchment area or
in a specific industrial sector, it is always created based on drill water or water for consumption in
the geographical area concerned; this is why only anthropogenic parameters are adjusted by means of
reagents. Its composition in terms of main elements is to be recorded.
B.5.3.2 Preparation
Place approximately 500 ml of water in the container of the mixer. Set the mixing speed to the lowest.
Add in this order:
Microcrystalline cellulose (B.3.26) 500 mg
Urea (B.3.23) and ammonium chloride (B.3.3) Equiv 20 mg nitrogen each
KH PO (B.3.19) Equiv 2 mg phosphorus
2 4
AlCl ·6H O (B.3.5) Equiv 400 µg aluminium
3 2
Fe(SO ) (B.3.21) Equiv 400 µg iron
4 3
Mix for 30 s. Transfer quantitatively to a 2 l volumetric flask and adjust. Check the characteristic
parameters of the prepared effluent; adjust if necessary using the reagents above.
This solution may be kept in the refrigerator for 24 h. Preservative additives described in ISO 5667-3
should be added depending on the analytical method to be assessed.
The typical characteristics of this effluent are listed in Tables B.1 and B.2.
[12]
B.5.4 Artificial effluent 1
To 1 l of deionized water, add:
Compound Microcrystalline Urea Yeast NaCl K HPO CaCl MgSO
2 4 2 4
cellulose
QS 0,400 g/l 0,03 g/l 0,11 g/l 0,007 g/l 0,028 g/l 0,028 g/l 0,028 g/l
Mix and check the characteristic parameters of the prepared effluent; adjust if necessary using the
reagents above.
The typical characteristics of this effluent are listed in Tables B.1 and B.2.
This solution should be prepared daily. Preservative additives described in ISO 5667-3 should be added
depending on the analytical method to be assessed.
[11]
B.5.5 Artificial effluent 2
To 1 l of deionized water, add:
Compound Peptone Urea Yeast NaCl K HPO CaCl MgSO
2 4 2 4
QS 0,16 g/l 0,03 g/l 0,11 g/l 0,007 g/l 0,028 g/l 0,028 g/l 0,028 g/l
1)
NOTE 0,9 ml of the food product Viandox® can replace the peptone. Before dilution, it has the following
+ 3-
characteristics: COD: 260 g/l, BOD: 155 g/l, Kjeldahl nitrogen: 26 g/l, NH : 7 g/l PO : 3,6 g/l (see References [12]
4 4
and [14]).
The typical characteristics of this effluent are listed in Table B.1.
Check the characteristic parameters of the prepared effluent; adjust if necessary using the reagents above.
This solution should be prepared daily. Preservative additives described in ISO 5667-3 should be added
depending on the analytical method to be assessed.
[13]
B.5.6 Artificial effluent 3
A commercial mixture comprising meat, vegetable extracts and sugars (Viandox®) can constitute an
anthropogenic model of dissolved organic matter. It contains 42 g/l carbohydrates, 173 g/l protein, and
0,77 mg/l fat (see Reference [14]).
Artificial waste water can be prepared based on Viandox®, by diluting at 1 % in mineral water.
Dissolved organic matter is simulated by 1 g of yeast.
The typical characteristics of this effluent are listed in Tables B.1 and B.2.
Check the characteristic parameters of the prepared effluent; adjust if necessary using the reagents
in B.4.1.
This solution should be prepared daily. Preservative additives described in ISO 5667-3 should be added
depending on the analytical method to be assessed.
B.5.7 Typical values of the characteristic parameters of waste water formulae
The typical values of the characteristic parameters of the waste water formulae described in B.5
were measured on formulae that were reconstituted based on water for consumption distributed in
1) Viandox® is an example of a suitable product available commercially, solution of a product similar to OXO®,
VEGEMITE®, or BOVRIL®. This examp
...