oSIST prEN 1302:2023
(Main)Chemicals used for treatment of water intended for human consumption - Aluminium-based coagulants - Analytical methods
Chemicals used for treatment of water intended for human consumption - Aluminium-based coagulants - Analytical methods
This document is applicable to aluminium-based coagulants used for treatment of water intended for human consumption. It specifies analytical methods to be used for products described in EN 878, EN 882, EN 885, EN 886, EN 887, EN 935 and EN 17034.
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch - Flockungsmittel auf Aluminiumbasis - Analytische Methoden
Dieses Dokument gilt für Flockungsmittel auf Aluminiumbasis zur Aufbereitung von Wasser für den menschlichen Gebrauch. Es legt die zu verwendenden analytischen Methoden für die Produkte fest, die in EN 878, EN 882, EN 885, EN 886, EN 887, EN 935 und EN 17034 beschrieben sind.
Produits chimiques utilisés pour le traitement de l'eau destinée à la consommation humaine - Coagulants à base d'aluminium - Méthodes d'analyse
Le présent document est applicable aux coagulants à base d’aluminium utilisés pour le traitement de l’eau destinée à la consommation humaine. Il spécifie les méthodes d’analyse à utiliser pour les produits décrits dans les normes EN 878, EN 882, EN 885, EN 886, EN 887, EN 935 et EN 17034.
Kemikalije, ki se uporabljajo za pripravo pitne vode - Koagulanti na osnovi aluminija - Analitske metode
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 1302:2023
01-julij-2023
Kemikalije, ki se uporabljajo za pripravo pitne vode - Koagulanti na osnovi
aluminija - Analitske metode
Chemicals used for treatment of water intended for human consumption - Aluminium-
based coagulants - Analytical methods
Produkte zur Aufbereitung von Wasser für den menschlichen Gebrauch -
Flockungsmittel auf Aluminiumbasis - Analytische Methoden
Produits chimiques utilisés pour le traitement de l'eau destinée à la consommation
humaine - Coagulants à base d'aluminium - Méthodes d'analyse
Ta slovenski standard je istoveten z: prEN 1302
ICS:
13.060.20 Pitna voda Drinking water
71.100.80 Kemikalije za čiščenje vode Chemicals for purification of
water
oSIST prEN 1302:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 1302:2023
DRAFT
EUROPEAN STANDARD
prEN 1302
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2023
ICS 71.100.80 Will supersede EN 1302:1999
English Version
Chemicals used for treatment of water intended for human
consumption - Aluminium-based coagulants - Analytical
methods
Produits chimiques utilisés pour le traitement de l'eau Produkte zur Aufbereitung von Wasser für den
destinée à la consommation humaine - Coagulants à menschlichen Gebrauch - Flockungsmittel auf
base d'aluminium - Méthodes d'analyse Aluminiumbasis - Analytische Methoden
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 164.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1302:2023 E
worldwide for CEN national Members.
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prEN 1302:2023 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Methods of analysis . 5
5 Sampling . 7
6 Expression of results . 8
6.1 Aluminium content. 8
6.2 Iron . 8
6.3 Sodium, calcium, chloride, sulfate and silicate . 8
6.4 Free acid . 8
6.5 Basicity . 8
6.6 Insoluble matters . 8
6.7 Chemical parameters. 8
6.8 Repeatability . 8
Annex A (normative) Analysis of aluminium content . 9
Annex B (normative) Analysis of chemical parameters and impurities . 15
Annex C (informative) Routine methods . 37
Bibliography . 56
2
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prEN 1302:2023 (E)
European foreword
This document (prEN 1302:2023) has been prepared by Technical Committee CEN/TC 164 “Water
supply”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 1302:1999.
In comparison with the previous edition, the following technical modifications have been made:
— Replacement of the withdrawn aluminium product standards EN 881 and EN 883 by EN 17034.
— Replacement of the withdrawn mercury analysing standard ISO 5666-1:1983 by ISO 12846:2012.
— Removal of the withdrawn standard ISO 6382:1981. As there was no replacement, the analysing
method for silicon content based on this standard was removed.
— Removal of routine methods used for determinate arsenic. Method: Silver diethyldithiocarbamate
spectrophotometric method based on standard ISO 6595:1982 as this standard has been
withdrawn without replacement.
— Removal of routine methods used for determinate iron. Method: 1,10-Phenanthroline
spectrophotometric method based on standard ISO 6685:1982 as this standard has been
withdrawn without replacement.
2+
— Removal of a method for determination of iron (total and Fe ) (volumetric method) as EN 5790
has been removed as the standard has been withdrawn without replacement. Furthermore, the
method uses potassium dichromate and there are other options for iron determination.
— Update of the clause titles to correspond the CEN Standard form.
— Update of Table 1 and 2 to correspond the analytical methods available in the standard.
3
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1 Scope
This document is applicable to aluminium-based coagulants used for treatment of water intended for
human consumption. It specifies analytical methods to be used for products described in EN 878,
EN 882, EN 885, EN 886, EN 887, EN 935 and EN 17034.
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.
EN 878, Chemicals used for treatment of water intended for human consumption - Aluminium sulfate
EN 882, Chemicals used for treatment of water intended for human consumption - Sodium aluminate
EN 885, Chemicals used for treatment of water intended for human consumption - Polyaluminium chloride
hydroxide silicate
EN 886, Chemicals used for treatment of water intended for human consumption - Polyaluminium
hydroxide silicate sulfate
EN 887, Chemicals used for treatment of water intended for human consumption - Aluminium iron (III)
sulfate
EN 935, Chemicals used for treatment of water intended for human consumption - Aluminium iron(III)
chloride (monomeric) and aluminium iron(III) chloride hydroxide (monomeric)
EN 17034, Chemicals used for treatment of water intended for human consumption - Aluminium chloride
anhydrous, aluminium chloride basic, dialuminium chloride pentahydroxide and aluminium chloride
hydroxide sulfate
EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696)
ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic
method for the determination of repeatability and reproducibility of a standard measurement method
ISO 6227:1982, Chemical products for industrial use — General method for determination of chloride ions
— Potentiometric method
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
laboratory sample
sample as prepared for sending to the laboratory and intended for inspection or testing
[SOURCE: ISO 6206:1979]
4
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3.2
test sample
sample prepared from the laboratory sample and from which test portions will be taken
[SOURCE: ISO 6206:1979]
3.3
test portion
quantity of material drawn from the test sample (or from the laboratory sample if both are the same)
and on which the test or observation is actually carried out
[SOURCE: ISO 6206:1979]
4 Methods of analysis
The methods of analysis are used to analyse the product quality. Table 1 lists the methods which shall
be used for analysis of aluminium-based coagulants composition as commercial product and the
principles of each method. The reference methods which shall be used are described in full in
Annexes A and B. Other methods can be used for quality control.
Table 2 lists the methods which shall be used for analysis of main by-products and chemical
parameters. These are applicable to all aluminium based coagulants (EN 878, EN 882, EN 885, EN 886,
EN 887, EN 935 and EN 17034). The relevant limit value for each coagulant is available in the product
standard.
5
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Table 1 — Methods of analysis of the composition of commercial product
Reference Informative
Determination EN 878 EN 882 EN 885 EN 886 EN 887 EN 935 EN 17034 Principle Annex
method method
a
x x x x x x x EDTA complexometric titration A.1
Aluminium
b
Aluminium x x x x x x CDTA complexometric titration Annex A
x
Aluminium x x Gluconate A.2
Iron x x x x x x x x ICP-OES B.8
Iron x x x x x x x x FAAS A.1
c
Iron
x x x x x x x x ICP-MS
Sodium x x x x x x x ICP-OES B.8
Sodium x x x AAS A.1
Sodium x x Gluconate A.2
Calcium x x x x AAS A.1
Calsium x x x x ICP-OES B.8
Chloride x x x x Potentiometric titration B.1
Sulfate x x x x x Barium sulfate gravimetry B.2
Free acid x x x x Acidimetric titration B.4
Basicity x x x x x x Acidimetric titration, oxalate method B.5
Basicity x x Acidimetric titration, KF method B.6
Basicity x Calculation method C.7
Key
AAS: Atomic Absorption Spectrometry
AFS: Atomic Fluorescence Spectrometry
ICP-OES: Inductively Coupled Plasma Optical Emission Spectrometry
ICP-MS: Inductively Coupled Plasma Mass Spectrometry
a
Only applicable for determination of aluminium if iron content is lower than 1,6 g Fe per kilogram of aluminium.
b
The reference method when iron content is higher than 1,6 g Fe per kilogram of aluminium.
c
This document does not give a description for this method of analysis.
6
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Table 2 — Applicability methods of analysis to main by-products and chemical parameters
Reference Routine
Determination Principle
method method
Insoluble matter B.7 Gravimetry
Arsenic B.8 ICP-OES
C.3 ICP-MS
x AAS
Cadmium B.8 ICP-OES
C.3 ICP-MS
x AAS
Chromium B.8 ICP-OES
x ICP-MS
x AAS
Mercury B.10 AAS (cold vapour)
B.9 AFS
Nickel B.8 ICP-OES
x ICP-MS
x AAS
Lead B.8 ICP-OES
C.3 ICP-MS
x AAS
Antimony B.8 ICP-OES
C.3 ICP-MS
x AAS
Selenium B.8 ICP-OES
C.3 ICP-MS
x AAS
Key
AAS: Atomic Absorption Spectrometry
AFS: Atomic Fluorescence Spectrometry
ICP-OES: Inductively Coupled Plasma Optical Emission Spectrometry
ICP-MS: Inductively Coupled Plasma Mass Spectrometry
5 Sampling
Sampling methods are mentioned in the product standards (EN 878, EN 882, EN 885, EN 886, EN 887,
EN 935 and EN 17034). Choose the relevant sampling method.
From the laboratory sample, prepare the test sample by grinding the solid samples until the particle
size is below 2,5 mm and homogenizing, and homogenize the liquid samples.
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6 Expression of results
6.1 Aluminium content
The aluminium content shall be expressed as aluminium mass fraction in % or as Al in grams per kg of
product.
6.2 Iron
The iron content shall be expressed as iron mass fraction in % or ar Fe in grams per kg of product
depending on analytical method.
6.3 Sodium, calcium, chloride, sulfate and silicate
The sodium, calcium, chloride or sulfate content shall be expressed as grams of substance per kilogram
of product or as mass fraction in % depending on analytical method.
6.4 Free acid
Free acid shall be expressed as in grams of sulfuric acid per kilogram of product (H SO g/kg) or in
2 4
grams of hydrochloric acid per kilogram of product (HCl g/kg).
6.5 Basicity
–
The basicity shall be expressed in grams of hydroxide per kilogram of product (OH g/kg) or as the
–
relative basicity expressed in moles of OH per moles of Al (OH/Al) or as in % (OH/AL *100/3).
6.6 Insoluble matters
Insoluble matters shall be expressed in mass fraction in % or in grams per kilogram of product.
6.7 Chemical parameters
The chemical parameters mentioned in Table 2 shall be expressed as milligrams of element per
kilogram of product.
6.8 Repeatability
Each laboratory shall calculate the repeatability of the method under their laboratory conditions
according to the procedure defined in ISO 5725-2.
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Annex A
(normative)
Analysis of aluminium content
A.1 Determination of aluminium (EDTA complexometric method)
A.1.1 General
This method shall be used for the determination of aluminium in aluminium-based coagulants used for
treatment of water intended for human consumption:
— as the reference method for products with iron content lower than 1,6 g of Fe per kilogram of
aluminium e.g. described in EN 878 (iron free grade), EN 882 and applicable for the other standards
if Fe content is low;
— as a routine method for products described in EN 878 (low iron grade), EN 885, EN 886, EN 935
and EN 17034 containing no more than 10 g of Fe per kilogram of aluminium.
A.1.2 Principle
Dissolution in water, in the case of solid products, or dilution with water in the case of products in
solution, of a test sample.
Complexation of aluminium, in a hot acidic medium with an excess of ethylenediaminetetraacetic acid
(EDTA) solution. Titration of the excess EDTA with a standard volumetric solution of zinc in the
presence of xylenol orange as indicator.
3+
Al + EDTA 4- –> AlEDTA -
4- 2-
Zn2+ + EDTA –> ZnEDTA
A.1.3 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to grade 3 in
accordance with EN ISO 3696.
A.1.3.1 Sodium acetate solution, 80 g/l.
A.1.3.2 Sodium hydroxide solution, 100 g/l.
A.1.3.3 Hydrochloric acid
Dilute one volume of hydrochloric acid (p = 1,19 g/ml) with one volume of water.
A.1.3.4 Hydrochloric acid, 36,5 g/l, c(HCl) = 1 mol/l.
A.1.3.5 Disodium ethylenediaminetetraacetate dihydrate (NaEDTA), standard volumetric solution,
c(C H N O Na .2H O) = 0,05 mol/l. Weigh to the nearest 0,000 1 g, 18,625 g of NaEDTA. Dissolve
10 14 2 8 2 2
in water, transfer the solution quantitatively to a 1 000 ml volumetric flask. Dilute to volume with water
and homogenize.
NOTE Commercial standard volumetric solution could be used.
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A.1.3.6 Zinc, standard volumetric solution, c(Zn) = 0,05 mol/l. Weigh to the nearest 0,000 1 g,
6,537 0 g (m)of pure zinc (minimum content 99,9 % (m/m)).
Dissolve in 60 ml of hydrochloric acid solution (A.1.3.3). During the reaction, cover the beaker with a
watch-glass. At the end of the reaction, boil the solution for 10 min, then cool to room temperature.
Dilute to about 500 ml with water and add sodium acetate solution (A.1.3.1) until a pH of 5,5 ± 0,1 is
obtained. Transfer the solution quantitatively to a 2 000 ml volumetric flask. Dilute to volume with
water and homogenize.
NOTE 1 If the mass of zinc is not exactly that stated above, the zinc concentration is given by the equation:
m
c(Zn)=
2×65,37
where
m is the mass in grams of zinc weighed;
65,37 is the relative molecular mass of zinc;
c(Zn) is the concentration of zinc solution, in moles per litre, calculated to the fourth
significant figure.
NOTE 2 Commercial standard solution could be used.
A.1.3.7 Buffer solution, pH 5,5.
Weigh 50 g of sodium acetate trihydrate (CH COONa.3H O). Dissolve in 500 ml of water and add glacial
3 2
acetic acid (CH COOH) until a pH of 5,5 ± 0,1 is obtained.
3
A.1.3.8 Xylenol orange.
Grind 1,0 g of xylenol orange with 99 g of potassium nitrate in a mortar until a homogeneous mass is
obtained.
A.1.4 Apparatus
Ordinary laboratory apparatus and glassware, and optionally:
A.1.4.1 Automatic titrator and photometer with fibre optic probe.
A.1.4.2 Microwave equipment.
A.1.5 Procedure
A.1.5.1 Preparation of the test solution
Weigh, to the nearest 0,001 g, about 25 g of the test sample (m ) into a 400 ml beaker.
0
Add approximately 150 ml of water at 80 °C to 90 °C. Stir until dissolved, using a glass stirrer.
Transfer quantitatively to a 500 ml volumetric flask. Dilute to volume with water and homogenize.
Filter if necessary through a filter paper (particle retention size 2,5 μm) (test solution V ).
0
10
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Place V ml of this solution (see Table A.1) into a 200 ml volumetric flask. Dilute to volume with water
1
and homogenize (diluted test solution V ).
2
Table A.1 — Aliquot portion V for Al determination (EDTA method)
1
Volume V
Expected content
1
Al g/kg ml
< 27 100
27 to 66 50
66 to 133 20
133 to 265 10
A.1.5.2 Blank test
Perform a blank test following the same procedure and using the same quantities of all the reagents as
indicated in A.1.5.3. Record the volume used for the titration (V ).
5
A.1.5.3 Determination
Transfer 100,0 ml of solution (A.1.5.1) (V ) to a 250 ml beaker and adjust to pH 5 to 6 with hydrochloric
3
acid solution (A.1.3.3) or sodium hydroxide solution (A.1.3.2). Add 5 ml of hydrochloric acid
solution (A.1.3.4) and 50,0 ml of the standard volumetric solution of EDTA (A.1.3.5). Cover with a watch
glass. Heat the solution at 80 °C to 90 °C for at least 20 min. Cool to room temperature. Rinse the watch
glass with water into the beaker. Neutralize with sodium acetate solution (A.1.3.1). The pH value shall
be between 7 to 7,5 and add 10 ml of the buffer solution (A.1.3.7).
Add 30 mg to 50 mg of xylenol orange mixture (A.1.3.8). Titrate with the standard volumetric zinc
solution (A.1.3.6) until the indicator changes from yellow to definite red or determine the equivalence
point using an automatic titrator. Record the volume (V ) used.
4
If microwave equipment (A.1.4.2) is used, the volume V and the volume of the aliquot portion (A.1.5.1)
1
can be different from those indicated above. Transfer the test portion to a 250 ml conical flask and
adjust to pH 5 to 6 with hydrochloric acid (A.1.3.3) or sodium hydroxide solution (A.1.3.2). Add 5 ml of
hydrochloric acid solution (A.1.3.4) and the suitable volume of the standard volumetric solution of
EDTA (A.1.3.5). Transfer to the microwave equipment. Operate the microwave equipment at a power
setting to achieve a temperature at 80 °C to 90 °C for 15 min. Then cool to room temperature. Transfer
quantitatively to a 250 ml beaker or to the automatic titration cell.
If an automatic titrator (A.1.4.1) is used, the volume of the aliquot portion (A.1.5.1) and the volumes of
the reagents can be different from those indicated above. They should be such that the required
precision is achieved.
A.1.6 Expression of results
The aluminium content, X expressed in grams of aluminium per kilogram of product (Al g/kg) is given
1
by the equation:
V V 1 000
2 0
X 0,026 98× V−V×c×××
( )
1 54
VV m
31 0
11
=
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where
m is the mass, in grams, of the test sample;
0
V is the volume, in millilitres, of the test solution;
0
V is the volume, in millilitres, of test solution diluted to V ;
1 2
is the volume, in millilitres, of the diluted test solution;
V
2
V is the volume, in millilitres, of the aliquot for the determination;
3
V is the volume, in millilitres, of the standard volumetric solution of zinc used for the
4
titration of the sample test;
V is the volume, in millilitres, of the standard volumetric solution of zinc used for the
5
titration of the blank test;
c is the actual concentration, in moles per litre, of the standard volumetric solution of
zinc;
0,02698 is the mass of Al, in grams, corresponding to 1 ml of standard volumetric solution of
zinc, c(Zn) = 1 mol/l.
with V = 500 ml, V = 200 ml, V = 100 ml:
0 2 3
V −V ×c
( )
54
X 26 980×
1
Vm
10
A.2 Determination of aluminium and sodium in sodium aluminate
A.2.1 General
This method shall be used for determination of Na and Al in sodium aluminate.
If the carbonate content is high the calculated sodium content shall be corrected (A.2.2.2).
The measuring range of this method is 2-30 % Na and 2 %–30 % Al.
A.2.2 Principle
A.2.2.1 General
The composition of sodium aluminate solutions can be written:
NaAl(OH) + a NaOH (excess) + b Na CO .
4 2 3
Sodium and aluminium are determined by titration methods:
A.2.2.2 Determination of sodium
Gluconate is added and after that the solution is titrated to pH 9,0 with hydrochloric acid. When the
gluconate is added the following reaction takes place:
NaAl(OH) + n Gl → Al(OH) Gl + NaOH
4 3 n
When the pH is lowered to 9,0 the carbonate is mainly transformed to hydrogen carbonate:
Na CO + H O → NaHCO + NaOH
2 3 2 3
The total amount of acid used in the titration thus is:
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=
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1 + a + b mole HCl/mole Al = 1 + a + 2b mole Na/mole Al
A.2.2.3 Determination of aluminium
Potassium fluoride is added to the titrated solution from a):
– +
Al(OH) Gln + 6 KF →
K AlF + 3 OH + 3 K + n Gl
3
3 6
An excess of hydrochloric acid is added and back titration to the pH 9,0 is carried out with sodium
hydroxide. Three moles of acid consumed are thus equivalent to one mole of Al.
A.2.3 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to grade 1 in
accordance with EN ISO 3696.
A.2.3.1 Hydrochloric acid, HCl, 0,2 mol/l, ampoule.
A.2.3.2 Sodium hydroxide, NaOH, 0,2 mol/l, ampoule.
A.2.3.3 Sodium gluconate, C H (OH) COONa.
5 6 5
A.2.3.4 Sodium gluconate solution, 200 g/l.
Dissolve 40 g sodium gluconate (A.2.3.3) in 200 ml water. Adjust the solution to pH 9,0. Add 5 drops of
phenolphthalein solution (A.2.3.7). Store the solution in a plastic bottle.
A.2.3.5 Potassium fluoride, KF, pa.
A.2.3.6 Potassium fluoride (KF) solution, 3,5 mol/l.
Dissolve 200 g KF (A.2.3.5) in water up to 1000 ml and adjust pH to 8,9. Fluoride ions react with glass,
therefore store this solution in a plastic bottle.
A.2.3.7 Phenolphthalein solution, 0,5 g in 100 ml ethanol.
A.2.4 Apparatus
A.2.4.1 pH meter
A.2.4.2 Balance
Balance capable of weighing accurately 1 mg.
A.2.5 Procedure
A.2.5.1 Sample solution
Weigh 0,5xx to 0,6xx grams homogenized liquid sample or 0,25x to 0,3xx grams solid sample in
a 250 ml beaker. Add about 50 ml water and stir. This is the sample solution.
A.2.5.2 Determination
Analysis of the Na content
Add 15 ml of sodium gluconate solution (A.2.3.4) and 3 to 5 drops of the phenolphthalein solution
(A.2.3.7) to the sample solution (A.2.5.1).
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Titrate immediately the solution with hydrochloric acid (A.2.3.1) to pH 9,0. Record the volume, V .
1
Continue using this solution when analysing the Al content.
Analysis of the Al content.
Continue with the sample from the analysis of the Na content and add 15 ml of KF solution (A.2.3.6).
Titrate immediately and quickly the solution with hydrochloric acid (A.2.3.1) until the colour has
disappeared and add an excess of 5 to 6 ml of hydrochloric acid (A.2.3.1). Record the total volume, V .
2
Titrate immediately the solution with sodium hydroxide (A.2.3.2) to pH 9,0. Record the volume, V .
3
A.2.6 Calculation and expression of results
The sodium content X and the aluminium content Y, expressed in weight % of product (%), are given by
the equations:
Vc× ×23,00×100
11
X % Na
m×1 000
% Na O = 1,348 × % Na
2
(V ×c )−×Vc ×26,98×100
( )
2 1 3 2
Y % Al
m×3×1 000
% Al O = 1,890 × % Al
2 3
where
V is the volume of HCl in ml;
1
c is the concentration of HCl in mole/l;
1
V is the volume of HCl in ml;
2
V is the volume of NaOH in ml;
3
c is the concentration of NaOH in mole/l;
2
m is the mass of sample in grams.
14
==
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oSIST prEN 1302:2023
prEN 1302:2023 (E)
Annex B
(normative)
Analysis of chemical parameters and impurities
B.1 Determination of chloride (potentiometric method)
B.1.1 General
This method shall be used for the determination of chloride in aluminium-based coagulants used for
treatment of water intended for human consumption, as the reference method for products described
in EN 881, EN 885, EN 935 and EN 17034.
B.1.2 Principle
Dissolution in water, in the case of solid products, or dilution with water, in the case of products in
solution of a test sample.
Potentiometric titration with silver nitrate, in an acetone and water medium to reduce the solubility of
silver chloride:
- +
Cl + Ag –-> Ag Cl
B.1.3 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to grade 3 in
accordance with EN ISO 3696.
Use the reagents described in ISO 6227:1982 Clause 4.
B.1.4 Apparatus
Use the apparatus described in ISO 6227:1982 Clause 5.
B.1.5 Procedure
B.1.5.1 Preparation of the test solution
Weigh, to the nearest 0,001 g, about 25 g of the test sample (m ) into a 400 ml beaker.
0
Add approximately 150 ml of water at 80 °C to 90 °C. Stir until dissolved, using a glass stirrer.
Transfer quantitatively to a 500 ml volumetric flask. Dilute to volume with water and homogenize.
).
Filter if necessary through a filter paper (particle retention size 2,5 μm) (test solution V
0
B.1.5.2 Blank test
Perform a blank test following the same procedure and using the same quantities of all the reagents as
indicated in B.1.5.3.
B.1.5.3 Determination
If necessary, dilute the test solution as indicated in Table B.1.
Pipette the volume (V ) of solution or of diluted solution indicated in Table B.1.
3
Proceed as described in ISO 6227:1982 Clause 6.
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oSIST prEN 1302:2023
prEN 1302:2023 (E)
-
Table B.1 — Dilutions and aliquot portion V for Cl determination
3
-
Corresponding
in
Expected Cl
- Dilution V /V Volume V
Expected
...
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