EN 14669:2005

SLOVENSKI STANDARD
01-november-2005
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Surface active agents - Determination of anionic surface active agents and soaps in
detergents and cleansers - Potentiometric two-phase titration method
Grenzflächenaktive Stoffe - Bestimmung des Gehaltes an anionischen
grenzflächenaktiven Stoffen und Seifen in Detergenzien und Reinigern -
Potentiometrische Zweiphasen-Titration
Agents de surface - Détermination des agents de surface anioniques et des savons dans
les détergents et produits de nettoyants - Méthode de titrage potentiométrique dans deux
phases
Ta slovenski standard je istoveten z: EN 14669:2005
ICS:
71.100.40 Površinsko aktivna sredstva Surface active agents
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 14669
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2005
ICS 71.100.40
English version
Surface active agents - Determination of anionic surface active
agents and soaps in detergents and cleansers - Potentiometric
two-phase titration method
Agents de surface - Détermination des agents de surface Grenzflächenaktive Stoffe - Bestimmung des Gehaltes an
anioniques et des savons dans les détergents et produits anionischen grenzflächenaktiven Stoffen und Seifen in
de nettoyants - Méthode de titrage potentiométrique dans Detergenzien und Reinigern - Potentiometrische
deux phases Zweiphasen-Titration
This European Standard was approved by CEN on 19 May 2005.
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. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14669:2005: E
worldwide for CEN national Members.

Contents
Page
Foreword .3
1 Scope.4
2 Normative references.4
3 Principle.4
4 Reagents.4
5 Apparatus.6
6 Sampling and preparation of the test solution .7
7 Procedure.7
8 Calculation and expression of results.9
9 Precision.9
10 Test report.10
Annex A (informative) Titration apparatus settings.11
Annex B (informative) Potentiometric two-phase titration- typical titration curve.13
Annex C (informative) Results of inter-laboratory test.14
Bibliography.16

Foreword
This European Standard (EN 14669:2005) has been prepared by Technical Committee CEN/TC 276 “Surface
active agents”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical text or
by endorsement, at the latest by December 2005, and conflicting national standards shall be withdrawn at the latest
by December 2005.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
1 Scope
This European Standard specifies a method for the determination of the content of anionic surface active agents
and soaps in detergents and cleansers, defined as being the amount of anionic surface active agents expressed in
millimoles per 100 g of product.
NOTE 1 The applicability in products different that those tested should be checked in each particular case.
NOTE 2 In comparison to usual laboratory two-phase titration with visual endpoint determination (see ISO 2271),
potentiometric titration offers the advantage of automation; operator-dependent differences in recognising the equivalence point
can be neglected, and a non-critical solvent replaces the toxicologically critical chloroform.
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.
EN 14670, Surface active agents – Sodium dodecyl sulfate – Analytical method.
EN ISO 3696, Water for analytical laboratory use – Specification and test methods (ISO 3696:1987).
ISO 607, Surface active agents and detergents – Methods of sample division.
3 Principle
Anionic surface active agents and soaps are combined with cationic surface active agents to form water-insoluble
ion pairs which are immediately extracted into a water immiscible organic solvent. This fundamental reaction is the
basis for the titration of equivalents of ionic surface active agents with an oppositely charged surface active agent
standard volumetric solution in the two-phase titration.
This procedure is supported by intensively stirring the two-phase mixture of aqueous solution and organic phase.
The potential, which is formed in the emulsion during the titration, is recorded with the help of a special solvent-
resistant surface active agent-sensitive electrode in combination with a silver/silver chloride reference electrode
against the amount of titrant added. The equivalence point of the added cationic surface active agent corresponds
to that one of the test solution at the inflection point of the titration curve (Annex B).
The titration is carried out twice, once under acidic conditions for the determination of the anionic surface active
agents and then under alkaline conditions in order to determine the sum of soaps and anionic surface active
agents. The soap concentration is calculated from the difference of the titrant consumptions.
4 Reagents
WARNING — Your attention is drawn to the regulations covering the handling of hazardous substances.
Technical, organisational and personal protection measures should be observed.
During the analysis, unless otherwise specified, use only reagents of recognised analytical grade that have been
checked in advance as to not interfere with the analytical results.
4.1 Water, complying with grade 3 as defined in EN ISO 3696.
NOTE If the water is purified via ion-exchange resins, ensure that no cationic or anionic species from the resins
cause interference.
4.2 Sodium dodecyl sulfate, C H OSO Na, % (m/m)(C H SO Na) ≥ 99 as determined following the
12 25 3 12 25 4
method EN 14670.
4.3 Anionic surface active agent standard volumetric solution, c (C H OSO Na )= 0,005 mol/l.
12 25 3
Weigh 1,455 g of sodium dodecyl sulfate (4.2) with a known active content to the nearest 1 mg, in a conical flask,
and dissolve in about 500 ml water. Transfer quantitatively the solution into a 1000 ml volumetric flask and make up
to the mark with water and mix well.
The concentration of the anionic surface active agent standard volumetric solution, c , expressed in millimoles per
a
millilitre is calculated in accordance with the following equation (1):
m × w
c =  (1)
a
M × 100
where
m is the mass of sodium dodecyl sulfate (4.2) in grams;
w is the active matter content of sodium dodecyl sulfate (4.2) in grams per 100 g;
M is the molar mass of sodium dodecyl sulfate , in grams per mole (288,4 g/mol).
1)
4.4 1,3-didecyl-2-methyl-imidazolium chloride (e.g. TEGO Trant A100 ).
4.5 Cationic surface active agent, standard volumetric solution, c = 0,005 mol/l:
Weigh 2,00 g of 1,3-didecyl-2-methyl-imidazolium chloride (4.4), to the nearest 1 mg, in a conical flask and dissolve
it in about 500 ml water. Transfer quantitatively the solution into a 1000 ml volumetric flask, make up to the mark
with water and mix well. Standardize the solution as specified in 7.1.
Standardize the cationic surface active agent solution only when the solution has reached its equilibrium, i.e. after
standing for at least one day.
NOTE Cationic surface active agents adsorb on glass surfaces like such of the burette and reagent bottle of the titration
unit.
4.6 Potassium chloride solution, c(KCl) = 3 mol/l.
4.7 Hydrochloric acid, c(HCl)=0,5 mol/l.
4.8 Sodium hydroxide solution, c(NaOH)=0,5 mol/l.

1) TEGO Trant A100 is the trade name of product supplied by Metrohm Ltd. (CH-9101 Herisau, Switzerland). This information
is given for the convenience of users of this document and does not constitute an endorsement by CEN of this product.
Equivalent product may be used if it can be shown to lead to the same results.
2)
4.9 Emulsifier (TEGO Add ).
NOTE The emulsifier has the task of supporting the formation of a stable emulsion and at the same time of preventing the
deposition of the ion associate formed during the titration on the electrode surface.
4.10 Propan-2-ol (Isopropanol) (C H 0) ≥ 99 %.
3 8
4.11 Ethanol denatured 96% (V/V).
4.12 Methyl isobutyl ketone (MIBK) (CAS number: 108.10.1), 4-methyl-2-pentanone, % (m/m) (C H O) ≥ 99.
6 12
4.13 MIBK / propan-2-ol - mixture
Measure 600 ml MIBK (4.12) and 400 ml propan-2-ol (4.10) using a measuring cylinder, transfer into a 1000 ml
flask and mix well.
5 Apparatus
Normal laboratory apparatus and the following:
5.1 Automatic potentiometric titration apparatus, with drift-controlled data acquisition and dynamic titrimetric
dosing equipped with a piston burette delivery system of 20 ml capacity.
5.2 Propeller stirring system.
In a potentiometric two-phase titration a thorough blending is required. Hence, a stirring propeller is compulsory.
The stirrer should be constructed so that an optimal emulsification of the vessel contents is achieved with a
simultaneous low degree of air entrapment. Propeller stirrers shaped like ship screws have proven effective, while
magnetic stirrers are not suitable. It is advisable to pay special attention to the geometric arrangement of the
immersing parts (electrodes, burette tip, and stirrer). If arranged optimally, no foam is produced, not even with
heavy stirring.
5.3 Combined glass pH-electrode.
5.4 Solvent-resistant- surface active agent -sensitive electrode (Surfactrode Refill or Surfactrode
3)
Resistant) .
5.5 Ag/AgCl- double-junction ground joint diaphragm reference electrode, inner and outer chambers filled
with potassium chloride solution (4.6).

2) TEGO Add is the trade name of product supplied by Metrohom Ltd. (CH-9101 Herisau, Switzerland). This information
is given for the convenience of users of this document and does not constitute an endorsement by CEN of this product.
Equivalent product may be used if it can be shown to lead to the same results.
3) Surfactrode Refill and Surfactrode Resistant are trade names of products supplied by Metrohm Ltd. (CH-9101 Herisau,
Switzerland). This information is given for the convenience of users of this document and does not constitute an endorsement
by CEN. Equivalent products may be used if they can be shown to lead to the same results.
6 Sampling and preparation of the test solution
6.1 Sampling
The sample shall be taken and stored in accordance with ISO 607.
6.2 Preparation of the test solution
Powder detergents and powdery cleansers shall be homogenised by additional milling if amounts l
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