Surface active agents - Determination of anionic surface active agents and soaps in detergents and cleansers - Potentiometric two-phase titration method

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.

Grenzflächenaktive Stoffe - Bestimmung des Gehaltes an anionischen grenzflächenaktiven Stoffen und Seifen in Detergenzien und Reinigern - Potentiometrische Zweiphasen-Titration

Diese Europäische Norm legt ein Verfahren zur Bestimmung des Gehaltes an anionischen grenzflächen-aktiven
Stoffen und Seifen in Detergenzien und Reinigern als Menge an anionischen grenzflächenaktiven
Stoffen fest, angegeben in Millimol je 100 g Produkt.
ANMERKUNG 1 Die Anwendbarkeit auf andere Produkte als die geprüften sollte in jedem einzelnen Fall geprüft
werden.
ANMERKUNG 2 Im Vergleich zur üblichen Zweiphasen-Titration mit visueller Endpunktbestimmung (siehe ISO 2271)
bietet die potentiometrische Titration den Vorteil der Automatisierung, vom Analytiker abhängige Abweichungen bei der
Erkennung des Äquivalenzpunktes können vernachlässigt werden und ein nicht kritisches Lösemittel ersetzt das
toxikologisch kritische Chlorofom.

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

La présente Norme européenne spécifie une méthode de détermination de la teneur en agents de surface anioniques et en savons dans les détergents et les produits nettoyants, cette teneur étant définie comme la quantité d'agents de surface anioniques exprimée en millimoles par 100 g de produit.
NOTE 1   Il convient de vérifier, dans chaque cas particulier, l'application possible de cette méthode à des produits différents des produits soumis à l'essai.
NOTE 2   Comparé au titrage dans deux phases à détermination visuelle du point final utilisé couramment en laboratoire (voir l'ISO 2271), le titrage potentiométrique offre l'avantage que le procédé est automatisé, que la détection du point d'équivalence ne dépend pas de l'opérateur et qu'un solvant "non critique" remplace le chloroforme qui présente des risques toxicologiques.

Površinsko aktivne snovi – Določevanje anionskih površinsko aktivnih snovi in mil v detergentih in čistilih – Metoda potenciometrijske dvofazne titracije

General Information

Status
Published
Publication Date
21-Jun-2005
Current Stage
9060 - Closure of 2 Year Review Enquiry - Review Enquiry
Due Date
03-Jun-2020
Completion Date
03-Jun-2020

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SLOVENSKI STANDARD
SIST EN 14669:2005
01-november-2005

3RYUãLQVNRDNWLYQHVQRYL±'RORþHYDQMHDQLRQVNLKSRYUãLQVNRDNWLYQLKVQRYLLQPLO

YGHWHUJHQWLKLQþLVWLOLK±0HWRGDSRWHQFLRPHWULMVNHGYRID]QHWLWUDFLMH

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
SIST EN 14669:2005 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 14669:2005
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SIST EN 14669:2005
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.
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SIST EN 14669:2005
EN 14669:2005 (E)
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

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SIST EN 14669:2005
EN 14669:2005 (E)
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.

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SIST EN 14669:2005
EN 14669:2005 (E)
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.
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SIST EN 14669:2005
EN 14669:2005 (E)

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

millilitre is calculated in accordance with the following equation (1):
m × w
c = (1)
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).
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.
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SIST EN 14669:2005
EN 14669:2005 (E)
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

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 produ
...

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