EN 14668:2005
(Main)Surface active agents - Determination of quaternary ammonium surface active agents in raw materials and formulated products - Potentiometric two-phase titration method
Surface active agents - Determination of quaternary ammonium surface active agents in raw materials and formulated products - Potentiometric two-phase titration method
This European Standard specifies a method for the determination of the content of quaternary ammonium surface active agents in raw materials and formulated products, defined as being the amount of quaternary ammonium surface active agents expressed in millimoles per 100 g of product.
NOTE 1 The applicability in products different than 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 2871-1 and ISO 2871-2) 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 quartären Ammoniumtensiden in Rohstoffen und formulierten Produkten - Potentiometrische Zweiphasen-Titration
Diese Europäische Norm legt ein Verfahren zur Bestimmung des Gehaltes an quartären Ammoniumtensiden
in Rohstoffen und formulierten Produkten als Menge an quartären Ammoniumtensiden 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 2871-1
und ISO 2871-2) 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 ammonium quaternaire dans les matières premières et les produits formulés - Méthode de titrage potentiométrique dans deux phases
La présente Norme européenne spécifie une méthode de détermination de la teneur en agents de surface ammonium quaternaire dans les matières premières et les produits formulés, cette teneur se définissant comme la quantité d'agents de surface ammonium quaternaire exprimée en millimoles pour 100 g de produit.
NOTE 1 Il convient de vérifier, pour 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 2871-1 et l'ISO 2871-2), le titrage potentiométrique offre l'avantage que le procédé est automatisé, que les écarts imputables à l'opérateur dans la détection du point d'équivalence peuvent être négligés et qu'un solvant non critique remplace le chloroforme qui présente des risques toxicologiques.
Površinsko aktivne snovi – Določevanje kvarternih amonijevih površinsko aktivnih snovi v surovinah in gotovih formulacijah – Metoda potenciometrijske dvofazne titracije
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2005
3RYUãLQVNRDNWLYQHVQRYL±'RORþHYDQMHNYDUWHUQLKDPRQLMHYLKSRYUãLQVNRDNWLYQLK
VQRYLYVXURYLQDKLQJRWRYLKIRUPXODFLMDK±0HWRGDSRWHQFLRPHWULMVNHGYRID]QH
WLWUDFLMH
Surface active agents - Determination of quaternary ammonium surface active agents in
raw materials and formulated products - Potentiometric two-phase titration method
Grenzflächenaktive Stoffe - Bestimmung des Gehaltes an quartären Ammoniumtensiden
in Rohstoffen und formulierten Produkten - Potentiometrische Zweiphasen-Titration
Agents de surface - Détermination des agents de surface ammonium quaternaire dans
les matieres premieres et les produits formulés - Méthode de titrage potentiométrique
dans deux phases
Ta slovenski standard je istoveten z: EN 14668:2005
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 14668
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2005
ICS 71.100.40
English version
Surface active agents - Determination of quaternary ammonium
surface active agents in raw materials and formulated products -
Potentiometric two-phase titration method
Agents de surface - Détermination des agents de surface à Grenzflächenaktive Stoffe - Bestimmung des Gehaltes an
base d'ammonium quaternaire dans les matières premières quartären Ammoniumtensiden in Rohstoffen und
et les produits formulés - Méthode de titrage formulierten Produkten - Potentiometrische Zweiphasen-
potentiométrique dans deux phases 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 14668:2005: 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 .5
6 Sampling and preparation of the test solution .6
7 Procedure .6
8 Calculation and expression of results.7
9 Precision.8
10 Test report .8
Annex A (informative) Titration apparatus settings.9
Annex B (informative) Potentiometric two-phase titration- typical titration curve.11
Annex C (informative) Results of inter-laboratory test.12
Bibliography.13
Foreword
This European Standard (EN 14668:2005) 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 quaternary ammonium surface
active agents in raw materials and formulated products, defined as being the amount of quaternary ammonium
surface active agents expressed in millimoles per 100 g of product.
NOTE 1 The applicability in products different than 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 2871-1 and
ISO 2871-2) 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
Quaternary ammonium surface active agents are combined with anionic surface active agent 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 process 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 anionic surface active agent corresponds to that one
of the test solution at the inflection point of the titration curve (Annex B).
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 recognized 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 OSO Na) ≥ 99 as determined following the
12 25 3 12 25 3
method EN 14670.
4.3 Anionic surface active, agent standard volumetric solution, c (C H OSO Na) = 0,005 mol/l:
a 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, 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).
4.4 Potassium chloride, solution, c(KCl) = 3 mol/l
4.5 Hydrochloric acid, c(HCl)=0,5 mol/l.
1)
4.6 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.
4.7 Ethanol, denatured 96 % (V/V)
4.8 Methyl iso-butyl ketone (MIBK) (CAS number: 108.10.1), 4-methyl-2-pentanone
4.9 MIBK/ethanol-mixture
Measure 500 ml MIBK (4.8) and 500 ml ethanol (4.7) 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 been 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.
1) TEGO Add is the trade name of a 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 the product named.
Equivalent products may be used if they can be shown to lead to the same results.
5.3 Combined glass pH-electrode.
2)
5.4 Solvent-resistant surface-active agent sensitive electrode (Surfactrode Refill or Surfactrode Resistant) .
. , inner and outer chambers filled
5 5 Ag/AgCl – double-junction ground joint diaphragm reference electrode
with potassium chloride solution (4.4).
6 Sampling and preparation of the test solution
6.1 Sampling
The sample shall be taken and stored in accordance with ISO 607.
Solid samples shall be carefully melted in an oven at 60 °C taking care that they are firmly tight in order to avoid
loosing volatile matter.
6.2 Preparation of the test solution
6.2.1 Raw materials (organic solvent soluble)
The sample amount and the concentration of test solution shall be calculated in a way that the consumption of the
titrant solution (4.3) used for the titration of 10 ml test solution is approximately 10 ml.
Weigh to the nearest 0,1 mg the homogenised sample in a 200 ml volumetric flask, make up to the mark with
MIBK/ethanol-mixture (4.9) and mix well.
6.2.2 Formulated products (water soluble)
The sample amount and the concentration of the test solution shall be calculated in a way that the consumption of
the titrant solution (4.3) used for the titration of 10 ml test solution is approximately 10 ml.
Weigh to the nearest 0,1 mg of the homogenised sample in a 200 ml volumetric flask, make up to the mark with
water and mix well.
7 Procedure
7.1 Determination of quaternary ammonium surface active agents in organic solvent soluble
products
Accurately transfer 10 ml of test solution (6.2.1) into the titration vessel and add about 70 ml water.
Adjust the pH to 3 ± 0,2 with the acid solution (4.5).
Add 20 ml of MIBK/ ethanol mixture (4.9) and 200 µl of emulsifier (4.6). Stir the mixture intensively for 60 s in order
to form a stable emulsion.
Carry out the titration with the anionic surface-active agent standard volumetric solution (4.3) under intensive
stirring (5.2).
Record the reagent consumption, V, at the inflection point of the titration curve (see Figure B.1).
NOTE Examples for instrument settings are given in Annex A.
2) 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.
...
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