EN 13267:2001

Surface active agents - Determination of water content - Karl Fischer method

This European Standard specifies the Karl Fischer method using electrometric end point detection for the determination of the water content of surface active agents. The method is applicable to products in form of powders, pastes and solutions.

Grenzflächenaktive Stoffe - Bestimmung des Wassergehaltes - Verfahren nach Karl Fischer

1 Anwendungsbereich
Diese Europäische Norm legt das Verfahren nach Karl Fischer, bei dem der elektrometrische Endpunktnachweis
angewendet wird, zur Bestimmung des Wassergehaltes von grenzflächenaktiven Stoffen fest.
Das Verfahren ist anwendbar für Produkte in Form von Pulvern, Pasten und Lösungen.
Die folgenden Substanzen reagieren mit dem Karl-Fischer-Reagenz: Alkalimetall von Silicaten, Carbonaten,
Hydroxiden und Boraten; Oxidationsmittel, Ketone, Aldehyde, starke mineralische Säuren und starke Basen.
Proben, die eine dieser Substanzen enthalten, können nicht direkt mit diesem Verfahren gemessen werden; in
solchen Fällen muss das Lösemittel-System und/oder das Karl-Fischer-Reagenz angepasst werden, diese
Anpassung liegt jedoch außerhalb des Anwendungsbereiches dieser Europäischen Norm.

Agents de surface - Détermination de la teneur en eau - Méthode de Karl Fischer

1 Domaine d'application
La présente norme européenne spécifie la méthode de Karl Fischer utilisant la détection électrométrique du point final de titrage pour la détermination de la teneur en eau des agents de surface.
La méthode est applicable aux produits sous forme de poudres, de pâtes et de solutions.
Les substances suivantes sont à l'origine d'interférences avec le réactif de Karl Fischer : silicates, carbonates, hydroxydes et borates de métaux alcalins ; agents oxydants, cétones, aldéhydes ; acides minéraux forts et bases fortes. Les échantillons contenant l'une de ces substances ne peuvent pas être directement soumis à l'analyse selon la présente méthode : le solvant et/ou le réactif de Karl Fischer doivent alors être transformés, mais ces modifications sont exclues du domaine d'application de la présente norme européenne.

Povšinsko aktivne snovi - Določevanje vode - Karl Fischerjeva metoda

General Information

• Status: Published
• Publication Date: 20-Mar-2001
• ICS: 71.100.40 - Surface active agents
• Technical Committee: CEN/TC 276 - Surface active agents
• Drafting Committee: CEN/TC 276/WG 1 - Methods of analysis
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 31-Oct-2024
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 13267:2002 - Surface active agents - Determination of water content - Karl Fischer method

Overview

EN 13267:2001 - Surface active agents: Determination of water content - Karl Fischer method (CEN) specifies a standardized Karl Fischer titration procedure using electrometric end‑point detection for measuring the water content of surface active agents. The method is applicable to surfactants supplied as powders, pastes and solutions and is intended for routine laboratory quality control and compositional analysis.

Key topics and technical requirements

• Scope and applicability: Designed for surface active agents in powder, paste or solution form. Samples containing certain interfering substances (alkali metal silicates, carbonates; hydroxides and borates; oxidizing agents; ketones and aldehydes; strong mineral acids or bases) cannot be measured directly without modifying the solvent system or reagent (such modifications are out of scope).
• Detection principle: Karl Fischer titration where water reacts with iodine/sulfur dioxide/amine in an appropriate solvent; end point detected electrometrically with a double platinum electrode.
• Reagents: Use analytical-grade reagents and Grade 1 water (EN ISO 3696). Preferred commercial Karl Fischer reagents (non‑pyridine formulations are recommended for safety); reagent water equivalent typically around 5 mg/ml (annex A describes pyridine-containing reagent preparation and target water equivalent range).
• Apparatus: Karl Fischer titrator (automatic or semi-automatic) with double platinum electrode, piston burette (resolution ≤ 0.01 ml), drying tubes (molecular sieve recommended), magnetic stirrer, gas‑tight syringes and analytical balance (0.1 mg accuracy).
• Methods: Two procedural routes - General method for homogeneous, easily dosed samples; Dissolution method for samples requiring dissolution before titration. Routine determination of reagent water equivalent is required (on new reagent containers and periodically).
• Precision: Repeatability and reproducibility limits are provided from interlaboratory tests (examples: for ~0.07% water r ≤ 0.005 g/100 g, R ≤ 0.02 g/100 g; for ~12.2% water r ≤ 0.3 g/100 g, R ≤ 0.6 g/100 g).

Applications and intended users

• Who uses it: QC laboratories, manufacturers of surfactants and detergents, analytical chemists, product formulators, and conformity assessment bodies.
• Practical uses: Incoming raw material inspection, batch release testing, stability studies, formulation control (water affects performance, shelf life and dosing), and troubleshooting production processes where water content influences product properties.

Related standards

• EN ISO 3696 - Water for analytical laboratory use (grade 1)
• ISO 607 - Sample division for surface active agents and detergents
• ISO 5725-2 - Accuracy (trueness and precision) of measurement methods (used for interlaboratory statistics)

Keywords: EN 13267:2001, Karl Fischer method, water content determination, surface active agents, electrometric end point, surfactant quality control.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.RGDGrenzflächenaktive Stoffe - Bestimmung des Wassergehaltes - Verfahren nach Karl FischerAgents de surface - Détermination de la teneur en eau - Méthode de Karl FischerSurface active agents - Determination of water content - Karl Fischer method71.100.40Površinsko aktivna sredstvaSurface active agentsICS:Ta slovenski standard je istoveten z:EN 13267:2001SIST EN 13267:2002en01-januar-2002SIST EN 13267:2002SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13267March 2001ICS 71.100.40English versionSurface active agents - Determination of water content - KarlFischer methodAgents de surface - Détermination de la teneur en eau -Méthode de Karl FischerGrenzflächenaktive Stoffe - Bestimmung desWassergehaltes - Verfahren nach Karl FischerThis European Standard was approved by CEN on 4 February 2001.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2001 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13267:2001 ESIST EN 13267:2002

Page 2EN 13267:2001ContentsForeword.31Scope.42Normatives references.43Term and definition.44Principle.45Reagents.46Apparatus.57Sampling.58Procedure.59Precision.810Test report.8Annex A
(informative)
Preparation of Karl Fischer reagent containing pyridine.9Annex B
(informative)
Interlaboratory test results.10Bibliography.11SIST EN 13267:2002

Page 3EN 13267:2001ForewordThis European Standard has been prepared by Technical Committee CEN/TC 276 "Surface active agents", thesecretariat 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 orby endorsement, at the latest by September 2001, and conflicting national standards shall be withdrawn at thelatest by September 2001.The annexes A and B are informative.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden,Switzerland and the United Kingdom.SIST EN 13267:2002

Page 4EN 13267:20011 ScopeThis European Standard specifies the Karl Fischer method using electrometric end point detection for thedetermination of the water content of surface active agents.The method is applicable to products in form of powders, pastes and solutions.The following substances interfere with Karl Fischer reagent : alkali metal silicates, carbonates ; hydroxydes andborates ; oxidizing agents, ketones, aldehydes ; strong mineral acids and strong bases. Samples that contain anyof these substances cannot be measured directly by this present method ; in those situation the solvent systemand/or the Karl Fischer reagent have to be modified, but these modifications are out of the scope of this EuropeanStandard.2 Normatives referencesThis European standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).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 Term and definitionFor the purposes of this European Standard, the following term and definition apply.3.1water contentamount of water, water of cristallization, absorbed water or occluded water, expressed as a percent by mass4 PrincipleThe water present in the test portion is reacted with a solution of iodine and sulfur dioxide in an appropriate mixture(Karl Fischer reagent), previously standardized by titration with an exactly known mass of water. The water contentis calculated from the amount of reagent used as percent by mass.5 ReagentsDuring the analysis, use only reagents of recognized analytical grade and water complying with grade 1 as definedin EN ISO 3696.5.1Solvent, methanol, 2-methoxyethanol or propan-1-olNOTEThe water content should be as low as possible in order to save Karl Fischer reagent.5.2Karl Fischer reagent, having a water equivalent of approximately 5 mg/ml, preferably commerciallyprepared.NOTEA non-pyridine containing reagent is preferred mainly for safety reasons. A commercially available reagentcontaining iodine, sulfur dioxide and an amine dissolved in 2-methoxyethanol is suitable. A pyridine reagent can be used if it hasbeen shown to be suitable. This should be included in the test report. A reagent containing pyridine can be prepared asspecified in annex A.SIST EN 13267:2002

Page 5EN 13267:20016 ApparatusOrdinary laboratory apparatus and the following:6.1Karl Fischer apparatus, fully automatic or semi-automatic, consisting of: titrator with double platinum electrode; piston burette, with a resolution less or equal to 0,01 ml; capable of controlling the dosage rate, the time ofdelay, the stop time and the drift; drying tubes containing molecular sieve pore size 0,3 nm (silica gel is not sufficient as a protective agent); magnetic stirrer.6.2Gas tight syringe, capacity 100 µl (optional).6.3Clinical glass syringe, with movable needle.6.4Analytical balance, accurate to 0,1 mg.7 SamplingThe laboratory sample shall have been prepared and stored in accordance with ISO 607.8 Procedure8.1 GeneralAtmospheric moisture is the biggest source of interference in the Karl Fischer titration. Take care to dry theapparatus thoroughly and to handle the test portions and solvents speedly to prevent access of moisture. Operatethe Karl Fischer apparatus, in accordance with the manufacturer's instructions.8.2 Determination of the water equivalent of the Karl Fischer reagent8.2.1 GeneralDetermine the water equivalent on each new container of reagent and then at least weekly.NOTEThe water equivalent can change during storage. The type of apparatus used and the desired analytical accuracygovern the frequency of determination of the water equivalent.8.2.2 PreparationClean the electrode with tissue paper moistened with a suitable solvent, e.g. acetone. Wipe-off the acetone. Installa clean and dry titration vessel ; introduce a clean and dry magnetic stirring bar.Transfer enough volume of solvent (5.1) as to immerse the electrode platinum tips by 2 mm to 3 mm.Titrate with the Karl Fischer reagent (5.2) in order to neutralize any trace of moisture, avoiding any excess ofreagent.NOTEIf an automatic apparatus is used, the following instrumental conditions are recommended: maximum dosage rate15 ml/min; minimum increment9 µl;SIST EN 13267:2002

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