1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58surface active agents in raw materials and formulated products Potentiometric two-phase titration m
2、ethodThe European Standard EN 14668:2005 has the status of a British StandardICS 71.100.40Surface active agents Determination of quaternary ammonium BRITISH STANDARDBS EN 14668:2005Incorporating Corrigendum No. 1BS EN 14668:2005This British Standard was published under the authority of the Standards
3、 Policy and Strategy Committee on 5 September 2005 BSI 2006ISBN 0 580 46388 5request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International
4、Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Stand
5、ard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 13 and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments iss
6、ued since publicationAmd. No. Date Comments16477 Corrigendum No. 130 June 2006 Correction to 4.8A list of organizations represented on this committee can be obtained on present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep
7、the UK interests informed; monitor related international and European developments and promulgate them in the UK.National forewordThis British Standard is the official English language version of EN 14668:2005, including Corrigendum May 2006.The UK participation in its preparation was entrusted to T
8、echnical Committee CII/34, Methods of test for surface active agents, which has the responsibility to: aid enquirers to understand the text;EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 14668June 2005ICS 71.100.40 Incorporating Corrigendum May 2006English versionSurface active agents - Determina
9、tion of quaternary ammoniumsurface active agents in raw materials and formulated products -Potentiometric two-phase titration methodAgents de surface - Dtermination des agents de surface base dammonium quaternaire dans les matires premireset les produits formuls - Mthode de titragepotentiomtrique da
10、ns deux phasesGrenzflchenaktive Stoffe - Bestimmung des Gehaltes anquartren Ammoniumtensiden in Rohstoffen undformulierten Produkten - Potentiometrische Zweiphasen-TitrationThis European Standard was approved by CEN on 19 May 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulat
11、ions 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 Central Secretariat or to any CEN member.This Europea
12、n 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 Central Secretariat has the same status as the officialversions.CEN members are the national s
13、tandards 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 COM
14、MITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14668:2005: EEN 14668:2005 (E) 2 Conten
15、ts Page Foreword 3 1 Scope .4 2 Normative references .4 3 Principle.4 4 Reagents4 5 Apparatus 5 6 Sampling and preparation of the test solution .6 7 Procedure 6 8 Calculation and expression of results.7 9 Precision8 10 Test report .8 Annex A (informative) Titration apparatus settings.9 Annex B (info
16、rmative) Potentiometric two-phase titration- typical titration curve11 Annex C (informative) Results of inter-laboratory test12 Bibliography.13 EN 14668:2005 (E) 3 Foreword This European Standard (EN 14668:2005) has been prepared by Technical Committee CEN/TC 276 “Surface active agents”, the secreta
17、riat 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 th
18、e 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, Luxemb
19、ourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14668:2005 (E) 4 1 Scope This European Standard specifies a method for the determination of the content of quaternary ammonium surface active agents in raw materials and formulat
20、ed 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
21、 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 Normat
22、ive 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 -
23、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 surf
24、ace 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 solut
25、ion 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
26、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 Yo
27、ur 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 a
28、s 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, C12H25OSO3Na, % (m/m)(C12H25O
29、SO3Na) 99 as determined following the method EN 14670. EN 14668:2005 (E) 5 4.3 Anionic surface active, agent standard volumetric solution, ca(C12H25OSO3Na) = 0,005 mol/l: 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
30、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, ca, expressed in millimoles per millilitre is calculated in accordance with the f
31、ollowing equation (1): 100a=Mwmc (1) 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(KC
32、l) = 3 mol/l 4.5 Hydrochloric acid, c(HCl)=0,5 mol/l. 4.6 Emulsifier, (TEGO Add1)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,
33、 denatured 96 % (V/V) 4.8 Methyl isobutyl 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 fo
34、llowing: 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. He
35、nce, 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 sui
36、table. 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,
37、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. EN 14668:2005 (E) 6 5.3 Combined glass pH-electrode. 5.4 Solvent
38、-resistant surface-active agent sensitive electrode (Surfactrode Refill or Surfactrode Resistant)2). 5.5 Ag/AgCl double-junction ground joint diaphragm reference electrode, inner and outer chambers filled with potassium chloride solution (4.4). 6 Sampling and preparation of the test solution 6.1 Sam
39、pling 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 s
40、ample 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 ma
41、rk 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
42、. 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 th
43、e 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 l 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
44、 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
45、 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. EN 14668:2005 (E) 7 The quaterna
46、ry ammonium surface active agent concentration is calculated according to Clause 8. 7.2 Determination of quaternary ammonium surface active agents in water soluble products Accurately transfer 10 ml of test solution (6.2.2) into the titration vessel and add 60 ml water. Adjust the pH to 3 0,2 with t
47、he hydrochloric acid solution (4.5). Add 30 ml of MIBK/ ethanol mixture (4.9) and 200 l 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 stir
48、ring (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. The quaternary ammonium surface active agent concentration is calculated according to Clause 8. 7.3 Cleaning, rinsing and condit
49、ioning of the measuring apparatus Rinse the measuring apparatus with ethanol (4.7) after each titration. Condition it by stirring for 20 s in the titration beaker filled with ethanol (4.7). NOTE For the surfactrode resistant, it is recommended to carry out three or four titrations before taking into account the results. 8 Calculation and expression of results The concentration of quaternary ammonium surface active agent (cc), expressed in millimoles per 100 g is calculated according to the following e
