1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58agents and soaps in detergents and cleansers Potentiometric two-phase titration methodThe European
2、Standard EN 14669:2005 has the status of a British StandardICS 71.100.40Surface active agents Determination of anionic surface active BRITISH STANDARDBS EN 14669:2005BS EN 14669:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 5 September
3、2005 BSI 5 September 2005ISBN 0 580 46387 7request 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 Standards Correspondence Index”, o
4、r 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 Standard does not of itself confer immu
5、nity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 16, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since pu
6、blicationAmd. No. Date CommentsA 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 UK interests informed; monitor related international and European
7、 developments and promulgate them in the UK.National forewordThis British Standard is the official English language version of EN 14669:2005.The UK participation in its preparation was entrusted to Technical Committee CII/34, Methods of test for surface active agents, which has the responsibility to
8、: aid enquirers to understand the text;EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 14669June 2005ICS 71.100.40English versionSurface active agents - Determination of anionic surface activeagents and soaps in detergents and cleansers - Potentiometrictwo-phase titration methodAgents de surface -
9、 Dtermination des agents de surfaceanioniques et des savons dans les dtergents et produitsde nettoyants - Mthode de titrage potentiomtrique dansdeux phasesGrenzflchenaktive Stoffe - Bestimmung des Gehaltes ananionischen grenzflchenaktiven Stoffen und Seifen inDetergenzien und Reinigern - Potentiomet
10、rischeZweiphasen-TitrationThis 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 EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and
11、 bibliographical references concerning such nationalstandards 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 translationunder the responsibility
12、 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 standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, L
13、atvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 C
14、EN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14669:2005: EEN 14669:2005 (E) 2 Contents Page Foreword 3 1 Scope .4 2 Normative references .4 3 Principle.4 4 Reagents4 5 Apparatus 6 6 Sampling and preparation of the test solution .7
15、7 Procedure 7 8 Calculation and expression of results.9 9 Precision9 10 Test report .10 Annex A (informative) Titration apparatus settings.11 Annex B (informative) Potentiometric two-phase titration- typical titration curve13 Annex C (informative) Results of inter-laboratory test14 Bibliography.16 E
16、N 14669:2005 (E) 3 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 te
17、xt 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
18、: 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. EN 14669:2005 (E) 4 1 Scop
19、e 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 dif
20、ferent 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 equivalen
21、ce 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
22、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 Metho
23、ds 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 equivalen
24、ts 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 d
25、uring 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
26、 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 s
27、urface 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. Duri
28、ng 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
29、that no cationic or anionic species from the resins cause interference. EN 14669:2005 (E) 5 4.2 Sodium dodecyl sulfate, C12H25OSO3Na, % (m/m)(C12H25SO4Na) 99 as determined following the method EN 14670. 4.3 Anionic surface active agent standard volumetric solution, c (C12H25OSO3Na )= 0,005 mol/l. We
30、igh 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
31、surface active agent standard volumetric solution, ca, expressed in millimoles per millilitre is calculated in accordance with the following equation (1): 100 a=Mw mc (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 g
32、rams 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 A1001). 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 c
33、hloride (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
34、 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
35、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
36、this product. Equivalent product may be used if it can be shown to lead to the same results. EN 14669:2005 (E) 6 4.9 Emulsifier (TEGO Add2). 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
37、 during the titration on the electrode surface. 4.10 Propan-2-ol (Isopropanol) (C3H80) 99 %. 4.11 Ethanol denatured 96% (V/V). 4.12 Methyl isobutyl ketone (MIBK) (CAS number: 108.10.1), 4-methyl-2-pentanone, % (m/m) (C6H12O) 99. 4.13 MIBK / propan-2-ol - mixture Measure 600 ml MIBK (4.12) and 400 ml
38、 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 burett
39、e 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 simult
40、aneous 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,
41、 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)3). 5.5 Ag/AgCl- double-junction ground joint diaphragm reference electrode, inner and outer chambers fil
42、led 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
43、 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
44、 by CEN. Equivalent products may be used if they can be shown to lead to the same results. EN 14669:2005 (E) 7 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 powd
45、ery cleansers shall be homogenised by additional milling if amounts lower than 10 g are used. The sample amount and the concentration of test solution shall be calculated in a way that the consumption of the titrant solution (4.5) used for the titration of 10 ml test solution is approximately 10 ml.
46、 Weigh, to the nearest 0,1 mg, the homogenised sample (m1) in a glass beaker and add approximately 100 ml water. Stir the mixture using a magnetic stirrer until the substance is dissolved and possibly insoluble product ingredients are suspended homogeneously in the solution. For soap raw material he
47、ating is necessary to achieve complete dissolution. For fatty acids instead of water, ethanol is used as solvent. Transfer quantitatively the sample solution into a 200 ml volumetric flask, to minimise foaming add a small quantity of ethanol (4.11). Make up to the mark with water and mix well. 7 Pro
48、cedure 7.1 Standardisation of the cationic surface active agent standard volumetric solution Accurately transfer 10 ml of the sodium dodecyl sulfate standard volumetric solution (4.3) into the titration vessel and add about 70 ml of water. Adjust the pH to 3 0,2 with the hydrochloric acid solution (
49、4.7). Add 10 ml of methyl isobutyl ketone (MIBK )(4.12), 10 ml of ethanol (4.11) and 200 l of emulsifier (4.9). Stir the mixture intensively for 60 s in order to form a stable emulsion. Carry out the titration with the cationic surface active agent standard volumetric solution (4.5) 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. EN 14669:2005 (E) 8 Calculate the fac
