1、Designation: D 6173 97 (Reapproved 2005)Standard Test Method forDetermination of Various Anionic Surfactant Actives byPotentiometric Titration1This standard is issued under the fixed designation D 6173; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is based on a potentiometric titration ofcommon anionic surfactants
3、and blends of anionic surfactantwith a hydrotrope. This test method solely is intended for theanalysis of active matter in the following surfactants: alcoholether sulfate, alpha olefin sulfonate, alkylbenzene sulfonicacid, alcohol sulfate, sodium alkylbenzene sulfonate/sodiumxylene sulfonate blend (
4、5:1), sodium alkylbenzene sulfonate/sodium xylene sulfonate blend (16:1), and sodium alkylben-zene sulfonate/sodium xylene sulfonate blend (22:1). It has notbeen tested for surfactant formulations.1.2 This standard does not purport to address all the safetyconcerns, if any, associated with its use.
5、It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use. Material Safety Data Sheets areavailable for reagents and materials. Review them for hazardsprior to usage.2. Referenced Doc
6、uments2.1 ASTM Standards:2D 459 Terminology Relating to Soaps and Other DetergentsD 1681 Test Method for Synthetic Anionic Active Ingredi-ent in Detergents by Cationic Titration ProcedureD 3049 Test Method for Synthetic Anionic Ingredient byCationic Titration3. Terminology3.1 Definitions of Terms Sp
7、ecific to This Standard:3.1.1 active matter, nthe organic surface-active materialpresent in the detergent. Also defined in Terminology D 459 asactive ingredient of detergents.4. Summary of Test Method4.1 This test method describes a potentiometric titrationprocedure for determining active matter in
8、anionic surfactant.The anionic surfactant is first dissolved in water, and the pH ofthe solution is adjusted according to the type of anionicsurfactant being measured. In the potentiometric titration theanionic surfactant is titrated with a standard solution ofHyamine using a surfactant electrode, a
9、nd the reaction involvesthe formation of a complex between the anionic surfactant andthe cationic titrant (Hyamine), which then precipitates. At theend point the surfactant electrode appears to respond to anexcess of titrant with potential change large enough to give awell defined inflection in the
10、titration curve.5. Significance and Use5.1 The most common anionic surfactants presented in thistest method are used widely in synthetic detergents and otherhousehold cleaners. Current analysis of the active matter inthese anionic surfactants involves the two-phase aqueous/chloroform titration with
11、a mixed indicator, organic dyes suchas disulphine blue/dimidium bromide (see Test MethodD 3049), and methylene blue (see Test Method D 1681). Thistest method eliminates the use of hazardous chloroform, theuse of which is restricted for environmental and toxicologicalreasons.5.2 This test method also
12、 describes the titration of variousratio blends of sodium alkylbenzene sulfonate and sodiumxylene sulfonate. Active matter content in these blends isattributable directly to sodium alkylbenzene sulfonate. There-fore, the presence of various amounts of sodium xylenesulfonate in these blends does not
13、interfere with the determi-nation of percent actives.6. Apparatus6.1 Autotitration System, equipped with a delivery buretsystem, 10 or 20-mL capacity.3,41This test method is under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergents and is the direct responsibility of Subcommittee D12
14、.12 onAnalysis and Specifications of Soaps, Synthetics, Detergents and their Components.Current edition approved May 1, 2005. Published June 2005. Originallyapproved in 1997. Last previous edition approved in 1997 as D 6173-97.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orc
15、ontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The sole source of supply of the autotitration system and Phoenix electrodeknown to the committee at this time is Brinkmann Instrumen
16、ts, Inc. Cantiague Rd.,Westbury, NY 11590.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Phoenix Surfactant Combination Electrode3,4, nitratespecific ion electrode, or surfactant electrode4,5equipped withsilver/silver chloride r
17、eference electrode.5The conditioning ofthis type of electrode is essential for obtaining a good break inthe titration curve. Therefore, each electrode should be condi-tioned in sodium lauryl sulfate 0.0001M solution for 15 min.For other electrode requirements, follow the manufacturersinstruction man
18、ual.6.3 Analytical Balance.6.4 Standard Laboratory Glassware.7. Reagents67.1 Hyamine 1622, diisobutylphenoxyethoxyethyl dimethylbenzyl ammonium chloride monohydrate.7.2 Potassium Chloride, reagent grade.7.3 Triton X-1004,7, electrophoresis grade.7.4 Potassium Chloride 4.0 M SolutionPrepare by weigh-
19、ing out 30.00 g to the nearest 0.01 g of potassium chloride intoa 100 mL volumetric glass and dissolving in deionized water.Dilute to the mark with deionized water.Add exactly one dropof Triton X-100 to the solution and mix well. This is only areference electrode filling solution for the Phoenix ele
20、ctrode.7.5 Triton X-100, 1 % SolutionPrepare by weighing 1.00g of Triton X-100 into a 100-mL volumetric flask and dilutingto the mark with deionized water.7.6 Sodium Lauryl Sulfate4,8, primary standard.NOTE 1Sodium lauryl sulfate shall be analyzed for purity accordingto the reagent section of Test M
21、ethod D 3049 before its use as primarystandard.7.7 Buffer Solution pH 4.004,97.8 Buffer Solution pH 7.004,9Pipet 10 mL of buffersolution pH 7.00 and transfer to a 100-mL volumetric flask.Dilute to volume and mix well.7.9 Sodium Lauryl Sulfate 0.0001 m Solution, buffered atpH 4.00, with a graduated c
22、ylinder transfer 2 mL of sodiumlauryl sulfate 0.004 M solution to a 150-mLbeaker.Add 80 mLof deionized water and 1 mL of buffer solution pH 4.00 andmix well. This solution is use for conditioning the electrodes.7.10 Electrode Rinse SolutionTransfer approximately 50mL of 0.1 M HCl solution to 1 L vol
23、umetric flask and dilute tovolume.8. Preparation of Primary Standard Reagents8.1 Sodium Lauryl Sulfate Solution,43 10-3N. Weighaccurately 1.15 + 0.01 g of sodium lauryl sulfate to the nearest0.1 mg. Dissolve in water and dilute to a final volume of 1L.Calculate the normality of the solution accordin
24、g to thefollowing equation:Normality of Sodium Lauryl Sulfate 5W 3 P288.383 100!(1)where:P = purity of the sodium lauryl sulfate, weight %, andW = weight of sodium lauryl sulfate, g.8.2 Keep the solution no longer than one month beforemaking a fresh solution.8.3 Hyamine 1622 Solution,43 10-3NDissolv
25、e 1.85 +0.5 g of Hyamine 1622 in deionized water and dilute to a finalvolume of 1 L.8.4 Hyamine 1622 Solution Standardization,43 10-3NThis determination shall be done in triplicate. Pipet 5.00mL of the standard lauryl sulfate solution into a 150-mLbeaker. Add 50 mL of dionized water, and, while stir
26、ring, add1 mL of buffer solution pH 4 and 1 mL of Triton-X-100, 1 %solution. To minimize noise in the titration, make sure that theburet tip is placed close to the center of the stir bar. Stirmoderately. Erroneous results can occur if excessive foamingtakes place. Titrate potentiometrically with the
27、 Hyamine 1622solution and record the titration volume. The Titroprocessorwill perform the titration, determine the inflection point andcalculate the results according to the following equation:Normality of Hyamine 1622 5N 3 5V(2)where:N = normality of sodium lauryl sulfate standard solution,5 = sodi
28、um lauryl sulfate aliquot taken for titration, mL,andV = Hyamine 1622 solution required to reach the endpoint,mL.8.5 The electrode should be cleaned between each titration.A satisfactory procedure is to first rinse with the acid rinsesolution and then with deionized water. Blot dry with a soft,lint-
29、free tissue. For other electrodes follow the manufacturersinstructions.9. Hazards9.1 All reagents and chemicals shall be handled with care.Before using any chemical, read and follow all safety instruc-tions on the manufacturers label or MSDS (Material SafetyData Sheet).10. Procedure for Determinatio
30、n of Actives in AnionicSurfactants10.1 Weigh a quantity of sample to the nearest 0.1 mg thatcontains approximately 0.016 meq/4.0 mL anionic surfactantactive material into a 1-L volumetric glass (see Note 2). Diluteto volume with deionized water. Mix well, and pipet thecorresponding aliquot. For the
31、alcohol ether sulfate, or alphaolefin sulfonate sample, or both, add to the correspondingaliquot 70 mL of deionized water 1 mL of buffer solution pH4If you are aware of alternative suppliers, please provide this information toASTM headquarters. Your comments will receive careful consideration at a m
32、eetingof the responsible technical committee, which you may attend.5The sole source of supply of the electrodes known to the committee at this timeis Orion Research, Inc., 529 Main St., Boston, MA 02129.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washingto
33、n, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia andNational Formulary, U.S. Pharmacopeial Convention, Inc., (USPC), Rockville, MD.7The sole so
34、urce of supply of Triton-X-100 known to the committee at this timeis Fisher Scientific, 711 Forbes Ave., Pittsburgh, PA 15219-4785.8The sole source of supply of sodium lauryl sulfate known to the committee atthis time is Gallard Schlesinger Chemical Manufacturing Corp., 584 Mineola Ave.,Carle Place,
35、 NY 11514.9The sole source of supply of buffer solution known to the committee at this timeis Fisher Scientific, 711 Forbes Ave., Pittsburgh, PA 15219-4785.D 6173 97 (2005)27.00 and 1 mL of 1 % Triton-X-100 solution. Proceed with theanalysis section. For the alkylbenzene sulfonic acid or blendsof so
36、dium alkylbenzene sulfonate with sodium xylene sul-fonate or alcohol sulfate samples add to the correspondingaliquot 70 mL of deionized water, 1 mL buffer solution pH4.00, and 1 mL of 1 % Triton-X-100 solution. Proceed with theanalysis section.NOTE 2To determine the amount of sample needed for an ap
37、proxi-mately 5 to 7 mL titration of 0.0016 meq use the following equation:W 50.0016 3 MD(3)where:W = weight of sample to take for analysis, g,M = average molecular weight of the anionic active matter present,andD = approximate concentration of anionic active matter expectedweight %.10.2 To obtain ac
38、curate weights of sample, it is convenientto dissolve the anionic surfactant in deionized water and takeand aliquot corresponding to a known meq of active matter. Forexample, for an alcohol ether sulfate containing 58.1 % activesand molecular weight 441, weigh 3.0 g of sample into a 1-Lvolumetric fl
39、ask dilute with water, and take a 4-mL aliquot.Add 70 mL of deionized water, 1 mL of the correspondingbuffer solution, and 1 mL of 1 % Triton-X-100 solution.11. Analysis11.1 Titrate potentiometrically with the standardizedHyamine 1622 solution, and record the titration volume. Theendpoint is marked
40、by the point of inflection on S-shapedcurve. Autotitration systems performs the titration, determinesthe inflection point, and calculates the result.12. Calculation12.1 Calculation of percent actives in anionic surfactants asfollows:Anionics, weight % 5A 3 N 3 M 3 D 3 1000 3 100S 3 1000 3 A1(4)where
41、:A = standard Hyamine 1622 solution required for titra-tion, mL,N = normality of standard Hyamine 1622 solution,M = molecular weight of anionic surfactant,D = initial dilution of sample, mL,S = weight of sample, g, andA1 = aliquot taken for titration, mL.13. Precision and Bias1013.1 Repeatability (S
42、ingle Analyst)The standard devia-tion of results, each the average of duplicates, obtained by thesame analyst on different days, has been estimated to be 0.25 %relative at 27 df. Two such averages should be consideredsuspect, 95 % confidence level, if they differ by more than 0.70weight % relative.1
43、3.2 Reproducibility (Multilaboratory):13.2.1 Alcohol SulfateThe standard deviation of results,each the average of duplicates, obtained by analysts in differentlaboratories, has been estimated to be 0.43 % relative at 6 df.Two such averages should be considered suspect, 95 % confi-dence level, if the
44、y differ by more than 1.2 % relative.13.2.2 Alcohol Ether SulfateThe standard deviation ofresults, each the average of duplicates, obtained by analysts indifferent laboratories, has been estimated to be 0.85 % relativeat 6 df. Two such averages should be considered suspect 95 %confidence level, if t
45、hey differ by more than 2.4 % relative.13.2.3 Alkylbenzene Sulfonic AcidThe standard deviationof results, each the of average duplicates, obtained by analystsin different laboratories, has been estimated to be 0.79 %relative at 6 df. Two such averages should be consideredsuspect, 95 % confidence lev
46、el, if they differ by more than2.2 % relative.13.2.4 Alpha Olefin SulfonateThe standard deviation ofresults, each the average of duplicates, obtained by analysts indifferent laboratories, has been estimated to be 0.82 % relativeat 6 df. Two such averages should be considered suspect, 95 %confidence
47、level, if they differ by more than 2.3 % relative.13.2.5 Sodium Alkylbenzene Sulfonate/Sodium Xylene Sul-fonate (5:1)The standard deviation of results, each theaverage of duplicates, obtained by analysts in different labora-tories, has been estimated to be 0.52 % relative. Two suchaverages should be
48、 considered suspect, 95 % confidence levelif they differ by more than 1.5 % relative.13.2.6 Sodium Alkylbenzene Sulfonate/Sodium Xylene Sul-fonate (16:1)The standard deviation of results, each theaverage of duplicates, obtained by analysts in different labora-tories, has been estimated to be 0.49 %
49、relative at 6 df. Twosuch averages should be considered suspect, 95 % confidencelevel, if they differ by more than 1.3 % relative.13.2.7 Sodium Alkylbenzene Sulfonate/Sodium Xylene Sul-fonate (22:1)The standard deviation of results, each theaverage of duplicates, obtained by analysts in different labora-tories, has been estimated to be 0.45 % relative at 6 df. Twosuch averages should be considered suspect, 95 % confidencelevel, if they differ by more than 1.3 % relative.13.3 Checking Limits for DuplicatesReport the activecontent of the sample to the nearest 0.01 %
