1、Designation: D 5070 90 (Reapproved 2005)Standard Test Method forSynthetic Quaternary Ammonium Salts in Fabric Softenersby Potentiometric Titrations1This standard is issued under the fixed designation D 5070; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the 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 describes a potentiometric titrationprocedure for the determina
3、tion of quaternary ammonium saltsin fabric softeners. This test method is intended for the analysisof known quaternary ammonium salts such as the dialkyldimethyl quaternary ammonium compound type and the dia-midoamine based quaternary ammonium compound type.1.2 The quaternary ammonium salts conform
4、to the struc-tures shown in Fig. 1 and Fig. 2.1.3 The analytical procedure appears in the following order:SectionApparatus 5Reagents 6Preparation of standard reagents 7Standardization of hyamine solution 9Safety precautions 8Procedure for determination of dialkyl dimethyl quaternaries 10Procedure fo
5、r determination of diamidoamine based quaternaries 111.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility o
6、f regulatory limitations prior to use. See 6.4, 6.6, 6.7and Section 8 for specific warning statements.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 3049 Test Method for Synthetic Anionic Ingredient byCationic Titration3. Summary of Test Method3.1 Quaternary ammon
7、ium compounds present in fabricsofteners, as the active materials, are titrated potentiometricallyin an aqueous medium with a standard solution of sodiumlauryl sulfate using a nitrate ion-selective electrode. In thispotentiometric titration, the reaction involves the formation ofa complex between th
8、e quaternary ammonium compound andthe anionic surfactant which then precipitates.At the end point,the nitrate ion electrode appears to respond to an excess oftitrant with a potential change large enough to give a welldefined inflection in the titration curve. Alternatively thequaternary ammonium com
9、pound can be first complexed withan excess of standard sodium lauryl sulfate; the excess sodiumlauryl sulfate is titrated potentiometrically with standardHyamine 1622.34. Significance and Use4.1 This test method is used to determine the quaternaryammonium salts commonly found in fabric softeners. Qu
10、ater-nary ammonium compounds being the active ingredients infabric softeners requires accurate determination to assess thecost and performance of such compounds.5. Apparatus5.1 Autotitration Systemburet with 10 or 20 mLcapacity;4magnetic stirrer;5evaluating ruler.65.2 Electrodes(1) nitrate specific
11、ion electrode;7(2) sur-factant electrode;8(3) Ag/AgCl reference electrode.91This test method is under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergents and is the direct responsibility of Subcommittee D12.12 onAnalysis and Specifications of Soaps, Synthetics, Detergents and their C
12、omponents.Current edition approved May 1, 2005. Published June 2005. Originallyapproved in 1990. Last previous edition approved in 1997 as D 5070-90(1997).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM
13、Standards volume information, refer to the standards Document Summary page onthe ASTM website.3The sole source of supply of Hyamine 1622 known to the committee at thistime is Gallard Schlesinger Manufacturing Corp., 584 Mineola Ave., Carle Place,NY 11514. If you are aware of alternative suppliers, p
14、lease provide this informationto ASTM Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee, which you may attend.4Metrohm-Brinkman E-536, or equivalent, has been found satisfactory. Avail-able from Brinkman Instruments Inc., Cantiague Rd.,
15、 Westbury, NY 11590.5Potentiograph/E-535 and Dosimat/E-459, or equivalent, have been foundsatisfactory. Available from Brinkman Instruments Inc., Cantiague Rd., Westbury,NY 11590.6Evaluating Ruler EA-893, or equivalent, has been found satisfactory. Availablefrom Brinkman Instruments Inc., Cantiague
16、Rd., Westbury, NY 11590.7Orion Model 93.07, or equivalent, has been found satisfactory. Available fromOrion Research Inc., 529 Main St., Boston, MA 02129.8Orion Model 93.42, or equivalent, has been found satisfactory. Available fromOrion Research Inc., 529 Main St., Boston, MA 02129.9Metrohm Model E
17、A-440, or equivalent, has been found satisfactory. Availablefrom Brinkman Instruments Inc., Cantiague Rd., Westbury, NY 11590.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 Adaptors(1) coaxial adaptor, required for indicatorelec
18、trode,10(2) banana plug adaptor, required for referenceelectrode.NOTE 1To ensure electrical continuity (after assembly) shake downelectrode in the manner of a clinical thermometer. Also, the conditioningof the electrode is essential for obtaining a good break in the titrationcurve. Conditioning new
19、electrodes in 0.01 M KNO3, aqueous solution for60 min (or more) prior to use is recommended.NOTE 2Other electrodes (for example, a calomel electrode) aresuitable as the reference electrode provided they give a stable referencepotential during the titration. Reference electrodes having a ceramic or a
20、nasbestos junction tend to clog with use. Therefore, a ground-glass sleeveelectrode (such as the Metrohm EA 440 or equivalent)11is suggested.6. Reagents6.1 Hyamine 1622,3diisobutylphenoxyethoxyethyl dim-ethyl benzyl ammonium chloride monohydrate.6.2 Sodium Lauryl Sulfate,12primary standard (Note 3).
21、NOTE 3Sodium lauryl sulfate must be analyzed for purity accordingto the Reagent section of Test Method D 3049, before its use as a primarystandard.6.3 Water, type III reagent water conforming to Specifica-tion D 1193.6.4 Isopropanol, reagent grade. (WarningHighly flam-mable.)6.5 Sodium Borate Decahy
22、drate(Na2B4O710H2O), re-agent grade.6.6 Boric Acid (H3BO3), reagent grade. (WarningCauses irritation.)6.7 Sulfuric Acid (H2SO4), reagent grade. (WarningCauses severe burns on contact with skin. See Section 8.)6.8 Five percent (V/V) Sulfuric Acid SolutionUsing agraduated cylinder, transfer 80 mL of d
23、eionized water to a100-mL volumetric flask. Slowly, carefully, and with stirring,add 5 mL of concentrated sulfuric acid. Cool to room tempera-ture and dilute to the mark with water.6.9 Borate Buffer Solution pH 6.00In a 500 mL beaker,dissolve 5.0 g 6 0.02 g of sodium borate decahydrate and 7.0g 6 0.
24、02 g of boric acid in approximately 300 mL water, withstirring; adjust pH to 6.00 with 5 % sulfuric acid solution.Transfer to a 500-mL volumetric flask, mix, and dilute tovolume with water.7. Preparation of Standard Reagents7.1 Sodium Lauryl Sulfate Solution, 4 3 103NWeighaccurately 1.15 6 0.01 g of
25、 sodium lauryl sulfate to 0.1 mg;dissolve in water and dilute to a final volume of 1 L. Calculatethe normality of the solution with the following equation:Normality of sodium lauryl sulfate 5W 3 P288.38! 100!(1)where:P = purity of the sodium lauryl sulfate, weight %W = weight of sodium lauryl sulfat
26、e, g7.2 Keep the solution no longer than 1 month before makinga fresh solution.7.3 Hyamine 1622 Solution, 4 3 103NDissolve 1.85 60.5 g of Hyamine 1622 in deionized water. Transfer toa1Lvolumetric flask, and dilute to volume with water.8. Hazards8.1 All reagents and chemicals should be handled with c
27、are.Before using any chemical, read and follow all safety precau-tions and instructions on the manufacturers label or MSDS(Material Safety Data Sheet).9. Standardization of Hyamine 1622 Solution9.1 This determination must be done in triplicate. Pipet 5.00mL of the standard lauryl sulfate into a 150
28、mL beaker. Addapproximately 100 mL of deionized water and while stirringadd by pipet 2 mL of the borate buffer.9.2 The electrode should be cleaned between each titration.Asatisfactory procedure is to first rinse it with water, then withalcohol (ethyl alcohol) (Note 5) and again with water followedby
29、 wiping the surface with a soft tissue.NOTE 4The electrode can be quickly washed with ethyl alcohol whenfollowed immediately by a water rinse. Prolonged contact of the electrodewith alcohol or other organic solvent can cause failure of the electrodemembrane.9.3 Titrate potentiometrically with Hyamin
30、e 1622 andrecord the titration volume at the endpoint. The endpoint is10The Metrohm coaxial adaptor, or equivalent, has been found satisfactory forthis purpose. Available from Brinkman Instruments Inc., Cantiague Rd., Westbury,NY 11590.11Available from Brinkman Instruments Inc., Cantiague Rd., Westb
31、ury, NY11590.12Available from British Drug House, LTD, or in the U.S. from GallardSchlesinger Manufacturing Corp., 584 Mineola Ave., Carle Place, NY 11514.X= chloride or methyl sulfateR = fatty alkyl groups saturated or unsaturated, normal or branched C8C22FIG. 1 Dialkyl Dimethyl QuaternariesX= usua
32、lly methyl sulfateR = fatty alkyl groups, saturated or unsaturated, normal or branched C12C18R1= 2-hydroxyethyl,2-hydroxypropylFIG. 2 Diamidoamine Based QuarternariesD 5070 90 (2005)2marked by the point of inflection on the “S” shaped curve andit is determined by the use of the evaluating ruler.Norm
33、ality of Hyamine 1622 5N 3 5.0V(2)where:N = normality of sodium lauryl sulfate standard solution5.0 = sodium lauryl sulfate aliquot taken for titration, mLV = Hyamine 1622 solution consumed during, titration,mL10. Procedure for Determination of Dialkyl DimethylQuaternary10.1 Weigh accurately a quant
34、ity of sample to the nearest0.1 mg of quaternary ammonium compound active materialinto a 250 ml beaker.10.2 Table 1 may be used as a guide for sample weight,dilution, and aliquot. Dilution of sample must be done inisopropanol using volumetric flask and pipetes as indicated inTable 1.10.3 Add 5 mL of
35、 isopropanol. Swirl the beaker until thesample is completely dissolved.Add approximately 150 mL ofdeionized water and stir. While stirring, add, by pipet, 4 mL ofthe borate buffer solution.10.4 Pipet 10 mLof standard solution lauryl sulfate solutionwhile stirring. Transfer the solution to the autoti
36、trator. Titratepotentiometrically with standard Hyamine 1622 solution. Asthe inflection point is approached, reduce the addition rate, andcontinue titrating well past the inflection in the titration curve.(Automatic titrators can be preset to automatically slow downthe addition rate as the inflectio
37、n point is approached.) Recordthe titration volume at the endpoint. The endpoint is marked bythe point of inflection on the “S” shaped curve and it isdetermined by the use of the evaluating ruler. Typical titrationcurve of the dialkyl dimethyl ammonium salt is shown in Fig.3.10.5 Calculate the perce
38、nt dialkyl dimethyl quaternary in-gredient as follows:Dialkyl dimethyl quaternary, weight %5A 3 N1! 2 B 3 N2!# 3 M 3 D 3 100S 3 1000 3 A(3)where:A = standard sodium lauryl sulfate, mLN1= normality of standard sodium lauryl sulfateB = standard Hyamine 1622 consumed during titration,mLN2= normality of
39、 standard Hyamine 1622 solutionM = average equivalent weight of the dialkyl dimethylquaternaryD = dilution of sample, mLS = weight of sample in gramsA = aliquot of sample dilution, mL11. Procedure for Determination of Diamidoamine BasedQuaternary11.1 Weigh accurately a quantity of sample to containa
40、pproximately 0.16 meq of quaternary ammonium compoundactive material into a 250 mL beaker (Note 5). Add 5 mL ofisopropanol. Swirl the beaker until sample is completelydissolved. Add approximately 150 mL of water and stir. Whilestirring, pipet in 2 mL of the borate buffer solution. Titratepotentiomet
41、rically with standard sodium lauryl sulfate solu-tion. As the inflection point is approached, reduce the additionrate, and continue titrating well past the inflection in thetitration curve. (Automatic titrators can be preset to automati-cally slow down the addition rate as the inflection point isapp
42、roached.)NOTE 5To determine the amount of sample needed for an approxi-mately 13.7 mL titration (0.05 meq) use the following equation:W 50.005 3 MD(4)TABLE 1 Guide for Sample Weight, Dilution, and Aliquot to beUsedActiveIngredientsASample, %SampleWeight, gDilution, mL(in Isopropanol)Aliquot, mL2.5 0
43、.565 0.2810 0.1520 4.10 200 230 2.8 200 240 2.1 200 250 1.8 200 160 2.8 200 170 2.4 200 180 2.1 200 190 1.8 200 1AValues are based on an assumed molecular weight of 649 for the dialkyldimethyl quaternary.FIG. 3 Sample: Dihydrogenated-Tallow Dimethyl AmmoniumSulfate, Titrant: 0.00405N Hyamine (back t
44、itration ofsodium lauryl sulfate)AAUsing nitrate ion-selective electrodeD 5070 90 (2005)3where:W = weight of sample to be taken for analysis, gM = average equivalent weight of the quaternary ammonium saltpresentD = approximate concentration of the quaternary ammonium saltexpected, weight %11.2 To ob
45、tain accurate weights of sample, it is convenientto make up an aqueous solution (for example 250 mL) and takean aliquot corresponding to a known meq of active matter.11.3 Record the titration volume at the end point. Theendpoint is marked by the point of inflection on “S” shapedcurve and it is deter
46、mined by the use of an evaluating ruler.Typical titration curve of diamidoamine based quaternary isshown in Fig. 4.12. Calculation12.1 Calculate the percent diamidoamine based quaternaryof the sample as follows:Diamidoamine quaternary, weight %5A 3 N3 M 3 D 3 100S 3 1000 3 A(5)where:A = tandard sodi
47、um lauryl sulfate solution, mL consumedduring titrationsN = normality of standard sodium lauryl sulfate solutionM = average equivalent weight of the diamidoamine qua-ternaryD = dilution of samples, mLS = weight of sample, gA = aliquot of sample dilution, mL13. Precision13.1 The following criteria sh
48、ould be used to judge theacceptability of the results (Note 6).13.2 Repeatability (single analyst)The coefficient ofvariation of results (each the average of triplicate determina-tions), obtained by the same analyst on different days, wasestimated to be 1.24 % relative at 20 df. Two such averagessho
49、uld be considered suspect (95 % confidence level) if theydiffer by more than 3.66 % relative.13.3 Reproducibility (multilaboratory)The coefficient ofvariation of results (each the average of duplicate determina-tions) obtained by analysts in different laboratories, has beenestimated to be 2.38 % relative at 9 df. Two such averagesshould be considered suspect (95 % confidence level) if theydiffer by more than 7.62 % relative.13.4 Report the percentage of the component relative to thenearest 0.1 %. Triplicate runs which agree within 4.4 % of theamount pres
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