1、Designation: D 5806 95 (Reapproved 2003)Standard Test Method forDisinfectant Quaternary Ammonium Salts by PotentiometricTitration1This standard is issued under the fixed designation D 5806; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 covers a potentiometric titration pro-cedure for determining active matter in dis
3、infectant quaternaryammonium salts. This test method is intended for the analysisof quaternary ammonium salts used as disinfectants, and onlyapplies to the following commonly used quaternary ammoniumsalts: n-alkyldimethylbenzylammonium chloride (see Fig. 1),cetyltrimethylammonium chloride, and a ble
4、nd of n-octyldecyldimethylammonium chloride, di-n-octyl dimethylammoniumchloride, and di-n-decyldimethyl ammonium chloride (see Fig.2). Also, this test method can be applied to the analysis ofdisinfectant type products where the formula ingredients areknown and the quaternary ammonium salt is one of
5、 the above.Interferences such as amines oxides and betaines present indisinfectant formulations were not tested.1.2 This disinfectant quaternary ammonium salt conformsto the structures in Fig. 1 and Fig. 2.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wi
6、th its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificprecautionary information, see Section 8.2. Referenced Documents2.1 ASTM Standards:D 459 Termino
7、logy Relating to Soaps and Other Deter-gents2D 1193 Specification for Reagent Water3D 1681 Test Method for Synthetic Anionic Active Ingredi-ent in Detergents by Cationic Titration Procedure2D 3049 Test Method for Synthetic Anionic Ingredient byCationic Titration2E 180 Practice for Determining the Pr
8、ecision Data ofASTM Methods for Analysis and Testing of IndustrialChemicals43. Terminology3.1 DefinitionsSee Terminology D 459.4. Summary of Test Method4.1 Disinfectant type quaternary ammonium compoundspresent, as the active materials in disinfectant type products aretitrated potentiometrically in
9、an aqueous medium with astandard solution of sodium lauryl sulphate using a nitrateion-selective electrode or a surfactant electrode (see also TestMethod D 1681). In this potentiometric titration, the reactioninvolves the formation of a complex between the disinfectantquaternary ammonium compound an
10、d the anionic surfactantwhich then precipitates. At the end point, the nitrate ionelectrode or surfactant electrode appears to respond to anexcess of titrant with a potential change large enough to give awell defined inflection in the titration curve.5. Significance and Use5.1 This test method is us
11、ed to determine the percent activesin each type of the disinfectant quaternary ammonium salts,and also in the disinfectant products. Quaternary ammoniumcompounds being the active ingredients in disinfectant-typeproducts require accurate determination to assess the cost andantimicrobial performance o
12、f such products.1This test method is under the jurisdiction of ASTM Committee D12 on Soapsand Other Detergents and is the direct responsibility of Subcommittee D12.12 onAnalysis of Soaps and Synthetic Detergents.Current edition approved Oct. 10, 1995. Published December 1995.2Annual Book of ASTM Sta
13、ndards, Vol 15.04.3Annual Book of ASTM Standards, Vol 11.01.4Annual Book of ASTM Standards, Vol 15.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Autotitration System,5with 10-mL buret capacity, or20-mL buret capa
14、city, magnetic stirrer,6evaluating ruler,7titroprocessor8with 10-mL buret capacity or equivalent autoti-tration system.6.2 Nitrate Specific Ion Electrode,9or surfactant elec-trode,10or equivalent. Silver/silver chloride reference elec-trode.116.3 Metrohm Coaxial Adaptor, required for indicator elec-
15、trode.12Banana plug adaptor, required for reference electrode.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 el
16、ectrodes in 0.004 M sodium lauryl sulfate,aqueous solution for 60 min (or more) prior to use is recommended. Alsoapplies to the nitrate or surfactant electrode.NOTE 2Other electrodes (for example, calomel electrodes) are suit-able as the reference electrode provided they give a stable referencepoten
17、tial during the titration. Reference electrodes having a ceramic or anasbestos junction tend to clog with use. Therefore, a ground-glass sleeveelectrode13is suggested.7. Reagents7.1 Sodium Lauryl Sulfate,14primary standard (see Note3).7.2 Standardize with Hyamine 1622, dried previously at105C for 1
18、h.NOTE 3Sodium lauryl sulfate must be analyzed for purity accordingto the Reagent section of Test Method D 3049 before using as a primarystandard.7.3 Water, Type III, reagent water conforming to Specifica-tion D 1193.7.4 Isopropanol, reagent grade. (WarningHighly flam-mable.)7.5 Sodium Borate Decahy
19、drate, (Na2B4O710H2O), re-agent grade.7.6 Boric Acid,(H3BO3), reagent grade. (WarningCauses irritation.)7.7 Sodium Hydroxide, (NaOH), reagent grade.(WarningCauses severe burns on contact with skin.)7.8 Sodium Hydroxide, 2N SolutionDissolve 40 g ofsodium hydroxide in approximately 300 mL of deionized
20、 waterwith stirring. Transfer to a 500-mL volumetric flask, dilute tovolume with deionized water, and mix well.7.9 Borate Buffer SolutionDissolve 1.5 g Na2B4O710H2O and 1.0 g H3BO3in approximately 200 mL deionizedwater, with stirring; adjust pH to 9.5 with 2N HaOH, transferto a 1000-mL volumetric fl
21、ask, mix and dilute to volume withdeionized water.7.10 Octoxynol-9 Nonionic Surfactant.157.11 Triton Solution, 1 %Pipet 1 mL of the octoxynol-9nonionic surfactant and transfer to a 100-mL volumetric flaskdiluted to volume with deionized water.7.12 Sodium Lauryl Sulfate Solution, 8 3 103NWeighaccurat
22、ely 2.42 6 0.01 g of sodium lauryl sulfate to nearest 0.1mg; dissolve in water and dilute to a final volume of 1 L.Determine the normality of the solution with the followingequation:5Metrohm-Brinkmann E-536, or equivalent, has been found satisfactory. Avail-able from Brinkmann Instruments Inc., Cant
23、iague Rd., Westbury, NY 11590.6Potentiograph/E-535 and Dosimat/E-459, or equivalent, have been foundsatisfactory. Available from Brinkmann Instruments Inc.7Evaluating Ruler EA-893, or equivalent, has been found satisfactory. Availablefrom Brinkmann Instruments Inc.8Metrohm-Brinkmann Titroprocessor 6
24、70 has been found satisfactory. Availablefrom Brinkmann Instruments Inc.9Orion Model 93.07, or equivalent, has been found satisfactory. Available fromOrion Research Inc., 529 Main St., Boston, MA 02129.10Orion Model 93.42, or equivalent, has been found satisfactory. Available fromOrion Research Inc.
25、11Metrohm Model EA-440, or equivalent, has been found satisfactory. Availablefrom Brinkmann Instruments Inc.12The Metrohm coaxial adaptor, or equivalent, has been found satisfactory forthis purpose. Available from Brinkmann Instruments Inc.13The Metrohm WA-440, or equivalent, has been found satisfac
26、tory. Availablefrom Brinkmann Instruments Inc.14Available from British Drug House, LTD, or in the U.S.A. from GallardSchlesinger Chemical Manufacturing Corp., 584 Mineola Ave., Carle Place, NY11514.15Triton-X-100 has been found satisfactory. Available from Fisher Scientific Cat.#BP151-100.where:X= c
27、hloride, andR = aliphatic, normal C8C22.FIG. 1 n-alkyldimethylbenzylammonium chloride and n-alkyldimethylethylbenzylammonium chloridewhere:X= chloride, andR = aliphatic, normal C8C22.FIG. 2 Dialkyldimethyl quaternariesD 5806 95 (2003)2Normality of sodium lauryl sulfate 5W 3 P288.38! 100!(1)where:P =
28、 purity of the sodium lauryl sulfate, weight %, andW = weight of sodium lauryl sulfate, g.Keep the solution no longer than 1 month before making afresh solution.8. Hazards8.1 Handle all reagents and chemicals with care. Beforeusing any chemical, read and follow all safety precautions andinstructions
29、 of the manufacturer label or MSDS (MaterialSafety Data Sheet).9. Procedure for Determination of DisinfectantQuaternary Ammonium Salt or Disinfectant TypeProduct9.1 Weigh accurately a quantity of sample to contain ap-proximately 0.056 meq/10 mL of disinfectant quaternaryammonium compound active mate
30、rial into a 200-mL volumet-ric flask (Note 4). Dilute to volume with deionized water. Mixwell. Pipet the corresponding aliquot, then add approximately150 mL of water and stir. While stirring, pipet in 10 mL of theborate buffer solution, 2 mL of isopropanol, and 2 mL of 1 %octoxynol-9 nonionic surfac
31、tant. Titrate potentiometricallywith standard sodium lauryl sulfate solution. As the inflectionpoint is approached, reduce the addition rate and continuetitrating well past the inflection in the titration curve. (Auto-matic titrators can be preset to automatically slow down theaddition rate as the i
32、nflection point is approached.)NOTE 4To determine the amount of sample needed for an approxi-mately 5 to 7 mL titration of 0.0056 meq use the following equation:W 50.0056 3 MD(2)where:W = weight of sample to be taken for analysis, g,M = average molecular weight of the anionic active matter present,a
33、ndD = approximate concentration of anionic active matter expected,weight %.9.2 To obtain accurate sample weights of sample, it isconvenient to dissolve the disinfectant quaternary ammoniumcompound in deionized water and take an aliquot correspond-ing to a known meq of active matter. For example, for
34、 adisinfectant quaternary ammonium compound containing28.0 % actives molecular weight 335, weigh 1.3 of sample intoa 200-mL volumetric flask, dilute with water, and take a 10-mLaliquot. Add 150 mL of water, 10 mL of borate buffer solution,2 mL of 1 % Triton solution, and 2 mL of isopropanol. Titrate
35、with the standard 0.008 N solution of sodium lauryl sulfate.9.3 Record the titration volume at the end point. Theendpoint is marked by the point of inflection on “S” shapedcurve and it is determined by the use of metrohm evaluatingruler. A typical titration curve of a disinfectant quaternaryammonium
36、 compound is shown in Fig. 3.10. Calculation10.1 Calculate the percent actives in the sample as follows:Disinfectant quaternary ammonium compound weight % 5 (3)A 3 N3 M 3 D 3 100S 3 1000 3 A1where:A = standard sodium lauryl sulphate solution consumedduring titration, mL,N = normality of standard sod
37、ium lauryl sulfate solution,M = average equivalent weight of the disinfectant quater-nary ammonium compound,S = weight of sample, g,D = initial sample dilution, mL (that is, 200 mL), andA1= aliquot taken for titration (that is, 10 mL).11. Precision and Bias11.1 Repeatability (Single Analyst)The stan
38、dard deviationof results (each the average of duplicates), obtained by thesame analyst on differed days, has been estimated to be 0.25 %absolute at 23 df. Two such averages should be consideredsuspect (95 % confidence level) if they differ by more than0.80 % absolute. (See Practice E 180.)11.2 Repro
39、ducibility (Multilaboratory):11.2.1 n-Alkyldimethylbenzylammonium ChlorideThestandard deviation of results (each the average of duplicates),obtained by analysts in different laboratories, has been esti-mated to be 0.24 % absolute at 23 df. Two such averagesshould be considered suspect (95 % confiden
40、ce level) if theydiffer by more than 0.8 % absolute.11.2.2 Cetyltrimethylammonium ChlorideThe standarddeviation of results (each the average of duplicates), obtainedby analysts in different laboratories, has been estimated to be0.38 % absolute at 23 df. Two such averages should beconsidered suspect
41、(95 % confidence level) if they differ bymore than 1.4 % absolute.11.2.3 Blend of n-octyldecyldimethylammonium Chloride,Di-n-decyldimethyl Ammonium Chloride and Di-n-decyldimethylammonium ChlorideThe standard deviation ofresults (each the average of duplicates), obtained by analysts indifferent labo
42、ratories, has been estimated to be 1.9 % absoluteat 23 df. Two such averages should be considered suspect(95 % confidence level) if they differ by more than 4.4 %absolute.NOTE 5The precision data were derived from results of the coopera-tive tests by six laboratories on the following disinfectant qu
43、aternaryammonium salts: (equivalent weights in parentheses are based on com-mercial disinfectant quaternary ammonium salts)n-octyldecyldimethylammonium chloride, di-n-octyldimethylammoniumchloride, and di-n-decyldimethylammonium chloride (335),n-alkyldimethylbenzylammonium chloride (358), cetyltrime
44、thylammo-nium chloride (320).D 5806 95 (2003)3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, a
45、nd the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revis
46、ion of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you s
47、houldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be ob
48、tained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).FIG. 3 Sample: n-alkyldimethylbenzylammonium chlorideTitrant: 0.008N Sodium lauryl sulfate. Using nitrate ion selective electrode.D 5806 95 (2003)4
