1、Designation: D1172 95 (Reapproved 2007)D1172 15Standard Guide forpH of Aqueous Solutions of Soaps and Detergents1This standard is issued under the fixed designation D1172; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This guide covers the preparati
3、on of aqueous solutions of soaps and detergents and the determination of their pH.1.2 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associ
4、ated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior tous
5、age.2. Referenced Documents2.1 ASTM Standards:2D460 Test Methods for Sampling and Chemical Analysis of Soaps and Soap ProductsD501 Test Methods of Sampling and Chemical Analysis of Alkaline DetergentsE70 Test Method for pH of Aqueous Solutions With the Glass Electrode3. Sampling3.1 The material shal
6、l be sampled in accordance with Test Methods D460 or D501, whichever is applicable.4. Reagent4.1 Distilled Water or EquivalentDistilled water or equivalent shall be boiled thoroughly, or purged with CO2-free air, toremove CO2 and shall be protected with soda-lime or soda-asbestos (Ascarite) while co
7、oling and in storage. The pH of this watershall be between 6.2 and 7.2 at 25C. The residue on evaporation, when heated at 105C for 1 h, shall not be more than 0.5 mg/L.5. Procedure for Synthetic Detergents5.1 Preparation of SolutionsWeigh 1 6 0.001 g of the sample (see Note 1 and Note 2) and transfe
8、r to a 1-L volumetric flask.Partially fill the flask with distilled water or equivalent and agitate until the sample is completely dissolved. Make certain the soluteis completely dissolved and allow time for the evolution of dissolved gases. Fill to the calibration mark with distilled water orequiva
9、lent. Stopper the flask; mix thoroughly. The desirable condition requires the solution to come to equilibrium. Allow thesolution to equilibrate at 25 6 2.0C. The use of a temperature compensation probe may allow alternate temperatures. Recordsshould show the time interval between solution preparatio
10、n and pH measurement.NOTE 1The procedure for detergents other than soaps is applicable to some compositions that contain minor proportions of soap, provided that thesolutions do not show evidence of gelling prior to carrying out the pH measurement.NOTE 2Measurements of pH of gelled solutions lack co
11、nstancy and reproducibility. The procedure for soaps (Section 6) is designed to producesolutions that will not gel before the pH measurement is carried out. This procedure should be used for all detergent solutions, soap or nonsoap, that giveevidence of gelling or incomplete solution when prepared i
12、n accordance with 5.1. The procedure for soaps is not applicable to detergent compositionsthat are known to be chemically altered by the boiling water used in dissolving the sample, or that are intended exclusively for use in cold water.1 This guide is under the jurisdiction ofASTM Committee D12 on
13、Soaps and Other Detergents and is the direct responsibility of Subcommittee D12.15 on Physical Testing.Current edition approved Oct. 1, 2007May 1, 2015. Published October 2007July 2015. Originally approved in 1951. Last previous edition approved in 20012007 asD1172 95(2001).(2007). DOI: 10.1520/D117
14、2-95R07.10.1520/D1172-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standar
15、d and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases o
16、nly the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 Determination of pHCalibrate the pH meter and suitable electrodes. The recommend
17、ed electrodes are Fischer Accuphastcombination electrode Fisher Scientific accupHast Variable Temperature pH Combination Electrodes or Orion Ross Sure Flowelectrode or equivalent electrodes. Measure the pH of the solution while stirring.6. Procedure for Soaps (use for soaps and detergents that tend
18、to gel when added to water at room temperature)6.1 Preparation of ApparatusUse a pH meter and electrodes as defined in Test Method E70. Set the temperature control knobat 40C and standardize the assembly with a suitable buffer solution in the pH 9 to 11 range at 40C. Leave the electrode in thebuffer
19、 to maintain temperature equilibrium. Have the apparatus ready for immediate use.6.2 Preparation of SolutionWeigh 0.30 6 0.01 g of the sample (see Note 2) and transfer to a 250-mL Erlenmeyer flask. Add100 mL of boiling distilled water or equivalent that has been boiled vigorously for 15 min just pri
20、or to use. Loosely stopper theflask with a clean, neutral, one-hole stopper fitted with a suitable thermometer readable to the nearest 0.1C in the 25 to 50C rangeand so arranged that the thermometer bulb will be completely immersed in the liquid. Agitate the flask and contents to apparentlycomplete
21、solution of the sample; then cool rapidly under tap water to 43 6 0.5C. Promptly pour enough of the solution into thepH beaker to almost fill it.6.3 Determination of pHDetermine the pH of the solution at 40 6 2.0C, while stirring. The recommended electrodes areFisher Accuphast combination electrode
22、Scientific accupHast Variable Temperature Combination Electrodes or Orion Ross SureFlow electrode.ASTM 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 determ
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