ASTM_D_1279_-_82_1994_scan.pdf

I-0759510 0543243 79T m Designation:D 1279-82(Reapproved 1994)Standard Test Method for Buffering Action of Metal Cleaners This standard is issued under the fixed designation D 1279;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number m parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an titorial change since the last revision or reapproval.1.Scope 1.l This test method covers the determination of the buffering action of metal cleaners.1.2 This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility 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.2.Referenced Document 2.1 ASTM Standard:E 70 Test Method for pH of Aqueous Solutions with the Glass Electrode2 3.Significance and Use 3.1 This test method is used to compare the buffering capacity of alkaline metal cleaners in terms of a buffer index,that is,the volume of standard acid needed to obtain a specified pH reduction.The users will define the buffer index.4.Terminology 4.1 Dejinitions:4.1.1 buffer action-the resistance of a solution to change in pH.4.1.2 buffering capacity-the ability of an alkaline solu-tion to absorb acidic material without marked change in PH.4.1.3 buffer index-the millilitres of 0.5 N hydrochloric acid required to decrease the initial pH of the solution either*Ttus test method is under the jurisdiction of ASTM Committee D-12 on Soaps and Other Detergents and is the direct responsibility of Subcommittee D12.16 on Hard Surface Cleaning.Current edition approved April 30,1982.Published June 1982.Originally published as D 1279-53.Last prewous&tion D 1279-57(1977).*Annual Book of ASTM Standards,Vol 15.05.1 pH unit or some definite change in pH,as agreed upon between the seller and the purchaser.Examples of change in pH ranges are as follows:4.1.3.1 From initial pH of a solution to pH of 12.0,4.1.3.2 From pH 12.0(or initial pH if between 11 and 12)down to pH 11.O,and 4.1.3.3 From pH 11.0 down to pH 10.0.5.Procedure 5.1 Prepare 500 mL of a solution of 3.75 g(1 o&al)of the cleaner in distilled water.5.2 Transfer 100 mL of the solution at 25 f 1C to a 400-mL beaker.5.3 Determine the initial pH in accordance with Test Method E 70,using the high pH(low-sodium-error)elec-trode.5.4 Add 1.O-mL increments of 0.5 N HCl to the solution.Bring the solution to equilibrium after each acid addition,and record the pH.Add further l.O-mL increments of 0.5 N HCl,and record the corresponding pH values.Terminate the additions of HCl at a pH of 9.6.Calculation 6.1 Plot the curve for pH versus aliquots of 0.5 N HCl.6.2 Calculate the buffer index as follows:Buffer index=mL of 0.5 N HCI to reduce pH to 10 or Buffer index=(I)mL of 0.5 N HCl to reduce initial pH to 12.0(2)mL of 0.5 N HCl to reduce pH from 12 to 11(3)mL of 0.5 N HCl to reduce pH from 11 to 10 7.Precision and Bias 7.1 Since the conditions for testing are to be selected by the user,and therefore vary,no precision or bias data have been obtained.The American Society for Testing and Materials takes no pition respecting the valfdlty of any palent nghts assertad m connection with any item mentroned m this standard.Users of this standard are express/y advised that determmatron of the validity of any such parent rights,and the risk of infrmgement of such rights,are entuefy their own responsibility.This standard is subject to revision at any lime by the responsible technical committee and must be reviewed every five years and if not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standards and should tm addressed to ASTM Headquarters.Your comments will receive careful consrderadon at a meeting of the responsible technical commiftee,which you may attend.If you fee/that your comments have not received a farr hearing you should make your views known to the ASTM Committee on Standards,1916 Race St.,Philadelphia,PA 197 03.110 NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.