1、Designation:E1910/E1910M15Standard Test Method forAgricultural pH Control Agents,Measurement of pH Changeand Buffering Capacity1This standard is issued under the fixed designation E1910/E1910M;the number immediately following the designation indicates the yearof original adoption or,in the case of r
2、evision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover determining if an adjuvantmeets the definitions of an acidifier,a basic blend
3、,alkalinityagent,or buffer in Terminology E1519.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the tw
4、o systems may result in non-conformancewith the standard.1.3 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
5、of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1126 Test Method for Hardness in WaterD1193 Specification for Reagent WaterE70 Test Method for pH of Aqueous Solutions With theGlass ElectrodeE200 Practice for Preparation,Standardization,and Storageof Standard and Rea
6、gent Solutions for Chemical AnalysisE1519 Terminology Relating to Agricultural Tank Mix Ad-juvants3.Summary of Test Method3.1 Test Method A measures the change in pH of a sampleon the addition of an acidifier or a basic blend.Test Method Bmeasures the buffer capacity of the adjuvant by titration.4.S
7、ignificance and Use4.1 This test method is intended for products sold as tankmix adjuvants for use with agricultural products.4.2 Part A provides a determination of whether the pHmodification characteristics of the adjuvant tested meet thedefinition of an acidifier,alkalinity agent,or a basic blend
8、inTerminology E1519.Part B provides a measure of the buffercapacity of the adjuvant.This can be used to estimate theamount of a buffer that will be required to keep a spray solutionat the desired pH.4.3 Other pH standards can be used(see Test Method E70)as long as the pHs measured are not outside th
9、e range of thestandards used.4.4 If samples of the material to be used in a particularapplication are available,the first method can be used todetermine what adjuvant rate is required to obtain the desiredpH.The ability of an adjuvant to adjust the pH of a particularsystem will depend on the initial
10、 pH before addition.4.5 The second method can be used to determine the amountof an adjuvant required to change the pH of a quantity of spraysolution to the required value(see Note 1).NOTE1Many acidifiers and basic blends also are buffers,so the pHchange does not provide a useful measure of buffer ca
11、pacity.5.Apparatus5.1 pH Meter,accurate to 0.01 unit.5.2 Combination Glass/Calomel Electrode,or separate glassand calomel electrodes or other suitable pH electrode system.5.3 Beakers,250 mL.5.4 Magnetic Stirrer,120 to 1200 rpm,or equivalent.5.5 Magnetic Stir Bar,1 in.(2.5 cm)in length and38in.(0.95
12、cm)in diameter.5.6 Burette,50 mL,Class A.6.Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended that1These test methods are under the jurisdiction of ASTM Committee E35 onPesticides,Antimicrobials,and Alternative Control Agentsand
13、are the directresponsibility of Subcommittee E35.22 on Pesticide Formulations and DeliverySystems.Current edition approved Oct.1,2015.Published November 2015.Originallyapproved in 1997.Last previous edition approved in 2009 as E1910/E1910M 04(2009).DOI:10.1520/E1910_E191M-15.2For referenced ASTM sta
14、ndards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-
15、2959.United States1 all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Societywhere such specifications are available.6.2 Purity of Water Unless otherwise indicated,referenceto water shall be understood to mean reagent water,Type IV,asd
16、efined by Specification D1193(see Note 2).NOTE2Type IV grade reagent water may be prepared by distillation,ion exchange,reverse osmosis,electrodialysis,or a combination thereof.6.3 Synthetic Hard Water Stock,transfer 12.14 g of anhy-drous calcium chloride(CaCl2)and 5.55 g of magnesiumchloride hexahydrate(MgCl26H2O)to a 1000mL volumetricflask.Dissolve the reagents with approximately 750 mL ofwater and equilibrate to 20C.Dilute the solution to 1000 mLtotal volume with water at 20C,stopper the flas