1、Designation: E 1910 04Standard Test Method forAgricultural pH Control Agents1This standard is issued under the fixed designation E 1910; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenth
2、eses indicates the year of last reapproval. Asuperscript epsilon (e) 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, alkalinityagent, or buffer in Terminology E 15
3、19.1.2 The values stated in both inch-pound and SI units are tobe regarded separately as the standard. The values given inparentheses are provided for information only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of
4、 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 Documents2.1 ASTM Standards:2D 1126 Test Method for Hardness in WaterD 1193 Specification for Reagent WaterE 70 Test Method for pH of
5、 Aqueous Solutions With theGlass ElectrodeE 200 Practice for the Preparation, Standardization, andStorage of Standard and Reagent Solutions for ChemicalAnalysisE 1519 Terminology Relating to Agricultural Tank MixAdjuvants3. Summary of Test Method3.1 Test Method A measures the change in pH of a sampl
6、eon the addition of an acidifier or a basic blend. Test Method Bmeasures the buffer capacity of the adjuvant by titration.4. Significance 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 t
7、he pHmodification characteristics of the adjuvant tested meet thedefinition of an acidifier, alkalinity agent, or a basic blend inTerminology E 1519. 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 sp
8、ray solutionat the desired pH.4.3 Other pH standards can be used (see Test Method E 70)as long as the pHs measured are not outside the 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
9、 rate is required to obtain the desiredpH. The ability of an adjuvant to adjust the pH of a particularsystem will depend on the initial 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
10、value (see Note 1).NOTE 1Many acidifiers and basic blends also are buffers, so the pHchange does not provide a useful measure of buffer capacity.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 elect
11、rode 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 and38 in.(0.95 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 indicat
12、ed, it is intended thatall 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 I
13、V, asdefined by Specification D 1193 (see Note 2).NOTE 2Type 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 magnesium
14、chloride hexahydrate (MgCl26H2O) to a 1000mL volumetric1These test methods are under the jurisdiction of ASTM Committee E35 onPesticides and Alternative Control Agents and are the direct responsibility ofSubcommittee E35.22 on Pesticide Formulations and Delivery Systems.Current edition approved Oct
15、1, 2004. Published October 2004. Originallyapproved in 1997. Last previous edition approved in 2000 as E 1910 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the
16、 standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.flask. Dissolve the reagents with approximately 750 mL ofwater and equilibrate to 20C. Dilute the solution to 1000 mLtotal volume wit
17、h water at 20C, stopper the flask and mix thesolution thoroughly. This mixture has a hardness equivalent to13680 ppm of calcium carbonate (CaCO3) and is based on acompositional ratio of 4:1 calcium to magnesium.6.4 Standard Hard Water, equivalent to a total hardness of342 ppm of calcium carbonate (C
18、aCO3). Transfer 25 mL ofsynthetic hard water stock by pipette to a 1000 mL volumetricflask and dilute to volume with water at 20C. Mix the solutionthoroughly (see Note 3).NOTE 3It is recommended that the total hardness be checked inaccordance with Test Method MT-73, CIPAC 1, EDTA titration.3Analtern
19、ate method is provided in Test Method D 1126, where the value isrepresented as CaCO3. A value within 6 5 % of the nominal hardnessvalue is acceptable.6.5 pH Reference Solution, pH 4.00.6.6 pH Reference Solution, pH 7.00.6.7 pH Reference Solution, pH 10.00.6.8 0.05 N Sodium Hydroxide, prepared accord
20、ing to Prac-tice E 200, or the equivalent.6.9 0.05 N Sulfuric Acid, prepared according to PracticeE 200, or the equivalent.6.10 0.05 N Hydrochloric Acid, prepared according toPractice E 200, or the equivalent.TEST METHOD AMEASUREMENT OF pHCHANGE OF STANDARD HARD WATER7. Procedure7.1 The pH meter sho
21、uld be turned on and allowed to warmup according to manufacturers instructions.7.2 Calibrate the pH meter according to manufacturersdirections using the pH 4.00 and pH 7.00 reference standardsfor an acidifier or the pH 7.00 and pH 10.00 referencestandards for a basic blend or alkalinity agent (see N
22、ote 4).Place the standards in a 250 mL beaker and stir with themagnetic stirrer and stir bar, while the measurements are beingmade. Care should be taken to thoroughly wash the electrodeswith water between measurements.NOTE 4Other or additional reference standards may be used (see TestMethod E 70) as
23、 long as the pHs measured are not outside the range of thestandards used.7.3 Place a clean stir bar and 100 mL of standard hard water(see Note 5) in a 250 mL beaker. Begin stirring with themagnetic stirrer. After carefully rinsing the electrodes, placethem in the water and measure and record the pH,
24、 whichshould be between 5.5 and 7.NOTE 5Other water samples can be used if appropriate. In this casethe initial pH may not be between 5.5 and 7. For specific applications theactual water to be used is preferred.7.4 Add 2 mL of the adjuvant to be tested to the beaker andallow to stir for 5 min. Other
25、 dilutions may be used if specifiedon the product label.7.5 Record the new pH value.7.6 Remove the electrodes from the solution, clean them,and store them properly. Dispose of the solution properly.8. Report8.1 Report the initial and final pH values (see Note 6).NOTE 6For an acidifier the final pH s
26、hould be lower than the initial.For a basic blend or alkalinity agent it should be higher.9. Precision and Bias9.1 The precision and bias of this test method has not beendetermined.TEST METHOD BBUFFER CAPACITY10. Procedure10.1 Turn on and warm up the pH meter according tomanufacturers directions.10.
27、2 Calibrate the pH meter according to manufacturersdirections using the pH 4.00 and pH 7.00 reference standardsfor an acidifier or acidic buffer, or the pH 4.00 and pH 10.00reference standards for a basic blend, alkaline buffer, oralkalinity agent (see Note 7). The standards should be placed ina 250
28、 mL beaker and stirred with the magnetic stirrer and stirbar, while the measurements are being made. Care should betaken to thoroughly wash the electrodes with water betweenmeasurements.NOTE 7Other or additional reference standards may be used (see TestMethod E 70) as long as the pHs measured are no
29、t outside the range ofthe standards used.10.3 Place a clean stir bar and 100 mL of standard hardwater (see Note 8) in a 250 mL beaker. Begin stirring with themagnetic stirrer. After carefully rinsing the electrodes, placethem in the water and measure and record the pH, whichshould be between 5.5 and
30、 7.NOTE 8Other water samples can be used if appropriate. In this casethe initial pH may not be between 5.5 and 7. For specific applications theactual water to be used is preferred.10.4 For an acidifier or acidic buffer fill the burette with0.05 N sodium hydroxide. For a basic blend, alkaline buffer,
31、 oralkalinity agent, fill the burette with 0.05 N hydrochloric acidor 0.05 N sulfuric acid. Record the initial volume.10.5 Weigh 2 6 0.1 g to the nearest 0.01 g of the adjuvantto be tested (see Note 9) into the beaker and allow to stir for 5min.NOTE 9If necessary for a particular product, the sample
32、 size shouldbe adjusted to give a titration volume between 5 and 40 mLs.10.6 Record the pH versus volume titration curve. Thecurve should be measured carefully in the region of the initialwater pH.10.7 From the titration curve determine the volume oftitratant required to return the sample pH to its
33、initial value.11. Calculation11.1 Calculate the number of milliequivalents of acid (for anacidifier or acidic buffer) or base (for a basic blend, alkalinebuffer, or alkalinity agent) per gram of product. Multiply the3“Analysis of Technical and Formulated Pesticides,” CIPAC Handbook, Vo l 1 ,compiled
34、 by Ashworth, R de B., Henriet, J., Lovett, J.F., Collaborative InternationalPesticide Analytical Council Ltd., Great Britain, 1970.E1910042titration volume times the concentration of the titratant solu-tion. Divide this result by the product weight.meq of acid or baseGram of A5T 0.05 meq/mL!S(1)Whe
35、re:meq = MilliequivalentsA = AdjuvantS = Sample Weight (g)T = Titration Volume (mL)12. Report12.1 Report the number of milliequivalents of acid (for anacidifier or acidic buffer) or base (for a basic blend, alkalinebuffer, or alkalinity agent) per gram of adjuvant.13. Precision and Bias13.1 The prec
36、ision and bias of this test method has not beendetermined.14. Keywords14.1 acidifier; adjuvant; agricultural adjuvant; alkalinityagent; basic blend; buffer; pHASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this stand
37、ard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and 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 review
38、ed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision 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
39、 technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake 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 obtained 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).E1910043
