ASTM E1945-2002 Standard Test Method for Percent Dispersibility《农药弥散率的标准试验方法》.pdf

1、Designation: E 1945 02Standard Test Method forPercent Dispersibility1This standard is issued under the fixed designation E 1945; 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 parentheses ind

2、icates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is used to determine the percentdispersibility of dry pesticide formulations.1.2 This standard does not purport to address all of thesafety co

3、ncerns, 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 of regulatory limitations prior to use. For specificprecautionary statements see Section 7.2. Referenced Documents2.1 A

4、STM Standards:2D 1126 Test Method for Hardness in WaterD 1193 Specification for Reagent Water3. Summary of Test Method3.1 A known amount of dry pesticide formulation is addedto a 250-mL mixing cylinder that has been filled to volumewith standard water. The mixing cylinder is then stoppered andinvert

5、ed 30 times in two minutes. The mixing cylinder isallowed to stand for 1 min. After 1 min the top 225 mL isdrawn off and the remaining suspension is dried. The residueweight will determine percent dispersibility.4. Significance and Use4.1 This test method is designed specifically for dry formu-latio

6、ns.4.2 This test method may not be applicable to all dryformulations such as those containing either liquid technicalsor ingredients that rise to the top upon separation.4.3 This test method may not be applicable to those tech-nicals that decompose below the drying temperature.4.4 This test method s

7、hould be run in duplicate.4.5 Products containing water soluble or volatile compo-nents may result in errors.5. Apparatus5.1 Balance, top loading, with an accuracy of 60.01 g orbetter.5.2 Gravity Oven.5.3 Weighing Dish, 150 mL capacity or greater.5.4 Vacuum Apparatus, see Fig. 1, equipped with a ven

8、tedstopper.5.5 Mixing Cylinder, stoppered, 250-mL, flat bottom, KI-MAX series 20 039 or equivalent.5.6 Timer, adjustable, with an accuracy of 61 second.5.7 Weighing Dish, aluminum (57 3 18 mm) or petri dish orequivalent.5.8 Filtering Flask, heavy wall, 500 mL, Kimax Series 27060 or equivalent.6. Rea

9、gents (Test Water)6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, 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.

10、36.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water, Type IV, asdefined by Specification D 1193.NOTE 1Type IV grade reagent water may be prepared by distillation,ion exchange, reverse osmosis, electrodialysis, or a combination thereof.6.3 Synth

11、etic Hard Water Stock, transfer 12.14 g of anhy-drous calcium chloride (CaCl2) and 5.55 g of magnesiumchloride hexahydrate (MgCl26H2O) to a 1000-mL volumetricflask. Dissolve the reagents with approximately 750 mL ofwater and equilibrate to 20C. Dilute the solution to 1000 mLtotal volume with water a

12、t 20C, stopper the flask, and mix thesolution thoroughly. This mixture is equivalent to 13 680 ppmas calcium carbonate (CaCO3) and is based on a compositionalratio of 4:1 calcium carbonate to magnesium carbonate.6.3.1 Soft Water, equivalent to a total hardness of 34.2 ppmas calcium carbonate (CaCO3)

13、. Transfer 2.50 mL of synthetic1This practice is under the jurisdiction of ASTM Committee E35 on Pesticidesand is direct responsibility of Subcommittee E35.22 on Pesticide Formulation andApplication Systems.Current edition approved Nov. 10, 2002. Published January 2003. originallyapproved in 1998. l

14、ast previous edition approved in 1998 as E194598.2For 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 standards Document Summary page onthe ASTM website.3Reagent Che

15、micals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDF Ltd., Poole, Dorset, U.K., and the United States Pharmacopoeiaand Natio

16、nal Formulary, U.S. Pharmaceutical Convention, Inc., (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.hard water stock by pipet to a 1000-mL volumetric flask anddilute to volume with water at 20C. Mix solution tho

17、roughly.NOTE 2It is recommended that total hardness be checked in accor-dance with Test Method MT-73, CIPAC 1, EDTA titration.4An alternatemethod is provided in Test Methods D 1126 where the value is representedas CaCO3. A value within 65 % of the nominal hardness value isacceptable.6.3.2 Hard Water

18、, equivalent to a total hardness of 342 ppmas calcium carbonate (CaCO3). Transfer 25.0 mL of synthetichard water stock by buret to a 1000-mL volumetric flask anddilute to volume with water at 20C. Mix this solutionthoroughly (see Note 2).6.3.3 Extra-hard Water, equivalent to a total hardness of1000

19、ppm as calcium carbonate (CaCO3). Transfer 73.1 mL ofsynthetic hard water stock by buret to a 1000-mL volumetricflask and dilute to volume with water at 20C. Mix this solutionthoroughly (see Note 2).6.3.4 Other Test WatersOther synthetic waters can beprepared by using the following calculation:Desir

20、ed Water Hardness 4 13.680 5milliliters of synthetichard water stock at 20Ctobediluted volumetrically to 1000 mLwith water at 20C. (1)6.4 Other CarriersCarriers other than water may be usedwhen appropriate.7. Safety Precautions7.1 Before testing, read the precautionary statements on theproduct label

21、 or the Material Safety Data Sheet (MSDS), orboth. Take proper precautions to prevent skin contact andinhalation of the fines or vapors, or both. Take care to preventcontamination of the surrounding area. Always wear theappropriate safety equipment and, where indicated, wear res-piratory devices app

22、roved by the National Institute of Occu-pational Safety and Health (NIOSH) for the product beingtested.8. Procedure8.1 Each sample should be run in duplicate.8.1.1 Weigh a 2.5-g sample into a weighing dish. Record thesample weight (W1) to an accuracy of 6 0.01 g.8.1.2 Fill a 250-mL mixing cylinder t

23、o volume with testwater and equilibrate to 20C 6 2C, (see Note 3).NOTE 3Other temperatures may be examined as defined by actualfield use applications.8.1.3 Transfer the sample from 8.1.1 to the mixing cylinder.8.1.4 Stopper and invert the cylinder 30 times in twominutes.8.1.5 Let the mixing cylinder

24、s stand for 1 min.8.1.6 Remove 225 mL from the mixing cylinder using thevacuum apparatus in accordance with Section 5.4. Ensure thatthe tip of the suction tube remains slightly below the liquidsurface while removing the 225 mL. Take care not to disturbthe bottom 25-mL layer.8.1.7 Record the tare wei

25、ght of the weighing dish to anaccuracy of 60.01 g.8.1.8 Gently swirl the remaining suspension to loosen thehard-packed material. Transfer quantitatively to the weighingdish. Rinse the cylinder with additional test water if necessary.8.1.9 Dry the weighing dish containing the residue from8.1.8 in a 5

26、0C gravity oven to a constant weight.8.1.10 Weigh the dish from 8.1.9 to an accuracy of 6 0.01g and subtract the tare weight to determine the dried residueweight (W2).9. Disposal of Sample9.1 After testing, store all materials in a safe manner anddispose of used material in accordance with product l

27、abeldirections or MSDS, or both.10. Calculation10.1 Calculate % dispersibility of the WG as follows:% Dispersibility 51093W12 W2! 3 100W1!(2)where:W1= sample weight and,W2= dried residue weight.4“Physico-Chemical Methods for Technical and Formulated Pesticides,” CIPACHandbook, vol F, compiled by W.

28、Dorbat and A. Martin, Collaborative InternationalPesticide Analytical Council Ltd., Great Britain, 1995.FIG. 1 Vacuum ApparatusE194502211. Report11.1 Report percent dispersibility, ambient temperature, andwater hardness.12. Precision and Bias12.1 RepeatabilityTwo results obtained by the same ana-lys

29、t should be considered suspect if they differ by more than2.0 % absolute.12.2 ReproducibilityTwo results obtained by analysts indifferent laboratories should be considered suspect if theydiffer by more than 5.0 % absolute.12.3 BiasThis test method has no bias because the valueof dispersibility is de

30、fined only in terms of this test.13. Keywords13.1 dispersion; dry flowable (DF); dry flowable test meth-ods; percent dispersibility; water dispersible granules (WG)(WDG); water dispersible granules test methods; wettablegranules test methodsASTM International takes no position respecting the validit

31、y 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, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject

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33、s. 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 shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard i

34、s 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).E1945023