ASTM_E_1945_-_02_2008.pdf

Designation:E194502(Reapproved 2008)Standard Test Method forPercent Dispersibility1This standard is issued under the fixed designation E1945;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 indicates the year of last reapproval.Asuperscript epsilon()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 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 of regulatory limitations prior to use.For specificprecautionary statements see Section 7.2.Referenced Documents2.1 ASTM Standards:2D1126 Test Method for Hardness in WaterD1193 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 andinverted 30 times in 2 min.The mixing cylinder is allowed tostand for 1 min.After 1 min,the top 225 mL is drawn off andthe remaining suspension is dried.The residue weight willdetermine percent dispersibility.4.Significance and Use4.1 This test method is designed specifically for dry formu-lations.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 should 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 ventedstopper.5.5 Mixing Cylinder,stoppered,250-mL,flat bottom.5.6 Timer,adjustable,with an accuracy of 61 s.5.7 Weighing Dish,aluminum(57 18 mm)or petri dish orequivalent.5.8 Filtering Flask,heavy wall,500 mL.6.Reagents(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.36.2 Purity of WaterUnless otherwise indicated,referenceto water shall be understood to mean reagent water,Type IV,asdefined by Specification D1193.NOTE1Type 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 1000-mL volumetric1This test method is under the jurisdiction of ASTM Committee E35 onPesticides,Antimicrobials,and Alternative Control Agents and is direct responsi-bility of Subcommittee E35.22 on Pesticide Formulations and Delivery SystemsCurrent edition approved Oct.1,2008.Published November 2008.Originallyapproved in 1998.Last previous edition approved in 2002 as E1945 02.DOI:10.1520/E1945-02R08.2For 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 Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For Suggestions on the testing of reagents notlisted by the American Chemical Society,see Annual Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 flask.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 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).Transfer 2.50 mL of synthetichard water stock by pipet to a 1000-mL volumetric flask anddilute to volume with water at 20C.Mix solution thoroughly.NOTE2It 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 D112