Document LpyNB76LJZbpnqLzdky2rEoQz

Study Title Solubility of Perfluoro-1-octanesulfonyl Fluoride (P O S F) in W ater Data Requirement 40 CFR 160.105(b) Author Mark E. Ellefson Performing Laboratory 3M Environmental Laboratory Building 2-3E-09 935 Bush Avenue St. Paul, MN 55106 Project Identification 3M Environmental Laboratory Study # LIMS E01-0859 Total Number of Pages 19 BACK TO MAIN 3M Environmental Laboratory Table of Contents Study Information................................................................................................................................ 4 Summary.......... ............................................... 5 Purpose........................................................................................................... 5 Test Substance........................................................................................ 5 Test System........................................................................................................................................ 6 Method Summaries............................................................................................................................. 6 Preparatory Methods........................................................................................................................... 6 Data Summary.............................................. 7 Statistical Methods and Calculations.................................................................................................. 7 Statement of Conclusion..................................................................................................................... 7 . References.......................................................................................................................................... 7 List of Attachments.............................................................................................................................. 8 Signature Page............................... 9 Vt Page 2 of 19 BACK TO MAIN 3M Environmental Laboratory List of Tables Table 1. Summary Table of Solubility of POSF TN-A-2825 in Water................................................. 5 Table 2. Characterization of the Test Substance..............................................................................5 Table 3. Description of test systems used in this study....................................................................6 Table 4. Summary of Sample Preparation.........................................................................................7 Table 5. Summary Table of Solubility of POSF TN-A-2825 in Water................................................. 7 4i Page 3 of 19 Study Information Analytical Chemistry Laboratories Solubility Testing 3M Environmental Technology and Safety Services (ET&SS) 3M Environmental Laboratory Bldg. 2-3E-09 935 Bush Avenue St. Paul, MN 55106 Dr. William K. Reagen, Laboratory Manager Mark E. Ellefson, Principal Analytical Investigator Kristin L. Terrell, Analytical Chemist Mark L. Anderson, Analytical Chemist Experimental Dates ' Sample Analysis Initiation: 24 May 2001 Sample Analysis Completion: 01 Jun 2001 /t BACK TO MAIN 3M Environmental Laboratory Page 4 of 19 BACK TO MAIN 3M Environmental Laboratory Summary Solubility of Perfluoro-1-octanesulfonyl fluoride (POSF) in water is a significant parameter because the spatial and temporal movement (mobility) of a substance through the environment is largely determined by its solubility in water. Water soluble substances readily gain access to humans and other living organisms; furthermore the knowledge of the solubility in water is a prerequisite for testing biological degradation, bioaccumulation, and other tests. The approximate solubility of POSF was determined by performing a solubility screen test (ETS-8-170.1). POSF was determined to be soluble at concentrations less than 294 qg/mL in water at 22-24C. Results are presented in table 1: Table 1. Summary Table of Solubility of POSF TN-A-2825 in Water. S olvent POSF S o l u b il it y Water < 294 ng/m L I The solubility of POSF was determined to be less than 294 qg/mL in water at 22-24'C. Purpose The purpose of this study was to determine the solubility of POSF in water. Test Substance Perfluoro-1-octanesulfonyl fluoride (POSF), TN-A-2825 Table 2. Characterization ofthe Test Substance Test Substance Source Expiration Date Storage Conditions 3M Laboratory Identification Number Physical Description Purity POSF Aldrich 01-01-2010 Ambient TN-A-2825 Clear liquid, density = 1,824g/mL 98% Page 5 of 19 BACK TO MAIN 3M Environmental Laboratory Test System Table 3. Description of test systems used In this study Source Expiration Date Storage Conditions 3M Laboratory Identification Number Purity/Grade W ater Millipore System NA Ambient NA ASTM Type I Method Summaries The solubility determination of POSF TN-A-2825 in water was performed according to 3M Laboratory Method ETS-8-170.1 "Solubility Screen Test: Approximate Solubility Determination of a Test Substance in Various Solvents". V: The Solubility Screen Test Method was used to determine the solubility range of POSF TN-A2825 in water. Incremental amounts of water were added to POSF neat material and a qualitative determination of the solubility was made. The screen test indicated the solubility of POF to be less than 294 qg/mL in water at 22-24`C. A detailed description of the Solubility Screen Test method used in this study is located in Attachment A. Preparatory Methods ETS-8-170.0 "Solubility Screen Test: Approximate Solubility Determination of a Test Substance in Various Solvents." This method is a pre-requisite to the shake flask and column elution methods and provides an estimate of the solubility of the test substance in the solvent of choice. Microliter amounts of sample were added to varying amounts of water. Following sample addition, the volumetric flasks were shaken and observed for POSF droplets on the bottom. The solubility screen test estimated the solubility of POSF to be less than 294 qg/mL in water at 22-24C. Page 6 of 19 BACK TO MAIN 3M Environmental Laboratory Table 4. Summary of Sample Preparation. S tep S a m p l e P r e p a r a t io n D a t e (s ) P erfo rm ed 1 10 uL test substance is added to 4.203L (4.33mg/L) of water in a 4 L 5/24/01 volumetric flask. 2 The volumetric flask is sealed, shaken and then allowed to sit over night 5/24/01 for 24 hours. 3 The volumetric flask is visually checked for the test substance, which 5/25/01 would be in the form of oily droplets on the bottom. 4 This same test was done with 5uL in 6.205L (1.47ug/mL) and 1uL in 5/25/01 to 6/01/01 6.205L (294ng/mL) in a 6 L volumetricflask. The 294ng/mL solution was allowed to sit for 5 days. The sample was still visible in the flask after 5 days. Data Summary Table 5. Summary Table of Solubility of POSF TN-A-2825 inWater. S olvent POSF S o l u b il it y J W ater < 294 q g /m L The solubility of POSF, TN-A-2825 in water is less than 294 qg/mL at 22-24"C. Statistical Methods and Calculations No statistical methods or calculations were required. The data was reported as the solubility of POSF being less than 294 qg/mL at 22-24"C in water as determined by the initial screening method. . Statement of Conclusion Under the conditions of the present study, the solubility of POSF TN-A-2825 in ASTM Type I water is less than 294 qg/mL at 22-24 C. References 1. Fate, Transport and Transformation Test Guidelines Office of Prevention, Pesticides and Toxic Substances (OPPTS) 830.7840 Water Solubility: Column Elution Method; Shake Flask Method. EPA 712-C-96-041, August 1996. 2. OECD 105: Water Solubility. Adopted 27July, 1995. Page 7 of 19 BACK TO MAIN 3M Environmental Laboratory List of Attachments Attachment A: Solubility Screening Method ETS-8-170 "Solubility Screen Test: Approximate Solubility Determination of a Test Substance in Various Solvents", including the sample preparation worksheets. Page 8 of 19 BACK TO MAIN 3M Environmental Laboratory Signature Page We certify that this report is a true and complete representation of the data for this phase of the study: Mark E. Ellefson Principal Analytical Investigator William K. Reagen Laboratory Manager -------- Date Page 9 of 19 Attachment A BACK TO MAIN 3M Environmental Laboratory i Page 10 of 19 3M Environmental Laboratory BACK TO MAIN 3M Environmental Laboratory Solubility Screen Test: A pproximate Solubility Determination of a Test Substance in Various Solvents Method Number: ETS-8-170.1 Adoption Date: 09/08/00 Effective Date: 03/14/01 Approved By: 1.0 Scope and Application_______________________ ;___________________________________ 1.1 Purpose. According to methods set forth by the United States Environmental Protection Agency (US EPA) and the Organization for the Economic Cooperation and Development (OECD) a preliminary study, which will be outlined in this method, serves as a prerequisite to performing solubility testing via the Column Elution Method and Shake Flask Methods. The EPA and OECD solubility testing guidelines state that if the preliminary solubility determination test indicates a solubility of > 10'2g/L (10 ppm), the Shake Flask Method (ETS-8-172.0) is to be used. If preliminary testing indicates a solubility of < 10`2g/L (10 ppm) the Column Elution Method (ETS-8-171.0) will be used to determine the solubility in the solvent of interest. Additionally, due to the tendency of certain compounds to be highly soluble in particular solvents, no further solubility determination will be necessary for compounds having solubility greater than 10% (mass/volume). 1.2 Compatible Analytes. Test substance and degradation products for solubility testing. ETS-8-170.1 Solubility Determination: Screen Test Method Page 1 of 9 Page 11 of 19 BACK TO MAIN 3M Environmental Laboratory 1.3 Acceptable Matrices. Aqueous (e.g. Milli-Q water, 0.01M CaCl2), Acetone, Methanol, or other solvent(s) of interest. 2.0 Summary of Method_____________________________________________________ 2.1 Preliminary Solubility Determination in solvent. Weigh approximately 10 mg of test substance into a 2.5 mL-4 mL glass screw-capped vial. Add test solvent in varying increments to the vial. After each solvent addition, vortex mix for approximately 15 sec., and sonicate 2-5 minutes. Make observations of the solution and visually confirm whether or not particles are present; it may be necessary to allow the solution to sit for up to 5 minutes. Add test solvent in a stepwise fashion up to 2 mL. If the substance fully dissolves after the first solvent addition of 100 pL, the test substance shall be considered highly soluble, and no further testing is required. If there are still undissolved particles in the vial, weigh 10 mg of test substance into a 100 mL glass stoppered volumetric flask or graduated cylinder. Add test solvent until visual confirmation of the substance dissolution has been achieved. Record all observations on a standardized preparation sheet or logbook. Once 100 mL solvent has been reached, the approximate concentration is at 100 pg/mL. If the solubility limit has not yet been achieved, weigh approximately 10 mg of test substance and transfer to a 1 L graduated cylinder/volumetric flask (concentration is approximately 10 ppm). The container should be sonicated and allowed to sit overnight to allow for maximal dissolution. If the undissolved particles are still observed after sitting > 12 hours, the column elution method will be utilized (ETS-8-171.0). If the test substance dissolves in 1 L or less of solvent, the shake flask method (ETS-8-172.0) will be used to ' determine the solubility. 3.0 Definitions_____________________________________________________ .____________ 3.1 Test substance. A liquid or solid material for which the relative solubility in a specified solvent will be determined. 3.2 Test solvent. The matrix to which the test substance of interest is introduced. The test solvent may include but is not limited to aqueous matrices, including ASTM Type I Water and various salt matrices (e.g. 0.01M CaCl2(aq)); and organic solvent matrices, including methanol, and acetone. 4.0 Warnings and Cautions_________________________________________________________ 4.1 Health and Safety Warnings: 4.1.1 Wear the proper lab attire for all parts of these procedures. Wear gloves and eye protection at all times. 4.1.2 Handle all solvents in a hood for all parts of the described sample preparation procedure. 4.1.3 For potential hazards of each chemical used, refer to material safety data sheets, packing materials, and 3M Environmental Laboratory's Chemical Hazard Review. 4.1.4 No mouth pipetting is allowed. ETS-8-170.1 Solubility Determination: Screen Test Method Page 2 of 9 Page 12 of 19 BACK TO MAIN 3M Environmental Laboratory 4.2 Cautions: 4.2.1 Glassware in which standards are prepared should be triple rinsed with acetone and methanol to reduce the possibility of accidental contamination. 5.0 Interferences_________________________________________________________________ 5.1 Impurities may significantly affect the solubility of the test substance. The purity of the test substance should be known and documented prior to starting the screening procedure. 6.0 Equipment______________________________________________________________________ 6.1 Analytical balance sensitive to 0.1 mg. 6.2 Vortex mixer. 6.3 Sonicating device. 7.0 Supplies and Materials________________________________________________________ 7.1 Disposable glass graduated pipettes, 1 mL to 100 mL. 7.2 Disposable glass Pasteur pipettes and rubber bulbs. 7.3 Glass beakers, various sizes. 7.4 2.5 mL-4 mL glass screw-top vial. 7.5 Glass volumetric flasks, 10 mL to 1000 mL. 7.6 10 p.L-1000 pL PipettemanTM manual pipettor and plastic pipette tips, or equivalent. 8.0 Reagents and Standards_______________________________________________________ 8.1 Methanol (MeOH), HPLC/SPEC/GC grade from EM Science, or equivalent. 8.2 Acetone, HPLC/SPEC/GC grade from EM Science or equivalent. 8.3 Water, ASTM Type I, or equivalent. 8.4 Calcium Chloride Dihydrate, Approximately 99% or better, from Sigma or equivalent. 8.5 0.01 M CaCl2, A 0.01 M CaCl2stock solution is prepared by weighing 1.5 g CaCl2 Dihydrate in a weigh boat and transferring to a 1 L volumetric flask and diluting to the mark with Milli-QTM water. 8.6 Test substance of known purity. 9.0 Sample Handling_________________________________^______________________________ 9.1 Record times of initial preparation and dilution on a sample preparation sheet or logbook. 9.2 Once the preliminary testing has been completed and the appropriate information is extracted, the screen test samples should be disposed into the proper waste stream. ETS-8-170.1 Solubility Determination: Screen Test Method Page 3 of 9 Page 13 of 19 BACK TO MAIN 3M Environmental Laboratory 10.0 Quality Control__________________________________________________________ ___ 10.1 Not applicable. 11.0 Calibration and Standardization_____________________________________________ 11.1 The compounds of interest must be of known characterization according to laboratory specifications. 11.2 All equipment used, such as the analytical balance, should be calibrated daily prior to use. 12.0 Procedures___________________________________________________________________ 12.1 Solubility screen. 12.1.1 Weigh 10 mg 1 mg of test substance into a 4 mL glass screw-top vial or equivalent. Record the weight (refer to attachment A for an example of a standardized prep sheet). 12.1.2 Add solvent (e.g. water, methanol, acetone) according to the table below to the test substance. 4 mL vial or equivalent Total volume solvent added (mL)... Approximate Solubility (pg/mL)... Solvent addition 1 0.1 100000 Solvent addition 2 0.5 20000 Solvent Solvent addition 3 addition 4 12 10000 5000 12.1.3 Following addition of solvent, vortex mix approximately 15 seconds, sonicate 2-5 minutes. Visually check for undissolved particles. If undissolved test substance remains, continue adding solvent according to the above chart. It may be necessary to allow the solution to settle for up to 5 minutes before making observations. Record observations on the standardized prep sheet. 12.1.4 If all particles dissolve, then estimate the approximate solubility and document the concentration. Because the concentration is >10 pg/mL, the shake flask method (ETS-8-172.0) will be used to determine the accurate solubility point. However, if the test substance dissolves after thefirst solvent addition of 100 pL the solubility is determined to be >10% (mass/volume). The test substance shall be regarded as "highly soluble," and no further testing is required. 12.1.5 If the test substance did not dissolve in the 2 mL of solvent, weigh 10 mg 1 mg of test substance into a 100 mL glass volumetric flask or equivalent. Record the weight (refer to attachment A for an example of a standardized prep sheet). 12.1.6 Add solvent according to the table below to the test substance to deliver the appropriate amount of solvent. As described in 12.1.3, vortex mix, sonicate, and allow the test solution to settle. Record all observations and procedures on the preparation sheet. ETS-8-170.1 Solubility Determination: Screen Test Method Page 4 of 9 Page 14 of 19 BACK TO MAIN 3M Environmental Laboratory 100 m L volum etric Solvent addition 1 Solvent addition 2 Solvent addition 3 flask or equivalent Total volume solvent 10 50 100 added (mL)... Approximate Solubility (pg/mL)... 1000 200 100 12.1.7 If the solubility point is reached at or prior to the complete addition of 100 mL, the concentration estimation at which the substance is soluble should be documented and shall be used as a starting point for the shake flask method (ETS-8-172.0). 12.1.8 If the 100 mL solvent level has been reached without complete dissolution of test substance, weigh out 10 mg 1 mg test substance and transfer to a 1 L volumetric . flask, graduated cylinder, or equivalent. Dilute to 1 L with test solvent. The approximate concentration of test substance is at 10 pg/mL. The flask should be allowed to sit 12-24 hours to allow for maximal dissolution. If the undissolved particles are still observed, the column elution method will be utilized (ETS-8171.0) . If no visible particulates are observed, the shake flask method (ETS-8172.0) shall be used to determine the solubility. 13.0 Data Analysis and Calculations___________________________________________ __ 13.1 The solubility determination in this method is qualitative/semi-quantitative. _ 13.2 The point to which the substance dissolves in solvent is confirmed visually. The solubility point is therefore a qualitative determination. 13.3 The concentration estimation is semi-quantitative in that the approximate concentration is calculated by the following equation: c = a/b Where: c= the semi-quantitative concentration pg/mL, a= amount of substance weighed out (pg), and b= the approximate amount of solvent added (mL). 14.0 M ethod Performance_________________________________________________________ 14.1 Limitation of data. The accuracy to which the solubility is determined is subject to a large margin of error due to the way in which the solvent is added to the solute. Since large and varying increments of solvent are being added to the solute, this error margin must be considered when reporting the concentration estimation. 14.2 The data obtained through this study is an estimation only and should be treated as a qualitative estimation of the solubility of test substance in a given solvent. ETS-8-170.1 Solubility Determination: Screen Test Method Page 5 of 9 Page 15 of 19 BACK TO MAIN 3M Environmental Laboratory 14.3 For an accurate measurement of the substance solubility concentration, the shake flask method, or column elution method will be used. 15.0 Pollution Prevention and Waste Management_____________________________ __ 15.1 Dispose of sample waste by placing in high or low BTU containers as appropriate. Use broken glass containers to dispose of glass pipettes. 16.0 Records_________________________________________________________ _ 16.1 Sign and date all observations and calculations. 17.0 Attachments__________________________________________________________________ 17.1 Attachment A-Example of a Standardized Sample Preparation Sheet: Solubility Screen Prep Sheet. 18.0 References____________________________________________________________________ 18.1 Organization for Economic Cooperation and Development. OECD Guideline for Testing of Chemicals. Water Solubility -OECD Guideline 105: pp. 1-7, Adopted 1995 18.2 United States Environmental Protection Agency. OPPTS 830.7860 Water Solubility (Generator Column Method). Prevention, Pesticides and Toxic Substances: Fate, Transport .and Transformation Test Guidelines. EPA 712-C-96-042: pp. 1-17,1996 18.3 United States Environmental Protection Agency. OPPTS 830.7840 Water Solubility: Coliimn Elution Method; Shake Flask Method. Prevention, Pesticides and Toxic Substances: Fate, Transport and Transformation Test Guidelines. EPA 712-C-96-041: pp. 1-12, 1996 18.4 3M Environmental Laboratory Method ETS-8-171.0, "Column Elution Method: Solubility Determination of Test Substance in Various Solvents." 18.5 3M Environmental Laboratory Method ETS-8-172.0, "Shake Flask Method: Solubility Determination of Test Substance in Various Solvents." 19.0 Affected Documents_______________________________________________________ 19.1 ETS-8-171.0, "Column Elution Method: Solubility Determination of Test Substance in Various Solvents." 19.2 ETS-8-172.0, "Shake Flask Method: Solubility Determination of Test Substance in Various Solvents." ETS-8-170.1 Solubility Determination: Screen Test Method Page 6 of 9 Page 16 of 19 BACK TO MAIN 3M Environmental Laboratory 20.0 R evisions______________________________________________________________________ Revision Number Reason For Revision Revision Date 1 It was desirable to make the method more universally applicable by removing references to specific test substances. 03/13/01 ETS-8-170.1 Solubility Determination: Screen Test Method Page 7 of 9 Page 17 of 19 Attachment A: Example Preparation Worksheet, page 1 o f 2 BACK TO MAIN GLP Study Number: Test Substance: SM Fnvirnnmental l aboratory SOLUBILITY SCRf-FN ItMfc------ ------ Sample preparation worksheet V Date: Source: Solvent: ID#: Step Source: 1 Weigh approximately 1 0 mg 1 mg of test substance into a 2.5 mL-4 mL glass screw-top vial. Weight of test substance: ----------------- mg Balance ID:-------------------- Date/lnitials: 2nd replicate optional:_ _mg Thermometer ID: 2 Add test solvent according to the table below. Following each addition o f solvent, shake vigorously/vortex, and sonicate the mixture and visually check for undissolved particles. Analyst Analyst Analyst Analyst volume added (mL)/ approx cone, after addition (ug/mL) Sample Prep D ate /T im e .. _/_ Step 2-1 Total volume solvent added (mL) Q.1 Approximate Solubility (ug/mL) 100,000 Flask vortex-mixed? Yes/No Room T e m p Flask sonicated? Yes/N o Time------------Flask allowed to settle? Yes/N o Time__ D ate/T im e- Step 2-2 Total volume solvent added (mL) Q.5 20.000 D ate /T im e - Step 2-3 1Total volume solvent added (mL) Approximate Solubility fug/mU .10.000 Date/Time_ Step 2-4 Total volume solvent added (mL) 2 Approximate Solubility (ug/mL) 5.000 Flask vortex-mixed? Yes/N o R o o m T e m p Flask sonicated? Yes/N o Time-------------Flask allowed to settle? Yes/N o Time-- Flask vortex-mixed? Yes/No Room Te m p Flask sonicated? Yes/N o Time------------Flask allowed to settle? Yes/N o Time-- Flask vortex-mixed? Yes/N o Room Tem p Flask sonicated? Yes/No Time________ Flask allowed to settle? Y es/N o Time___ OBSERVATIONS/NOTES Is there solute still presentYes-continue to step 2-2 N O - The solution is at 10%, and is considered "infinitely soluble." further solubility testing is required. Is there solute still present? Yes/No Is there solute still present? Yes/No Is there solute still present? Yes/No Conclusions: Did the substance dissolve in 2 mL or less o f solvent? Yes -Approximate concentration at which the test substance is soluble in solvent:_______ng/ml The solubility of the test substance is to be determined via the shake flask method, or No Continue to page two for further testing.- Notes/ additional comments: 3M Environmental Laboratory Page 18 of 19 ETS-8-170.1 Solubility Determination: Screen Test Method Page 8 of 9 Attachment A Cotti.: Example Preparation Worksheet, pase 2 o f 2 BACK TO MAIN 3M Environmental Laboratory SOLUBILITY SCREEN G L P S tu d y N u m b e r : _______________________________ Sample preparation worksheet T e s t S u b s ta n c e :_________________________ id * _______________ Source:____________ D ate:_____________ ^ ________ - S o lve n t:_________________________________id* _____________ Source:____________ Step (continued from page 1) ***D id th e te s t substance dissolve in 2 m L? Y es/N o If Y E S , the te s t is co m p lete, and th ere is no need to c o n tin u e w ith th e screen test. If NO , continue to step 3 to determ ine the approxim ate solubility o f the substance. 3 Weigh approximately 10 mg 1 mg of test substance into a 100 mL graduated stoppered cylinder/volumetric flask. Weiqht of test substance: ma Balance ID: . Date/lnitials: 2nd replicate optional: ma Therm om eter ID: . 4 Add test solvent according to the table below. Following each addition o f solvent, shake vigorously/vortex, and sonicate the mixture and visually check for undissolved particles.______________________________________________________________ volume added (m L )l approx cone, after S o lu b ilitv data addition (ug/mL) Sample Prep O B SER VATIO N S/N O TES Analyst Date/Time / Step 4-1 Total volume solvent added (mU... 10 Approximate Solubility (ug/mL)... 1,000 Flask vortex-mixed? Yes/No Room Temp Flask sonicated? Yes/No Time Flask allowed to settle? Yes/No Time C Is there solute still present? Yes/No min min Analyst Date/Time / Step 4-2 Total volume solvent added (mL)... 50 Approximate Solubility (ug/mL)... 200 Flask vortex-mixed? Yes/No Room Temp Flask sonicated? Yes/No Time Flask allowed to settle? Yes/No Time Is there solute still present? Yes/No min min Analyst Date/Time / Step 4-3 Total volume solvent added (mL)... 100 Approximate Solubility (ug/mL)... 100 Flask vortex-mixed? Yes/No Room Temp Flask sonicated? Yes/No Time Flask allowed to settle? Yes/No Time C Is there solute still present? Yes/No min min 5 Weigh approximately 10 mg 0.5 mg o f test substance into a 1 L graduated stoppered cylinder/volumetric flask/or equivalent. W eight of test substance: mg Balance ID: Date/lnitials:. Analyst Date/Time Step 5-1 Total volume solvent added (mL}... 1000 Approximate Solubility (ug/mL)... 10 Flask vortex-mixed? Yes/No Room Temp Flask sonicated? Yes/No Time Flask allowed to settle? Yes/No Time "C Is there solute still present? Yes/No min min C o n c lu s io n s : D id the substance dissolve in 1000 m L o r less o f solvent? Y e s -Approxim ate concentration at which the test substance is soluble in solvent: u a /m l The solubility o f the test substance is to be determined via the shake flask method. or N o -T h e solubility o f the test substance is to be determ ined v ia the column elution method. N otes/ additional com ments: 3M Environmental Laboratory Page 19 of 19 ETS-8-170.1 Solubility Determination: Screen Test Method Page 9 of 9