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A RllG-o^ DETERMINATION OF THE VAPOR PRESSURE OF PFOS USING THE SPINNING ROTOR GAUGE METHOD WILDLIFE INTERNATIONAL LTD. PROJECT NUMBER; 454C-105 OECD Guideline 104 Vapour Pressure Curve U.S. EPA OPPTS 830.7950 Vapor Pressure AUTHORS: Raymond L. Van Hoven, Ph.D. Joel I. Stenzel W illard B. Nixon, Ph.D. STUDY INITIATION DATE; January 12,1999 STUDY COMPLETION DATE: May 5,1999 Submitted to 3M Corporation Environmental Laboratory 935 Bush Avenue 3M Building 2-3E-09 P.O .B ox 33331 S t Paul, Minnesota 55133 Wildlife International ltd. 8598 Commerce Drive Easton, Maryland 21601 (410) 822-8600 Page 1 of 26 000057 Wildlife International Ltd . - 2- PROJECT NO.: 454C-105 GOOD LABORATORY PRA CTICE COM PLIANCE STATEM ENT SPONSOR: 3M Corporation TITLE: Determination o f the Vapor Pressure o f PFOS Using the Spinning Rotor Gauge Method WILDLIFE INTERNATIONAL LTD. PROJECT NUMBER: 454C-I05 STUDY COMPLETION: May 5,1999 This study was conducted in compliance with Good Laboratory Practice Standards as published by the U.S. Environmental Protection Agency in 40 CFR Part 792,17 August 1989; OECD Principles o f Good Laboratory Practice, OCDE/GD (92) 32, Environment Monograph No. 45, Paris 1992; and Japan MAFF, 59 NohSan, Notification No. 3850, Agricultural Production Bureau, 10 August 1984, with the following exceptions: The test and reference substances were not characterized in compliance with Good Laboratory Practices Standards. The stability o f the test substance and reference standards under the conditions at the test site was not tested in compliance with Good Laboratory Practice Standards. i STUDY DIRECTOR: DATE 000058 Wildlife International ltd. -3 - PROJECT NO.: 454C-105 i QUALITY ASSURANCE STATEMENT SPONSOR: 3M Corporation TITLE: Determination o f the Vapor Pressure o f PFOS Using the Spinning Rotor Gauge Method WILDLIFE INTERNATIONAL LTD. PROJECT NUMBER: 454C-105 This study was examined for compliance with Good Laboratory Practice Standards as published by the U.S. Environmental Protection Agency in 40 CFR Part 792, 17 August 1989; OECD Principles o f Good Laboratory Practice, OCDE/GD (92) 32, Environment Monograph No. 45, Paris 1992; and Japan MAFF, 59 NohSan, Notification No. 3850, Agricultural Production Bureau, 10 August 1984. The dates o f all inspections and audits and the dates that any findings were reported to the Study Director and Laboratory Management were as follows: ACTIVITY: Test Substance Preparation and Test Initiation Measurement One Draft Report and Data Final Report DATE CONDUCTED: January 27,1999 January 29, 1999 February 24,1999 May 5,1999 DATE REPORTED TO: STUDYDIRECTOR: MANAGEMENT: January 27,1999 January 29,1999 February 24,1999 May 5,1999 January 27,1999 January 29,1999 February 25,1999 May 5,1999 Lisa T. Drottar Quality Assurance Representative DATE 000059 Wildlife International ltd. -4 - PROJECT NO.: 454C-105 REPORT APPROVAL i SPONSOR: 3M Corporation TITLE: Determination o f the Vapor Pressure o f PFOS Using the Spinning Rotor Gauge Method WILDLIFE INTERNATIONAL LTD. PROJECT NUMBER: 454C-105 STUDY DIRECTOR: MANAGEMENT: W illard B. Nixon, PLD. ' Manager, Analytical Chemistry DATE ' T~ DATE 000060 Wildlife International ltd. p r o j e c t n o .: 454C-105 -5- i TABLE OF CONTENTS Title/Cover Page....................................................................................................................................................... 1 Good Laboratory Practice Compliance Statement................................................................................................. 2 Quality Assurance Statement.................................................................................................................................. 3 Report Approval......................................................................................................................... ...:.........................4 Table o f Contents..... ............................................................................................................................................... 5 Summary................................................................................................................................................................... 7 Introduction.............................................................................................................................................................. 8 O bjective............................................................................................................:.................................................... 8 Experimental Design................................................................................................................................................8 Materials and Methods....................................................... 8 Results and D iscussioa........................................................................................ ...............................................12 Conclusion................................................................................................................................................. References.............................................................................................................................................................. 14 13 TABLES Table 1. Steady-State Pressure o f PFOS Sample.... .................................................................................... 15 Table 2. Pressure Increase o f PFOS Sample........................................................... Table 3. Steady-State Pressure o f Control Sample........................................................................................... 17 Table 4. Pressure Increase o f Control Sam ple.............................................................................................. 18 000061 Wildlife International ltd. 6- - i TABLE OF CONTENTS - Continued - PROJECT NO.: 454C-105 F IG U R E S Figure I. Diagram o f high vacuum system configuration.........................................................:.................... 19 Figure 2. Diagram o f sample introduction system..................................... .................................................... 20 Figure 3. Graphical presentation o f offset measurement................................................................................21 Figure 4. Steady-state pressure and pressure increase o f Hexachlorobenzene sample................................. 22 Figure 5. Steady-state pressure and pressure increase o f DDT sample..........................................................23 Figure 6. Steady-state pressure and pressure increase o f PFOS sample........................................................24 Figure 7. Steady-state pressure and pressure increase o f Control sample......................................................25 A PP E N D IC E S Appendix I. Personnel Involved in the Study................................................................................................ 26 000062 Wildlife International Lm -7 - SPONSOR: SPONSOR'S REPRESENTATIVE: LOCATIONOFSTUDY, RAW DATAANDA COPYOFTHE FINALREPORT: SUMMARY 3M Corporation Ms. Susan A. Beach Wildlife International Ltd. Easton, Maryland 21601 PROJECT NO.: 454C-105 WILDLIFE INTERNATIONAL LTD. PROJECTNUMBER: TEST SUBSTANCE: STUDY: TEST DATES: 454C-105 PFOS (Perfluorooctane Sulfonic Acid, Potassium Salt) Determination o f the Vapor Pressure o f PFOS Using the Spinning Rotor Gauge Method Experimental Start - January 27, 1999 Experimental Termination - February 12,1999 SUMMARY: The vapor pressure o f PFOS was determined to be 3.31 x 1(T*Pa at 20C using the 000063 Wildlife International ltd. 8- - PROJECT NO.: 454C-105 IN T R O D U C T IO N This study was conducted by Wildlife International Ltd. for 3M Corporation at the W ildlife International Ltd. analytical chemistry facility in Easton, Maryland. Tests were performed using the spinning rotor gauge method. The vapor pressure o f the test substance was analyzed from January 27 to February 12,1999. Raw data generated by Wildlife International Ltd. and a copy o f the final report are filed under Project Number 454C-105 in archives located on the Wildlife International Ltd. site. O B JE C T IV E The objective of this study was to determine the vapor pressure of PFOS at 20C using the spinning rotor gauge method. EXPERIM ENTAL DESIGN The spinning rotor gauge (SRG) system was used to determine vapor pressure. The SRG measured the rotational frequency o f a stainless steel ball that was magnetically suspended within a vacuum chamber. The deceleration rate of die ball was used to determine the gas pressure. The system was configured with two sample chambers. One o fthe sample chambers contained a sample o f the test substance, while the other remained empty to make control measurements. The Systran steady-state pressure and pressure increase o f the test substance and control samples were measured three times. MATERIALS AND M ETHODS This study was conducted based on procedures outlined in OECD Guidelines, Method 104 (1); and EPA OPPTS 830.7950 (2). The spinning rotor gauge method was used to determine the vapor pressure o f the test substance. Test Substance The test substance was received from 3M Corporation on October 29, 1998, and was assigned W ildlife International Ltd. identification number 4675 upon receipt. The test substance, a white powder, was identified 000064 Wildlife International ltd. -9 - PROJECT NO.: 454C-105 as: FC-95, Lot 217, 3M ID#: 98-0211-3916-1. Based on information supplied by the Sponsor, the test substance had a purity o f 98.9% and an average molecular weight o f 538 AMU. The test substance was stored under ambient conditions. Reference Substances The hexachlorobenzene reference substance was received from Aldrich Chemical Company on February 10,1997, and was assigned Wildlife International Ltd. identification number 3948 upon receipt. The reference substance, a white powder, was identified as: Hexachlorobenzene; catalog no. 17105-0, CAS Number 118-74-1. The reference substance had a reported purity o f 99%, and was stored under ambient conditions. The DDT reference substance was received from Aldrich Chemical Company on January 20,1999, and was assigned Wildlife International Ltd. identification number 4749 upon receipt. The reference substance, a white powder, was identified as: l,l-bis(p-Chlorophenyl>2,2,2-Trichlaroethane; lot number 77 H3614; catalog no. C8894, CAS Number 50-29-3. The reference substance had a reported purity of 99.3%, and was stored in a refrigerator. Apparatus Configuration The high vacuum system consisted o f a vacuum pump (Leybold TRIVAC S 1,6 B), a turbomolecular pump (Leybold TURBOVAC 50), an ion gauge and controller (Metra 731 Digital Ion Gauge Controller), a spinning rotor gauge (Leybold VISCOVAC VM 212), a sample introduction system, and various stainless-steel con-flat fittings, including three valves. The con-flat fittings were assembled using copper gaskets. The valves were used to isolate the sample chambers, the spinning rotor gauge and/or the vacuum pumps. The spinning rotor gauge controller was connected to a computer via the serial interface (RS-232 port). A diagram o f the apparatus configuration is presented in Figure 1. The sample introduction system was custom designed and manufactured by At-M ar Glass Co. (Kennett Square, PA). The system consisted o f two high vacuum glass sample tubes. During the study, one tube contained a sample o f the test or reference substance while the other tube remained empty (control). The temperature of the samples were maintained by immersing the sample tubes in a water bath. The temperature o f the water bath was periodically monitored using an ASTM 44C mercury thermometer. The tubes were independently vented and connected to the vacuum system using three ground-glass stopcocks. A glass to metal transition flange 000065 Wildlife International ltd. -1 0 - PROJECT NO.: 454C-105 connected the sample introduction system to the vacuum system. A diagram o f the sample introduction system is presented in Figure 2. A steel ball was inserted into the spinning rotor gauge tube before the tube was connected to the high vacuum system. The con-flat fittings and valves o f the high vacuum system were wrapped in heat tape. The temperature o f the heat tape was controlled using a rheostat The surface temperature o f the vacuum system was periodically monitored using an Omega Model HH23 digital thermometer (Omega Engineering, Inc., Stamford, CT) with a thermocouple placed between the heat tape and the outer surface of the fittings. The air temperature also was periodically monitored using the digital thermometer. Procedures The high vacuum system was heated to approximately 80C and evacuated for at least 18 hours prior to making any measurements. After heating, the system was allowed to cool until reaching room tempo-ature. The steel ball inside the spinning rotor gauge tube was suspended in a magnetic field and driven to a rotational frequency o f approximately 415 Hz. The deceleration rate o f the ball was monitored using the spinning rotor gauge. The parameters o f the spinning rotor gauge were set to record a deceleration measurement every 30 seconds based on the molecular weight (28.96 g/mole) and viscosity (18.2 x 10"6Pa-s) o f air. The offset value was determined for each sample tube when the deceleration rate reached a plateau. The offset value (mean deceleration rate) was entered into the spinning rotor gauge controller. A sample o f hexachlorobenzene was placed in one o f the sample chambers, while the other chamber remained empty (control). The parameters o f the spinning rotor gauge were changed to record pressure, in Pascal (Pa), every 30 seconds. This setting was used for all subsequent measurements. The molecular weight parameter was set to 284.78 and viscosity was set to zero. The sample chamber was evacuated to achieve a steady-state pressure. Temperatures were periodically recorded. A fter the system reached temperature and pressure equilibrium, the steady-state pressure o f the sample was measured with the spinning rotor gauge. The valves to the vacuum pumps were then closed, and the pressure increase was monitored for at least two hours. A sample o f DDT was placed in one o f the sample chambers, while the other chamber remained empty (control). The molecular weight parameter was set to 354.5 and viscosity was set to zero. The sample chamber was evacuated to achieve a steady-state pressure. Temperatures were periodically recorded. A fter the system 000066 Wildlife International ltd. - 11- PROJECT NO.: 454C-105 reached temperature and pressure equilibrium, the steady-state pressure o f the sample was measured with the spinning rotor gauge. The valves to the vacuum pumps were then closed, and the pressure increase was monitored for at least two hours. A small sample o f the test substance was placed in one o f the sample chambers, while the other chamber remained empty (control). The molecular weight parameter was set to 538, and viscosity was.set to zero. The sample chamber was opened to the vacuum system and pumped-down to a steady-state pressure. Temperatures were periodically recorded. After the system reached temperature and pressure equilibrium, the steady-state pressure o f the sample was measured with the spinning rotor gauge. The valves to the vacuum pumps were then closed, and the pressure increase was monitored for at least at least two hours. Measurements then alternated between the PFOS sample and the control sample (empty sample chamber) for a total o f three determinations o f each. Calculations The steady-state pressures were determined by averaging the pressure values recorded prior to closing the valves to the vacuum pumps during each measurement Standard deviations and 95% confidence intervals were also calculated. The pressure increase data were analyzed using least-squares-fit linear regression analysis. A line was fit to the portion o f the data that was determined to have achieved equilibrium pressure with the sample. The slope and intercept were calculated for each measurement. Correlation coefficients and 95% confidence intervals for each param eter were also calculated. The out-gassing rate was determined from the slope o f the line and the vapor pressure was determined from the intercept value. The means and standard deviations of the replicate measurements o f the control and PFOS sample were also calculated. 000067 Wildlife International ltd. - 12- RESULTS AND DISCUSSION PROJECT NO.: 454C-105 i A graphical presentation o f the offset measurement is shown in Figure 3. The graphs show data collected for approximately 2 hours from each sample tube. The mean offset value was based on the average deceleration rate measured from left (7.877 x 10"* s'1) and right (6.838 x 10"* s'1) sample chambers on January 6,1999. The offset value was determined to be 7.357 x 1O'* s '1. The steady-state pressure and pressure increase o f hexchlorobenzene were determined on January 14,1999, and are presented in Figure 4. The steady-state pressure was 1.24 x 10'5 Pa and the vapor pressure was determined to be 8.30 x 10"4Pa. The vapor pressure was consistent with the range found in the literature (2). The steady-state pressure and pressure increase o f DDT were determined on January 22, 1999, and are presented in Figure 5. The steady-state pressure was 4.81 x lO-6Pa and the vapor pressure was determined to be 1.76 x 1C4 Pa. The vapor pressure was consistent with the range found in the literature (3). The steady-state pressure and pressure increase o f PFOS were determined on February 3 ,5 and 12,1999. The mean steady-state pressure was 4.51 x 10-6 Pa (Table 1). For each associated pressure increase measurement, the slope o f the pressure increase data became constant after approximately ninety minutes. This indicated the system had achieved saturation o f the gas from the PFOS sample. A line was fit to this region o f the data, and the slope and intercept were determined. The intercept values represented the vapor pressure o f the sample. The mean vapor pressure o f PFOS was 3.31 x 10"4Pa (Table 2). A representative graphical presentation o f the data is shown in Figure 6. The steady-state pressure and pressure increase o f the control sample were determined on February 2 ,4 , and 8,1999. The mean baseline pressure was -1.22 x 1O'6Pa (Table 3). For each measurement, the slope o f the pressure increase data became constant after approximately thirty minutes, indicating the system had achieved equilibrium. A line was fit to this region o f the data, and the slope and intercept were determined. The slope values represented the out-gassing rate o f the system. The mean out-gassing rate was 4.78 x 10'* Pa/sec. (Table 4). The intercept values represented the background pressure o f the system. The mean background pressure was 1.51 x 10'5 Pa. The background pressure was considered insignificant compared to the vapor 000068 Wildlife International lto. -13- PROJECT NO.: 454C-105 pressure o f PFOS and was not subtracted from those values. A representative graphical presentation o f the data is shown in Figure 7. Occasionally during the study, a leak developed at one o f the ground glass joints of the sample introduction system. This was corrected by adjusting the stopcocks and/or repositioning the sample tubes. The spinning rotor gauge displayed either "MTIME TOO LONG" or "BAD SIGNAL" messages during the study, but was restarted without any difficulties each time. The mean temperature o f the water bath, during measurements o f the PFOS sample, was 20.1C and ranged from 19.50 to 20.50C. The air temperature ranged from 19.0 to 22.3 C, and the surface temperature o f the vacuum system ranged from 19.5 to 22.9C. C O N C L U S IO N Based on the results from three sets o f measurements collected from the spinning rotor gauge, the vapor pressure o f PFOS was determined to be 3.31 x 10-4Pa at 20C. 000069 Wildlife International lto. -14- i REFERENCES PROJECT NO.: 454C-105 1 O rganisation for Economic Cooperation and Development 1995. Guideline for Testing o f Chemicals, Method 104, "Vapour Pressure Curve". 2 U.S. Environm ental Protection Agency. 1996. OPPTS 830.7950, Vapor Pressure. Washington, D.C. 3 Tinsley, I.J . 1979. Chemical Concepts in Pollution Behavior. Wiley Interscience, New York. 000070 Wildlife International ltd. -15- PROJECT NO.: 454C-105 Trial Number 1 2 3 Table 1 Steady-State Pressure of PFOS Sample Date 2/3/99 2/5/99 2/12/99 Mean = Std.Dev. = Steady-State Pressure (Pascal) 7.1440 E-6 5.6664 E-6 7.2968 E-7 4.513 E-6 3.359 E-6 Standard Deviation 5.8716 E-7 4.8038 E-7 5.2793 E-7 95% Confidence Interval 6 .1 4 2 6 E -8 6.1158 E-8 6.0657 E-8 000071 Wildlife International ltd. -16- i Table 2 Pressure Increase o f PFOS Sample PROJECT NO.: 454C-105 Trial Number 1 2 3 Slope (Pa/sec.) 95% Confidence Interval 3.5926 E-7 3.5808 to 3.6044 E-7 2.3696 E-7 2.3607 to 2.3785 E-7 1.1970 E-7 1.1949 to 1.1992 E-7 Means 2.386 E-7 StdDev. 1.198 E-7 Intercept (Pascal) 3.2796 E-4 4.6090 E-4 2.0452 E-4 3.311 E-4 1.282 E-4 95% Confidence Interval 3.1615 to 3.3977 E-4 4.5107 to 4.7072 E-4 2.0190 to 2.0715 E-4 Correlation Coefficient 0.99904 0.99875 0.99978 000072 Wildlife International ltd. -17- PROJECT NO.: 454C-105 Trial Number 1 2 3 Table 3 Steady-State Pressure o f Control Sample Date 2/2/99 2/4/99 2/8/99 Mean = Std.Dev. = Baseline Pressure (pascal) -3.4529 E-6 3.1513 E-7 -5.2957 E-7 -1.222 E-6 1.977 E-6 Standard Deviation 5.2286 E-7 4.0515 E-7 1.8258 E-7 95% Confidence Interval 7.3013 E-8 4.1621 E-8 2.2633 E-8 000073 Wildlife International ltd. -18- PROJECT NO.: 454C-105 T a b le 4 Pressure Increase o f Control Sample Trial Number 1 2 3 Means StcLDev. Slope (Pa/sec.) 5.2256 E-8 5.1886E-8 3.9377 E-8 4.7840 E-8 0.7331 E-8 95% Confidence Interval 5.217 to 5.234 E-8 5.186 to 5.191 E-8 3.936 to 3.939 E-8 Intercept (Pascal) 1.9635 E-5 1.7799 E-5 7.8875 E-6 1.5107 E-5 0.6319 E-5 k 95% Confidence Interval 1.917 to 2.010 E-5 1.762 to 1.798 E-5 7.781 to 7.994 E-6 Correlation Coefficient 0.99990 0.99998 0.99999 000074 Wildlife International ltd. - 19- PROJECT NO.: 454C-105 1. vacuum pump 2. turbopump controller 3. sample intro, system 4 . constant temp, water bath 5. spinning rotor gauge head E. turbomolecular pump 7. ion gauge tube 8. ion gauge controller 9. spinning rotor gauge controller 10. personal computer Figure 1. Diagram o f high vacuum system configuratioa 000075 Wildlife International ltd. -20- PROJECT NO.: 454C-105 * glass to metal transition ground-glass stopcocks > sample tubes water bath scissors jack Figure 2. Diagram o f sample introduction system. 000076 Wildlife International ltd. - 21- PROJECT NO.: 454C-105 1.0E-07 9.0E-08 -- Offset Measurements X 8.0E-08 -- (S 7.0E-08 + I 6.0E-08 -- a Right Sample Tube fi.84B-8 5.0E-08 Left Sample Tube 7.88E-8 4.0E-08 H-- -- I-- i--- 1-- I----1-- I---- 1---- 1-- r----i-- l-- i-- I-- I----I-- I -----p 1/6/99 9:00 1/6/99 10:00 1/6/9911:00 1/6/99 12:00 1/6/99 13:00 1/6/99 14:00 Time Figure 3. Graphical presentation o f offset measurement. 000077 Wildlife International ltd. -22- PROJECT NO.: 454C-105 t S teady-S tate P ressu re and P ressure Increase o f H exachlorobenzene Sam ple Figure 4. Steady-state pressure and pressure increase o f Hexachlorobenzene sample. 000078 Wildlife International Ltd. i -23- PROJECT NO.: 454C-105 S teady-S tate P ressure and Pressure Increase o f DDT Sam ple 1/22/99 11:00 1/22/99 12:00 1/22/9913:00 Tim e Figure 5. Steady-state pressure and pressure increase o f DDT sample. 1 /2 2 /9 9 1 4 :0 0 000079 Wildlife International Ltd. -24i PROJECT NO.: 454C-105 S tead y -S tate P ressu re an d P ressure Increase o f P FO S Sam ple 2/3/9 9 1 1 :3 0 2 /3 /9 9 1 2 :3 0 2 /3 /9 9 1 3 :3 0 T im e Figure 6. Steady-state pressure and pressure increase o f PFOS sample. 2 /3 /9 9 1 4 :3 0 000080 Wildlife International ltd. -25- PROJECT NO.: 454C-105 S teady-S tate P ressu re and P ressure Increase o f C o n tro l Sam ple Figure 7. Steady-state pressure and pressure increase o f Control sample. 000031 Wildlife International ltd. -26- PROJECT NO.: 454C-105 APPENDIXI Personnel Involved in the Study The following key Wildlife International Ltd. personnel were involved in the conduct or management of this study: 1. Willard B. Nixon, Ph.D., Manager, Analytical Chemistry 2. Raymond L. VanHoven, Ph.D., Scientist 3. Joel I. Stenzel, B.S., Systems Analyst 4. Keri Leach, B.S., Laboratory Technician 0000S2