1、Designation: D3448 10Standard Test Method forSpecific Aqueous Conductance of Trichlorotrifluoroethane1This standard is issued under the fixed designation D3448; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. 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 covers the determination of aqueousconductivity due to ionizable contaminants extracted fromtrichlorotrifluoroe
3、thane. The value of 1.9 S/cm as maximumspecific aqueous conductance corresponds to 0.1 ppm ofchloride ion (100 ppb). It was calculated by putting the solventspecification of 0.1 ppm chloride into the equation of thesubject method to find C2 C1equals 19.08. The specificconductance due to contaminants
4、 from the solvent was thencalculated as follows:C22 C1!C35 19! 0.1! 5 1.9 S/cm (1)1.2 The above is exclusive of the background specificconductance of the water used in the analysis.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstan
5、dard.1.4 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 consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.
6、Specific precautionary statements are given in Section 6.2. Summary of Test Method2.1 Ionizable impurities in the solvent are extracted withwater of known low conductivity. The increase in waterconductivity measures the amount of these impurities present.3. Significance and Use3.1 This test method a
7、llows for the determination of ioniz-able contaminants (expressed in terms of ppb of HCl) intrichlorotrifluoroethane via measurement of specific aqueousconductance.3.2 This test method can be used for establishing manufac-turing and purchasing specifications.4. Apparatus4.1 Conductivity Bridge.24.2
8、Conductivity Cell,3dip-type. Cell constant of 0.1 recip-rocal centimetre. Electrodes must be bright platinum.4.3 Polyethylene Beaker, 250-mL.4.4 Polyethylene Bottles, wide mouth, 300-mL and 500-mLsize.4.4.1 Calibrate and mark the outside of the 300-mL poly-ethylene bottles to indicate 20, 120, and 2
9、20 mL (graduate) ofwater volume, using deionized water to determine the liquidlevels.4.5 Polyethylene Tubing, long enough to reach the bottomof the 300-mL polyethylene bottle.5. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intende
10、d thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without
11、 lessening theaccuracy of the determination.1This test method is under the jurisdiction of ASTM Committee D26 onHalogenated Organic Solvents and Fire Extinguishing Agents and is the directresponsibility of Subcommittee D26.04 on Test Methods.Current edition approved June 1, 2010. Published August 20
12、10. Originallyapproved in 1975. Last previous edition approved in 2005 as D3448 85(2005).DOI: 10.1520/D3448-10.2The sole source of supply of the apparatus (Serfass Model RCM-15B1) knownto the committee at this time is Industrial Instrument Inc., Cedar Grove, NJ. If youare aware of alternative suppli
13、ers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.3The sole source of supply of the apparatus (Model Cel-A01) known to thecommittee at this time is Industri
14、al Instrument Inc., Cedar Grove, NJ. If you areaware of alternative suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1which you may attend.4Reagent Chemicals, American C
15、hemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S
16、. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Alcoholic Hydrochloric Acid (0.01 N)Dilute 5.0 mL(pipet) of concentrated hydrochloric acid to 6 L with denatured2B ethyl alcoho
17、l.5.3 Alumina Gel.55.4 Deionized Trichloromonofluoromethane, in 25-kg cylin-der. This deionized solvent may be selected pure material or itmay be purified by multiple passes through an alumina gelcontactor (see Fig. 1). Check the acceptability of this deionizedsolvent as described in 7.4.NOTE 1The u
18、se of deionized trichloromonofluoromethane will serveas a check on the cleanliness. The deionized standard should be used asrequired on a periodic basis when samples are being evaluated. Standardsshould be checked whenever high values are obtained or there is doubt ofthe results.5.5 Deionized WaterD
19、istilled water passed through twomixed resin ion exchangers connected in series and having aconductance of no greater than 0.5 S. Check the acceptabilityof the deionized water in accordance with 7.3.5.6 Ethyl Alcohol.NOTE 2Specially denatured ethyl alcohol conforming to FormulaSD-2B of the U.S. Bure
20、au of Internal Revenue may be substituted forethyl alcohol (95 %).5.7 Hydrochloric Acid, concentrated.5.8 Ion-Exchange Cylinders.66. Safety Precautions6.1 Both trichlorotrifluoroethane and trichloromonofluoro-methane are not flammable and have threshold limit values of1000 ppm by volume in air. The
21、respective boiling points ofthese solvents are 47.6 and 23.7C.Avoid repeated skin contactwith the solvents. They remove surface oils from skin.6.2 Denatured ethyl alcohol is flammable and has a thresh-old limit value of 1000 ppm by volume in air.6.3 Hydrochloric AcidTake all precautions necessary to
22、avoid contact with the body internally and externally. The acidis corrosive.7. Procedure7.1 The basis of this test method is the determination byconductance of ions present in the test solution. Therefore,clean all equipment carefully to remove all adsorbed ions in themeasuring apparatus, otherwise,
23、 erroneously high values willbe obtained. Do the initial cleaning and the cleaning ofequipment in accordance with 7.2. All equipment must berinsed with deionized trichloromonofluoromethane before us-ing in a test.7.2 Deionizing of Equipment:7.2.1 Polyethylene Bottles and Stainless Steel Cylinders:7.
24、2.1.1 Add about 30 g of ion exchange resin from anexchange cylinder to the item to be cleaned. Use an exchangecylinder as a source of resin for cleaning.7.2.1.2 Add deionized water to the container until it is abouttwo-thirds full.7.2.1.3 Close the container and roll for at least 24 h on a ballmill
25、roller or its equivalent.7.2.1.4 Discard the ion-exchange resin and water, rinse withdeionized water and then with deionized trichloromono-fluoromethane.7.2.2 Polyethylene Delivery Tubes:NOTE 3Use of highly plasticized polyethylene tubing and bottles isnot recommended.7.2.2.1 Place the polyethylene
26、delivery tubes in a 500-mLpolyethylene bottle.7.2.2.2 Clean by following 7.2.1.1-7.2.1.4.7.2.3 Polyethylene Beakers, Dip-Cell, and Other Equip-ment:7.2.3.1 Add about 30 g of ion-exchange resin to the beaker.7.2.3.2 Fill the beaker with deionized water.7.2.3.3 Stir, shake, or transfer the mixture fro
27、m one con-tainer to another for at least 2 min.7.2.3.4 Discard the ion-exchange resin and deionized watermixture.5The sole source of supply of the apparatus (Grade F-3) known to the committeeat this time is Aluminum Company of America. If you are aware of alternativesuppliers, please provide this in
28、formation to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.6The sole source of supply of the apparatus (Illco-Way ion exchange cylinders,research model) known to the committee at this time is
29、Illinois Water Treatment Co.,Rockford, IL. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.FIG. 1 Alumina Gel Contrac
30、torD3448 1027.2.3.5 Rinse the equipment with deionized water and thenwith deionized trichloromonofluoromethane before using in atest.7.3 Preparation of Deionized Water:7.3.1 Slowly pass distilled water through two mixed resinion exchangers, in series, immediately before use, into a clean250-mL polye
31、thylene beaker. (Note 4). Do not deionize waterand store, since it will adsorb carbon dioxide.NOTE 4If the conductance of the water is greater than 0.5 S, repeatthe treatment and testing of the water until 0.5 S or less is obtained,replace the resin exchanger and clean the equipment as described ina
32、ccordance with 7.2.7.3.2 Measure the conductivity of the water by the conduc-tivity bridge. Conductance of the water should not be greaterthan 0.5 S when measured by a dip-type conductance cellhaving bright platinum electrodes and a cell constant of 0.1 S.NOTE 5The beaker of water used to store the
33、conductance dip-cellshould contain deionized water. This water will gradually adsorb carbondioxide, etc. from the air and the conductivity will increase. In order toprevent errors from cell contamination and as long as the apparatus is inconstant use, this water should be removed whenever its conduc
34、tivityexceeds 1.0 S. During startup, the cell should be dipped in freshlydeionized water often enough to remove accumulated ions.7.4 Testing of Deionized TrichloromonofluoromethaneThe deionized trichloromonofluoromethane is used to providea vapor blank to exclude carbon dioxide and other contamina-t
35、ion during the analysis.7.4.1 Add the selected trichloromonofluoromethane to thepolyethylene bottle by filling to the 20-mL calibration mark onthe bottle. Add the solvent directly from the inverted cylinderwithout use of any fittings except a cylinder adapter.7.4.2 Cap the bottle and shake well.7.4.
36、3 Discard the solvent.7.4.4 Add another 20 mL of the selected solvent to thebottle.7.4.5 Immediately add 100 mL of deionized water by fillingto the 120-mL calibration mark on the bottle.7.4.6 Cap the bottle tightly and shake well for 2 min.7.4.7 Open the bottle and insert the dip-cell of the conduc-
37、tivity bridge into the water layer.7.4.8 Measure and record conductivity value as the blankconductance.7.4.9 Remove the dip-cell and place it in a polyethylenebeaker of deionized water (see Note 3).7.4.10 Recap the polyethylene bottle loosely, leaving thesolvent and water in the bottle.7.4.11 Connec
38、t a polyethylene delivery tube to the cylinderof selected solvent.7.4.12 Slowly open the cylinder valve to flush the deliverytube.7.4.13 Remove the cap from the bottle (7.4.10) and insertthe delivery tube so that the tip is below the water level, nearthe bottom of the bottle.7.4.14 Add100mLofselecte
39、dsolvent(trichloromonofluoro-methane) in this manner, filling to the 220-mLcalibration markon the bottle. One hundred millilitre of this solvent is equiva-lent to 150 g.7.4.15 Remove the delivery tube and cap the bottle.7.4.16 Shake the bottle for 2 min, remove the cap, andmeasure the conductance of
40、 the water layer as the secondconductance.7.4.17 Subtract the blank conductance from the secondconductance. If a value greater than 0.5 S/100 mLis obtained,repeat until the value is constant. If a constant value greaterthan 0.5 S/100 mL is obtained, the selected trichloro-monofluoromethane is not ac
41、ceptable (see Note 5). The solventfound acceptable will be referred to as deionized trichlo-romonofluoromethane.NOTE 6If a test cylinder has a high conductance value, it willcontaminate the equipment. A series of washes with trichloromonofluo-romethane of low conductance value will be needed to remo
42、ve thecontamination. The operation is a self-cleaning one, repeated testing oflow conductance value solvent will assist in cleaning up of the equipment.7.5 Analysis of Trichlorotrifluoroethane:7.5.1 Determine the blank conductance of the deionizedwater and deionized trichloromonofluoromethane as des
43、cribedin 7.4.1-7.4.10.7.5.2 Tare weigh the polyethylene bottle containing thedeionized water and deionized trichloromonofluoromethane tothe nearest 0.1 g.7.5.3 Weigh 150 6 1 g of trichlorotrifluoroethane to thenearest 0.1 g, into the bottle. A volume sample equivalent to150 6 1 g may be used instead
44、 of a weighed sample.7.5.4 Recap the bottle tightly and shake it for 2 min.7.5.5 Open the bottle and measure and record the conduc-tivity value of the water layer as the second conductance.7.5.6 Loosely cap the bottle. The trichloromonofluorometh-ane left in the bottle serves to protect the interior
45、 fromatmospheric contamination. It should be left in the bottle until a new sample is to be tested at which time it is discarded.8. Calculation8.1 Calculate the amount of ionizable contaminants intrichlorotrifluoroethane in terms of ppb of HCl as follows:C22 C1! 3 C33 52.4 5 ppb of soluble ionizable
46、 materialcalculated as HCl. This value canbe expressed in ppm of HCl orppm of chloride. (2)where:C2= second conductance value (dial reading 3 multiplierswitch setting, measurement of deionized water,deionized trichloromonofluoromethane and sample),C1= blank conductance value (dial reading 3 multipli
47、erswitch setting; measurement of deionized water anddeionized trichloromonofluoromethane),C3= cell constant in reciprocal centimetres, and52.4 = ppb HCl/S7,89. Precision and Bias9.1 The precision and bias are estimated to be about 60.02S/cm.7Lingane, J.J., Electroanalitical Chemistry, Interscience P
48、ub., Inc., New York,NY, 19538Berl, W.G., Physical Methods in Chemical Analysis, Vol 11, Academic Press,125 E. 23rd St., New York, NY, 1951.D3448 1039.2 Repeatability and reproducibility studies are planned.10. Keywords10.1 aqueous conductance; conductanceAPPENDIX(Nonmandatory Information)X1. CALIBRA
49、TION OF 52.4 PPB HCl/SX1.1 The factor is a theoretical value and can be calculatedfrom data given in Footnotes 10 and 11. The value can beobtained experimentally as follows:X1.1.1 Determine the blank conductance of the deionizedwater and deionized trichloromonofluoromethane in accor-dance with 7.4.1-7.4.15.X1.1.2 Add 0.010 mL of 0.01 N alcoholic HCl by syringeinto the bottle.X1.1.3 Cap the bottle and shake it for 2 min.X1.1.4 Measure and record the conductance value of thewater layer as the second conductance.X1.2 Calculations:A/W 5 24 ppb HCl in 100 mL
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