1、Designation: D 3448 85 (Reapproved 2005)Standard Test Method forSpecific Aqueous Conductance of Trichlorotrifluoroethane1This standard is issued under the fixed designation D 3448; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 fr
3、omtrichlorotrifluoroethane. 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 specificconductanc
4、e due to contaminants 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 This standard does not purport to address all of thesafety concerns, if any, associated with i
5、ts 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.Specific precautionary statements are given in Section 6.2. Summary of Test Method2.1 Ionizable impurit
6、ies 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 allows for the determination of ioniz-able contaminants (expressed in terms of ppb of HCl) intrichlorotr
7、ifluoroethane 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 Conductivity Cell,3dip-type. Cell constant of 0.1 recip-rocal centimetre. Electrodes must be bright pla
8、tinum.4.3 Polyethylene Beaker,4250-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 220 mL (graduate) ofwater volume, using deionized water to determine the liquidlevels.4.5 Polyethylene T
9、ubing, 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 intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the
10、American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Alcoholic Hydrochloric Acid (0.01 N)Dilute 5.0 mL(pipet
11、) of concentrated hydrochloric acid to 6 L with denatured2B ethyl alcohol.5.3 Alumina Gel.65.4 Deionized Trichloromonofluoromethane, in 50-lb 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 th
12、e acceptability of this deionizedsolvent as described in 7.4.NOTE 1The use of deionized trichloromonofluoromethane will serveas a check on the cleanliness. The deionized standard should be used as1This test method is under the jurisdiction of ASTM Committee D26 onHalogenated Organic Solvents and Fir
13、e Extinguishing Agents and is the directresponsibility of Subcommittee D26.04 on Test Methods.Current edition approved June 1, 2005. Published June 2005. Originallyapproved in 1975. Last previous edition approved in 2000 as D 3448 85(00).2Serfass Model RCM-15B1 has been found satisfactory and can be
14、 obtainedfrom Industrial Instrument Inc., Cedar Grove, NJ. An equivalent may be used.3Model Cel-A01 has been found satisfactory and can be obtained from IndustrialInstrument Inc., Cedar Grove, NJ. An equivalent may be used.4Catalog No. H-4040, Harshaw Scientific Co., Cleveland, OH, has been foundsat
15、isfactory. An equivalent may be used.5Reagent Chemicals, 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, BDH Ltd., Poole, Dorset, U
16、.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.6Grade F-3 has been found satisfactory and can be obtained from theAluminumCompany of America.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
17、PA 19428-2959, United States.required 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 WaterDistilled water passed through twomixed resin ion exchangers connected in series and having acon
18、ductance 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. Bureau of Internal Revenue may be substituted forethyl alcohol (95 %).5.7 Hydrochloric Acid, concen
19、trated.5.8 Ion-Exchange Cylinders.76. Safety Precautions6.1 Both trichlorotrifluoroethane and trichloromonofluoro-methane are not flammable and have threshold limit values of1000 ppm by volume in air. The respective boiling points ofthese solvents are about 118 and 75F (47.8 and 23.9C).Avoidrepeated
20、 skin contact with the solvents. They remove surfaceoils 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 toavoid contact with the body internally and externally. The acidis corrosive.
21、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, erroneously high values willbe obtained. Do the initial cleaning and the cl
22、eaning 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:7.2.1.1 Add about 30 g of ion exchange resin from anexchange cylinder to the i
23、tem 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 roller or its equivalent.7.2.1.4 Discard the ion-exchange resin and water, r
24、inse 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 delivery tubes in a 500-mLpolyethylene bottle.7.2.2.2 Clean by following 7.2
25、.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 from one con-tainer to another for at least 2 min.7.2.3.4 Discard the ion-excha
26、nge resin and deionized watermixture.7.2.3.5 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,
27、 into a clean250-mL polyethylene 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 e
28、quipment as described inaccordance 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
29、 water used to store the conductance dip-cellshould contain deionized water. This water will gradually adsorb carbon7Illco-Way ion exchange cylinders, research model, has been found satisfactoryand may be obtained from Illinois Water Treatment Co., Rockford, IL.FIG. 1 Alumina Gel ContractorD 3448 85
30、 (2005)2dioxide, 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 conductivityexceeds 1.0 S. During startup, the cell should be dipped in freshlydeionized
31、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-tion during the analysis.7.4.1 Add the selected trichloromonofluoromethane to thepol
32、yethylene 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.7.4.3 Discard the solvent.7.4.4 Add another 20 mL of the selected solvent to thebottle.
33、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-tivity bridge into the water layer.7.4.8 Measure and record conductivity value as t
34、he 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 Connect a polyethylene delivery tube to the cylinderof selected solvent.7.4.12 Slowly ope
35、n 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 Add100mLofselectedsolvent(trichloromonofluoro-methane) in this manner, filling to the 220-mLcalibrat
36、ion 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 the water layer as the secondconductance.7.4.17 Subtract the blank conductance fro
37、m 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 acceptable (see Note 5). The solventfound acceptable will be referred to as deionized
38、 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 remove thecontamination. The operation is a self-cleaning one, repeated testing oflow c
39、onductance 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 describedin 7.4.1-7.4.10.7.5.2 Tare weigh the polyethylene bottle containing thedeioni
40、zed 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 of a weighed sample.7.5.4 Recap the bottle tightly and shake it for 2 min.7.5.5 Op
41、en 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 fromatmospheric contamination. It should be left in the bottle until a new sample
42、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 materialcalculated as HCl. This value canbe expressed in ppm of HCl orppm of chlor
43、ide. (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 multiplierswitch setting; measurement of deionized water anddeionized trichloromonofluorome
44、thane),C3= cell constant in reciprocal centimetres, and52.4 = ppb HCl/S8,99. Precision and Bias9.1 The precision and bias are estimated to be about6 0.02S/cm.9.2 Repeatability and Reproducibility studies are planned.10. Keywords10.1 aqueous conductance; conductance8Lingane, J.J., Electroanalitical C
45、hemistry, Interscience Pub., Inc., New York,NY, 1953.9Berl, W.G., Physical Methods in Chemical Analysis, Vol 11, Academic Press,125 E. 23rd St., New York, NY, 1951.D 3448 85 (2005)3APPENDIX(Nonmandatory Information)X1. CALIBRATION OF 52.4 PPB HCl/SX1.1 The factor is a theoretical value and can be ca
46、lculatedfrom 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 bot
47、tle.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 oftrichloromonofluoromethane (X1.1)where:A = 3.65 3 106g HCl/0.01 mL of 0.01 N hydrochloricacid, andW = 150 g of t
48、richloromonofluoromethane per 100 mL.24 ppb HClC22 C1! C3!5 52.4 ppb HCl/S using the equipmentspecified in this test method! (X1.2)where:C2= second conductance value (dial reading 3 multiplierswitch setting, measurement of deionized water,deionized trichloromonofluoromethane and sample),C1= blank co
49、nductance value (dial reading 3 multiplierswitch setting, measurement of deionized water anddeionized trichloromonofluoromethane), andC3= cell constant in reciprocal centimetres.ASTM International takes no position respecting the validity 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 to revision at a
