1、Designation: F 1277 02Standard Test Method forDetermination of Leachable Chloride in Packing andGasketing Materials by Ion-Selective Electrode Technique1This standard is issued under the fixed designation F 1277; the number immediately following the designation indicates the year oforiginal adoption
2、 or, in the case of revision, the 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 provides for the measurement ofchloride ion leached from f
3、lexible graphite, asbestos, or paper-based packing and gasketing materials. Samples containing 7to 6700 g Cl-/g sample can be analyzed with this procedure.The upper concentration limit can be extended by dilution ofthe test solution.1.2 It is the responsibility of the analyst to ensure thevalidity o
4、f this test method for other packing or gasketingmaterials.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther
5、esponsibility 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. A specific warningstatement is given in 8.3.2. Referenced Documents2.1 ASTM Standards:D 512 Test Methods for Chloride Ion in Water
6、2E 50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated Materials3E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method4E 882 Guide for Accountability and Quality Control in theChemical Analysis
7、 Laboratory33. Summary of Test Method3.1 Chloride ion leached from packing and gasketing mate-rials is measured potentiometrically using a chloride ion-selective electrode in conjunction with a double junction,sleeve-type reference electrode. Potentials are read using apH/mV meter having 0.1 mV read
8、ability.3.2 A calibration curve is prepared by plotting the potentialsof known chloride solutions versus the corresponding concen-trations expressed in micrograms per millilitre. The chlorideconcentration of the test solution is determined from thecalibration curve, and this value is used to calcula
9、te the amountof chloride in parts per million that was leached from thepacking or gasketing material. The calibration and test solu-tions must be measured at the same temperature within 61C(62F).3.3 The calibration and test solutions are diluted with ionicstrength adjustor which also minimizes possi
10、ble interferencessuch as ammonia, bromide, iodide, cyanide, or sulfide (see TestMethods D 512).4. Significance and Use4.1 Chloride ion is highly detrimental to the valves, flanges,piping, etc. of stainless steel and copper-bearing alloys em-ployed in certain types of facilities, such as nuclear andc
11、hemical plants. Therefore, the amount of chloride ion that canbe leached from packing and gasketing materials used in thesefacilities must be controlled closely for prevention of damage.This test method is suitable for manufacturing control and forverifying that the packing and gasketing material me
12、ets speci-fications.4.2 It is assumed that the users of this test method will beanalysts capable of performing common laboratory proceduresskillfully and safely. It is recommended that the work will beperformed in a properly equipped laboratory under appropriatequality control practices such as thos
13、e described in GuideE 882.5. Interferences5.1 There is no interference from up to 500 g/mL ofsulfide, 1000 g/mL of bromide or iodide, a one hundred-foldexcess of cyanide over chloride, or 1000 g/mL of ammonia.Ferric, cupric, and permanganate ions do not interfere. Mer-cury must not be present.1This
14、test method is under the jurisdiction of ASTM Committee F03 on Gasketsand is the direct responsibility of Subcommittee F03.50 on Analytical Test Methods.Current edition approved October 10, 2002. Published October 2002. Originallypublished as F 1277 90. Last previous edition F 1277 95.2Annual Book o
15、f ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 03.05.4Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Digital pH/mV Meter, with 0.1 mV readability pre-ferred,
16、but 1 mV readability is acceptable.6.2 Chloride Ion-Selective Electrode (Cl-) , having a silverchloride (AgCl) membrane. (WarningChloride ion-selectiveelectrodes with a silver chloride/silver sulfide membrane arenot suitable as the sulfide can be oxidized by the ionic strengthadjustor used in this p
17、rocedure.)6.3 Sleeve-Type Double Junction Reference Electrode.NOTE 1Other types of double junction reference electrodes may besuitable, but supporting data included in this test method were obtainedwith only the recommended type.6.4 Oven.6.5 Desiccator, containing anhydrous calcium sulfate(CaSO4).6.
18、6 Hot Plate.6.7 Magnetic Stirrer, with polytetrafluorethylene (PTFE)-coated stirring bars.6.8 Beakers, 150 and 250-mL graduated capacities.6.9 Volumetric Flasks, 100, 500, and 1000-mL capacities.6.10 Volumetric Pipets, with 2, 5, 10, 25, and 50-mLcapacities.6.11 Graduated Cylinder, 10-mL capacity.6.
19、12 Watch Glasses, with ribs on the bottoms.6.13 Glass Stirring Rods.6.14 Glass Funnels.6.15 Filter Paper, with fast filtering rate.6.16 Polyethylene Bottles, 150, 500, and 1000-mL capaci-ties.6.17 Cotton Gloves.6.18 Scissors or Knife.7. Preparation of Reference Materials and Samples7.1 Preparation o
20、f Calibration Solutions:7.1.1 Seven solutions shall be prepared in order to calibratethe chloride ion-selective electrode. Each solution shall containa different concentration of chloride. Prepare the solutions asfollows:7.1.1.1 500 g/mL Cl-SolutionWith a 5-mL volumetricpipet, pipet 5 mL of 10 000 g
21、/mL Cl-stock solution into a100-mL volumetric flask. Bring the solution in the flask up tothe mark with distilled water and mix thoroughly.7.1.1.2 100 g/mL Cl-SolutionWith a 10-mL volumetricpipet, pipet 10 mL of 1000 g/mL Cl-stock solution into a100-mL volumetric flask. Bring the solution in the fla
22、sk up tothe mark with distilled water and mix thoroughly.7.1.1.3 50 g/mL Cl-SolutionWith a 5-mL volumetricpipet, pipet 5 mL of 1000 g/mL Cl-stock solution into a100-mL volumetric flask. Bring the solution in the flask up tothe mark with distilled water and mix thoroughly.7.1.1.4 10 g/mL Cl-SolutionW
23、ith a 10-mL volumetricpipet, pipet 10 mL of 100 g/mL Cl-stock solution into a100-mL volumetric flask. Bring the solution in the flask up tothe mark with distilled water and mix thoroughly.7.1.1.5 5 g/mL Cl-SolutionWith a 5-mL volumetricpipet, pipet 5 mL of 100 g/mL Clstock solution into a100-mL volu
24、metric flask. Bring the solution in the flask up tothe mark with distilled water and mix thoroughly.7.1.1.6 2.5 g/mL Cl-SolutionWith a 25-mL volumetricpipet, pipet 25 mL of 10 g/mL Cl-stock solution into a100-mL volumetric flask. Bring the solution in the flask up tothe mark with distilled water and
25、 mix thoroughly.7.1.1.7 1 g/mL Cl-SolutionWith a 10-mL volumetricpipet, pipet 10 mL of 10 g/mL Clstock solution into a100-mL volumetric flask. Bring the solution in the flask up tothe mark with distilled water and mix thoroughly.7.1.1.8 Transfer each solution to a labeled polyethylenebottle and cap
26、tightly.7.2 Preparation of Test and Blank Solutions:(WarningWhen preparing packing or gasketing materialsamples, precautions should be taken to avoid chloride con-tamination from handling. Clean cotton gloves should beworn.)7.2.1 Cut, with scissors or knife, or tear the packing orgasketing material
27、into pieces 6 to 12 mm (14 to12 in.) square.7.2.2 Dry the sample in an oven set at approximately 100C(212F) for a minimum of 1 h.NOTE 2If it can be demonstrated that equivalent precision can beobtained without drying the samples, this step may be eliminated.7.2.3 Remove the sample from the oven, pla
28、ce in a desic-cator, and cool to room temperature. Weigh 15 g of samplematerial to the nearest 0.01 g, place in a 250-mL beaker, andlabel.7.2.4 Add 90 mL of distilled water to the beaker. Using a10-mL graduated cylinder, add 10 mL of 0.1 M NaOH.7.2.5 Preparation of Blank SolutionPrepare a blank solu
29、-tion by adding 90 mL of distilled water and 10 mL of 0.1 MNaOH to a 250-mL beaker. Treat the blank solution in the samemanner as the test solution, but do not stir.7.2.6 Cover the beaker with a ribbed watch glass and digestthe specimen at 90 6 5C (195 6 10F) for a minimum of4 h. Stir the specimen o
30、ccasionally (at least once per hour).(WarningUse glass rods to stir specimens during digestion.Using a magnetic stirrer may cause the sample material toagglomerate.)7.2.7 Remove the test solution from the hot plate and cool.Place a filter paper in a glass funnel and moisten with distilledwater. Filt
31、er the test solution into a 100-mL volumetric flask.Wash the material in the beaker with about 15 mL of distilledwater and filter washings into flask. Repeat the washing step ifpossible, but do not let the volume in the flask exceed the100-mL mark. Bring the solution in the flask up to 100-mLvolume
32、with distilled water and mix thoroughly. (WarningMake sure that the sample is washed sufficiently, but the finalvolume of the test solution must be restricted to 100 mL.)8. Reagents and Materials8.1 Purity and Concentration of ReagentsThe purity andconcentration of the chemical reagents used shall b
33、e inaccordance with the requirements prescribed in Practices E 50.8.2 Solutions for Filling Double Junction Reference Elec-trode:8.2.1 Inner-Chamber Filling Solution, available from theelectrode manufacturer.8.2.2 Outer-Chamber Filling SolutionUse the solutionprepared in 8.3.F12770228.3 Chloride Ion
34、ic Strength Adjustor (CISA)Dissolve15.1 g of sodium bromate (NaBrO3) in 800 mL of distilledwater. Add 75 mL of concentrated nitric acid (HNO3, specificgravity 1.42) and stir well. Dilute with distilled water to 1 L.Store CISA in a polyethylene or glass bottle. (WarningForlow level chloride measureme
35、nts (less than 5 mg/L), the nitricacid used must not contain more than 0.005 % chloride and thesodium bromate must not contain more than 0.003 % chloride.)(WarningSodium bromate is a strong oxidant and should behandled with care. The preparation and dilution of CISAshould be made in a well-ventilate
36、d area, preferably in a hood.)8.4 10 000 g/mL Cl-Stock SolutionPlace about 20 g ofsodium chloride (NaCl) in a weighing bottle and dry in an ovenat 110C (230F) for 1 h. Remove weighing bottle from oven,place in a desiccator, and cool to room temperature. As quicklyas possible, weigh 16.485 g of the d
37、ried NaCl and place in a500-mL beaker. Dissolve the NaCl with distilled water. Usinga glass funnel, transfer the NaCl solution to a 1-L volumetricflask. Wash the beaker with a small quantity (40 to 50 mL) ofdistilled water and transfer washings to flask. Repeat washingstep five times. Bring solution
38、 in flask up to the mark withdistilled water and mix thoroughly. Store in a labeled 1000-mLpolyethylene bottle.8.5 1000 g/mL Cl-Stock SolutionWith a 10-mL volu-metric pipet, pipet 10 mL of the 10 000 g/mL Cl-stocksolution into a 100-mL volumetric flask. Bring the solution inthe flask up to the mark
39、with distilled water and mix thor-oughly. Store in a labeled 150-mL polyethylene bottle.8.6 100 g/mL Cl-Stock SolutionWith a 10-mL volumet-ric pipet, pipet 10 mL of the 1000 g/mL stock solution into a100-mL volumetric flask. Bring the solution in the flask up tothe mark with distilled water and mix
40、thoroughly. Store in alabeled 150-mL polyethylene bottle.8.7 10 g/mL Cl-Stock SolutionWith a 10-mL volumetricpipet, pipet 10 mL of the 100 g/mL stock solution into a100-mL volumetric flask. Bring the solution in the flask up tothe mark with distilled water and mix thoroughly. Store in alabeled 150-m
41、L polyethylene bottle.8.8 0.1 M Sodium Hydroxide Stock Solution (NaOH)Weigh 4.0 g 6 0.1 g of NaOH and place in a 250-mL beaker.Add 50 mL of distilled water to the beaker slowly whilestirring constantly with a glass stirring rod. Stir until NaOH isdissolved completely. Using a glass funnel, transfer
42、the NaOHsolution to a 1-L volumetric flask. Wash beaker with a smallquantity (40 to 50 mL) of distilled water and transfer washingsto flask. Bring solution in flask up to the mark with distilledwater and mix thoroughly. Store in a 1000-mL polyethylenebottle.9. Preparation of Apparatus9.1 Prepare and
43、 operate the pH/mV meter in accordancewith the manufacturers instructions.NOTE 3It is not within the scope of an ASTM test method to prescribeminute details relative to the preparation of the apparatus. For a descrip-tion and specific details concerning the operation of a particular piece ofequipmen
44、t, refer to the manufacturers manual.9.2 Use and care for the chloride ion-selective electrode andthe reference electrode in accordance with the manufacturersinstructions (see Note 3). (WarningIt is important to keepthe flat end of the electrode well-polished, but care should betaken not to damage i
45、t.)9.2.1 Fill the inner and outer chambers of the referenceelectrode with the recommended solutions (see 8.2.1 and8.2.2).10. Calibration10.1 Label seven clean and dry 150-mL beakers with thechloride concentrations of the seven calibration solutions. Adda stirring bar to each beaker, and pipet 25 mL
46、of the appropriatecalibration solution into the variously labeled beakers.10.2 Pipet 25 mL of CISA into each beaker.10.3 Place the chloride ion-selective electrode and thereference electrode in the calibration solution of lowest chlo-ride concentration (that is, 1 g/mL) and turn on the magneticstirr
47、er. With the pH/mV meter in the mV mode, wait 1 to 2 minand then record the potential observed.10.4 Remove the electrodes from the solution, rinse withdistilled water using a wash bottle, and gently wipe them drywith a soft paper wiper.10.5 Measure the potentials of the other calibration solu-tions
48、as described in 10.3 and 10.4. Begin with the 2.5 g/mLCl-solution and proceed stepwise to the next solution of higherconcentration.NOTE 4A stable potential reading may be obtained in less than 1 minfor calibration solutions with higher chloride concentrations.10.6 The calibration curve should be lin
49、ear at chlorideconcentrations greater than 5 g/mL, with a slope of 58 6 3mV. Estimate the slope of the linear portion of the curve bytaking the difference in potential between the 10 and 100g/mL calibration solutions. If the slope is not 58 6 3 mV, thisindicates that either the pH/mV meter or one, or both, of theelectrodes may be malfunctioning and requires servicing, orthat one of the calibration solutions was prepared improperly.If the potential does differ by 58 6 3 mV, proceed to preparethe calibration curv
