1、Designation: D7959 16Standard Test Method forChloride Content Determination of Aviation Turbine Fuelsusing Chloride Test Strip1This standard is issued under the fixed designation D7959; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers a rapid means of determiningchloride content of aviation turbine fuel. This me
3、thodology isapplicable for chloride concentrations between 0 mg L to0.3 mg L. This methodology will not detect chlorine originat-ing from chlorinated organic compounds (that is, covalentbond).1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included
4、in thisstandard.1.3 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use
5、.2. Referenced Documents2.1 ASTM Adjuncts:Distillate Fuel Bar Chart23. Summary of Test Method3.1 A 3 L sample of aviation turbine fuel is extracted withpH 7 buffer solution by a magnetic stir plate and stir bar. Thechloride in the aviation turbine fuel sample transfers to thebuffer solution. A porti
6、on of the aqueous extract solution isthen removed and analyzed with a chloride test strip. Silverions within the test strip combine with chloride ions in theextract as it is drawn up by capillary action to form a whitecolumn of silver chloride. The chloride concentration of theextract, determined by
7、 the height of the column, is then relatedback to the chloride content of the aviation turbine fuel sample.4. Significance and Use4.1 Chloride present in aviation turbine fuel can originatefrom refinery salt drier carryover or possibly from seawatercontamination (for example, product transferred by
8、barge).Elevated chloride levels have caused corrosive and abrasivewear of aircraft fuel control systems leading to engine failure.35. Interferences5.1 Some pH 7 buffer solution can contain trace levels ofchloride compounds and therefore produce a false positivereading on the chloride test strip. Pri
9、or to using a new batch ofpH 7 buffer solution, a sample should be confirmed to produceno reading on the chloride test strip.5.2 The test strip4will react with halides other than chloride(for example, bromide, iodide). The concentration of chloridein salt used in refinery salt driers (predominantly
10、NaCl andCaCl2) and in seawater, however, is in great excess comparedto that of other halides.6. Apparatus6.1 Magnetic Stir Plate and Stir BarThe magnetic stirplate shall be capable of producing the stirring energy de-scribed in Section 11.11. A magnetic stir bar in the form of across or “starburst”
11、approximately 32 mm by 32 mm hasproven to be more stable than the traditional bar shape. The stirbar shall have a chemically inert coating such as polytetrafluo-roethylene (PTFE).6.2 Distillate Fuel Bar Chart.27. Reagents and Materials7.1 Isooctane (2,2,4trimethylpentane, CAS #540-84-1)Minimum ACS r
12、eagent grade purity.7.2 pH 7 Buffer SolutionSome pH 7 buffer solution cancontain trace levels of chloride compounds and thereforeproduce a false positive reading on the chloride test strip. Prior1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and
13、 Lubricants and is the direct responsibility ofSubcommittee D02.J0.05 on Fuel Cleanliness.Current edition approved Dec. 1, 2016. Published January 2017. Originallyapproved in 2015. Last previous edition approved in 2015 as D7959 15. DOI:10.1520/D7959-16.2Available from ASTM International Headquarter
14、s. Order Adjunct No.ADJD417601. Original adjunct produced in 1991.3Guidelines for Sodium Chloride Contamination Troubleshooting and Decon-tamination of Airframe and Engine Fuel Systems, International Air TransportAssociation, 2nd Ed., February 1998, pg. 1.4The sole source of supply of the apparatus
15、(Chloride QuanTab (trademarked)Test Strips, 30 600 mg/L) known to the committee at this time is Hach Company,P.O. Box 389, Loveland, Colorado 80539-0389, http:/. If you areaware of alternative suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive
16、careful consideration at a meetingof the responsible technical committee,1which you may attend.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard
17、 was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1to using
18、a new batch of pH 7 buffer solution, a sample shouldbe confirmed to produce no reading on the chloride test strip.NOTE 1Prior batches of Fisher Scientific pH 7 buffer solution, catalognumber SB108, have produced no reading on the chloride test strips.7.3 Chloride Test Strips4The conversion of the di
19、men-sionless test strip value to chloride concentration in mg/Lfound on the test strip container varies slightly from one lot ofchloride test strips to the next.8. Hazards8.1 If a combination heater and stir plate is to be used,ensure the heater is off.9. Sampling, Test Specimens, and Test Units9.1
20、The sample should be obtained for testing in either a1 gal or 5 L container.9.2 Collect a sample of at least 3 L.10. Preparation of Apparatus10.1 Unless otherwise stated, all glassware should becleaned prior to use. No special cleaning or rinsing procedureis required.11. Procedure11.1 Vigorously sha
21、ke the sample container by hand forapproximately 15 s before analysis.11.2 Add 3 L of the aviation turbine fuel test sample to a 4 Lbeaker by filling and emptying a 1 L graduated cylinder threetimes.11.3 Remove the remaining fuel from the sample container.11.4 Completely drain the sample container (
22、discarding anyresidual fuel) by means of one of the following methods.11.4.1 If the sample container has a spout and can beeffectively drained (see Fig. 1), drain upside down for 2 min,tilting and shaking occasionally to remove any residual fuel.11.4.2 If the sample container does not have a spout a
23、ndcannot be effectively drained, tilt the sample container to theside or to a corner so that any residual fuel collects beneath thesample container opening (see Fig. 2). Wait approximately2 min. Remove any residual fuel with a clean pipette. Wait anadditional approximate 2 min and repeat (the same p
24、ipette maybe used).11.5 Add 5 mL pH 7 buffer solution by pipette to the nowempty sample container.11.6 Cap the sample container tightly and hand shakevigorously for approximately 1 min. Try to have the pH 7buffer solution contact all inside surfaces of the container. Theuse of a shaker table is not
25、recommended since the buffersolution will not contact all inside surfaces of the container.11.7 Transfer the contents to the 4 L beaker via one of thefollowing methods.11.7.1 If the sample container has a spout and can beeffectively drained, drain upside down for approximately 30 s,tilting and shaki
26、ng occasionally to transfer any residual buffersolution.11.7.2 If the sample container does not have a spout andcannot be effectively drained, tilt the sample container to theside or to a corner so that the buffer solution collects beneaththe sample container opening. Tap the side or corner a fewtim
27、es lightly on a benchtop to encourage the buffer solution tocollect. Wait approximately 30 s. Transfer the buffer solutionwith a clean, 20 mL (or larger) pipette. Wait an additionalapproximate 30 s and repeat to ensure all the buffer solution isdelivered to the 4 L beaker. Set the pipette aside for
28、later use;do not clean. Lay the pipette down horizontally with no contactto the tip so that any residual buffer solution is not lost.11.8 Add 20 mL isooctane to the sample container with anew, clean pipette.11.9 Cap the sample container tightly and hand shakevigorously for approximately 1 min.11.10
29、Transfer the isooctane rinse to the 4 L beaker bymeans of one of the following methods.11.10.1 If the sample container has a spout and can beeffectively drained, drain upside down for approximately 30 s,tilting and shaking occasionally to transfer any residual isooc-tane.11.10.2 If the sample contai
30、ner does not have a spout andcannot be effectively drained, tilt the sample container to theside or to a corner so that the isooctane collects beneath thesample container opening. Tap the side or corner a few timeslightly on a benchtop to encourage the isooctane to collect.Wait approximately 30 s. R
31、emove isooctane with the pipette,previously set aside. Wait an additional approximate 30 s andrepeat to ensure all isooctane is delivered to the 4 L beaker.NOTE 2Despite the isooctane rinse, there will most likely be buffersolution residue remaining within the pipette.11.11 Tape a Distillate Fuel Ba
32、r Chart to the beaker (see Fig.3). The chart, which is double-sided, should be taped so that theleft and right sides conform to and make contact with the 4 Lbeaker and so the bottom of the card is flush with the stir platesurface. Add a magnetic stir bar to the 4 L beaker. Ensuring thestir bar is ce
33、ntered in the bottom of the beaker will helpminimize any splashing. Stir at a setting at which line 5 of theDistillate Fuel Bar Chart is no longer visible. Figs. 4 and 5illustrate inadequate and adequate stirring, respectively. Stir for10 min. After 10 min, remove the 4 L beaker from the stir platea
34、nd remove the stir bar.11.12 Obtain a few millilitres of the extract (lower layer) bymeans of one of the following methods and place into asuitable container (an 8 dram vial is ideal). Removing someaviation turbine fuel with the extract will not impact testresults.11.12.1 Tilt beaker on its side, le
35、t settle for approximately15 min. Carefully and slowly decant approximately 2.5 L ofthe aviation turbine fuel. Swirl remaining material and tiltbeaker on its side for an additional approximate 2 min. Obtainextract by pipette. See Figs. 6-8.11.12.2 Let beaker settle for approximately 15 min, care-ful
36、ly and slowly decant approximately 2.5 L of the aviationturbine fuel, swirl the remaining material then transfer to anappropriate sized separatory funnel, let settle an additional5 min, then drain extract.D7959 16211.13 Add a chloride test strip to the extract and wait untilyellow, horizontal band a
37、t the top of the scale turns dark (seeFig. 9).12. Calculation or Interpretation of Results12.1 Read the test strip to the nearest 0.1 (the graduations onthe test strip are 0.2). Convert the test strip reading to mg/Lchloride (to the nearest whole number) for the extract using thescale on the test st
38、rip container.12.1.1 The operator may need to interpolate between scalereadings.12.2 Multiply this value by 0.0017 to determine chloridecontent in mg/L of the aviation turbine fuel. The factor of0.0017 converts the chloride concentration in the 5 mL extractback to that of the 3 L test sample as foll
39、ows:5 mL extract (1 L/1000 mL) (X mg Cl-/L) / (3 L aviationturbine fuel sample)13. Report13.1 Report the following information:13.1.1 Date of analysis.13.1.2 Operator.13.1.3 pH 7 buffer manufacturer, lot number, and use bydate.13.1.4 Chloride test strip lot number and use by date (forexample, Use By
40、: 02/2013 Lot A3253).13.1.5 Chloride test strip result to the nearest 0.1 (forexample, 1.9).13.1.6 Chloride concentration of the extract, mg/L, to thenearest whole number (for example, 50).13.1.7 Chloride concentration of the aviation turbine fuelsample to two decimal places (for example, 0.08 mg/L)
41、.13.1.8 Reference this test method.14. Precision and Bias14.1 RepeatabilityA ruggedness study was performed byanalyzing aviation turbine fuel samples additized with differentchloride concentrations. Dodecyltrimethylammonium chloride,CAS #112-00-5, was solubilized in methanol and added to eachindivid
42、ual aviation turbine fuel sample by mechanical pipette.Ten aviation turbine fuel samples were prepared and analyzedat each of three different chloride concentrations by a singleoperator. The calculated average values and the repeatabilityare shown in Table 1. An interlaboratory study of this testmet
43、hod is being conducted and a complete precision statementis expected to be available on or before July 1, 2018.14.2 ReproducibilityTo be determined.14.3 BiasSince there is no accepted reference materialsuitable for determining the bias in this test method, bias hasnot been determined.15. Keywords15.
44、1 aviation turbine fuel; chloride; cleanliness; contamina-tion; jet fuel; Jet A; Jet A-1; salt; seawaterD7959 163FIG. 1 Draining of Sample Container with a SpoutFIG. 2 Draining of Sample Container with No SpoutFIG. 3 Taping of Double-Sided Distillate Fuel Bar Chart to 4 LBeakerFIG. 4 Inadequate Stir
45、 Speed (that is, Bars Still Visible)D7959 164FIG. 5 Adequate Stir Speed (that is, Bars No Longer Visible)FIG. 6 Test Fuel Before DecantingFIG. 7 Test Fuel After DecantingD7959 165FIG. 9 Chloride Test StripFIG. 8 Close-Up of ExtractTABLE 1 Precision InformationSample Replicates Average, mg/L rA 10 0.
46、07 0.01B 10 0.14 0.07C 10 0.25 0.10D7959 166APPENDIX(Nonmandatory Information)X1. ESTIMATION OF CHLORIDE CONCENTRATION WHEN LESS THAN A 3 L TEST SAMPLE IS AVAILABLEX1.1 In order to quantify very low chloride concentrations,this test method requires a relatively large sample size (that is,3 L). There
47、 may be a need to determine chloride concentrationwhen less than the required 3 L sample size is available. In thiscase, the following calculations can be used to provide anestimate of chloride concentration. The result, however, shouldnot be reported according to this method and the precisioninform
48、ation above in Section 14 would not be applicable.Although testing has not been conducted to confirm, precisionshould directionally improve as test sample size approaches3L.X1.2 Example:X1.2.1 Sample size is 2500 mL.X1.2.2 Chloride test strip result of 1.9 equates to a chlorideconcentration of 50 mg
49、/L.X1.2.3 5 mL extract(1L/1000 mL)(50 mg Cl-/1 L extract)(1/2500 mL sample)(1000 mL/1 L) = 0.10 mg/L Cl-.SUMMARY OF CHANGESSubcommittee D02.J0 has identified the location of selected changes to this standard since the last issue(D7959 15) that may impact the use of this standard. (Approved Dec. 1, 2016.)(1) Revised title.(2) Revised subsections 1.1, 12.2, 14.1, X1.1, and availabilityinformation in footnote 4.(3) Added new subsection 5.2.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any
