1、Designation: D3831 12 (Reapproved 2017)Standard Test Method forManganese in Gasoline By Atomic AbsorptionSpectroscopy1This standard is issued under the fixed designation D3831; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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. Scope1.1 This test method covers the determination of the totalmanganese content, present as methylcyclopentadienyl manga
3、-nese tricarbonyl (MMT),2of gasoline within the concentrationrange from 0.25 mg L to 40 mg L of manganese.1.2 This test method is applicable to reformulated gasolinecontaining up to 12 % volume methyl tertiary butylether or upto 10 % volume ethanol. This test method may not be appli-cable to highly
4、cracked materials containing greater than 18 %by volume olefins as determined by Test Method D1319(nondepentanized).1.3 This test method has been developed and tested specifi-cally for the determination of MMT in gasoline over therecommended concentration range. Application of the methodto other con
5、centration ranges, to the determination of MMT inother materials, or to the determination of other manganesecompounds in gasoline have not been tested1.4 The values stated in SI units are to be regarded as thestandard. The preferred concentration units are mg/L manga-nese.1.5 This standard does not
6、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. For specificwarning statements, see Secti
7、ons 5 and 6.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization Technica
8、lBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3D1319 Test Method for Hydrocarbon Types in Liquid Petro-leum Products by Fluorescent Indicator AdsorptionD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petrole
9、um andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsD6792 Practice f
10、or Quality Management Systems in Petro-leum Products, Liquid Fuels, and Lubricants TestingLaboratoriesD7740 Practice for Optimization, Calibration, and Valida-tion of Atomic Absorption Spectrometry for Metal Analy-sis of Petroleum Products and Lubricants3. Summary of Test Method3.1 The gasoline samp
11、le is treated with bromine solutionand diluted with methyl isobutyl ketone. The manganesecontent of the sample is determined by atomic absorptionspectrometry using an air-acetylene flame at 279.5 nm andstandards prepared from an organo-manganese standard mate-rial.3.2 Protocols for using atomic abso
12、rption spectrometry aregiven in Practice D7740.4. Significance and Use4.1 Certain organo-manganese compounds act as antiknockagents when added to gasoline. This test method provides ameans for determining the concentration of such a material ina gasoline sample.1This test method is under the jurisdi
13、ction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved May 1, 2017. Published June 2017. Originallyapproved in 1979. Last previous edition approved in 2012 as D3831 12. DOI:1
14、0.1520/D3831-12R17.2MMT is a registered trademark of Ethyl Corp.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM websi
15、te.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of In
16、ternational Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15. Apparatus5.1 Atomic Absorption Spectrometer, capable of scale ex-pansion and equipped with a manganese hollow-cathode lampfor monitoring manganese absorption at 27
17、9.5 nm, a premixslot-type burner with rotatable burner head, and an adjustablenebulizer. (WarningHazardous. Potentially toxic and explo-sive. Refer to the manufacturers instrument manual for asso-ciated safety hazards.)5.2 Vials, up to 40 mL size with polyethylene or TFE-fluorocarbon-lined caps or g
18、lass stoppers.5.3 Pipet, Delivery, 1 mL size.5.4 Micropipet, 100 L size, Eppendorf type or equivalent.5.5 Automatic Pipet, or equivalent delivery pipet, capable ofdelivering 9.0 mL quantities.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicat
19、ed, it is intended 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 permi
20、t its use without lessening theaccuracy of the determination.6.2 Bromine SolutionAdd reagent grade bromine to anequal volume of cyclohexane. (WarningBromine can causesevere and painful burns when it contacts the skin. In additionto other precautions, wear protective gloves in preparing thesolution a
21、nd prepare, store, and use it in a well-ventilatedhood.)6.3 Manganese Standard Solution 400 mg Mn/LDissolvethe appropriate amount of organometallic manganese standardin methyl isobutyl ketone to give a standard solution of 400 mgMn/L.6.4 Manganese, Standard Solution 4.0 mg, 10.0 mg,20.0 mg, and 40.0
22、 mg Mn/LDilute the 400 mg L standardmanganese solution with methyl isobutyl ketone using volu-metric glassware to give the desired lower concentrationmanganese standard solutions.6.5 Organometallic Manganese StandardPre-preparedcommercially available organometallic stock solutions havebeen found to
23、be satisfactory.6.6 Methyl Isobutyl Ketone, reagent grade. (WarningFlammable. Vapor harmful.) (Warning Solutions of MMTin gasoline are chemically unstable when exposed to light. Lowand erratic results may be obtained if the gasoline sample isexposed to light prior to stabilization during analysis.)6
24、.7 Quality Control (QC) Sample(s),preferably are a portion of one or more gasoline materials thatare stable and representative of the samples of interest.7. Sampling7.1 Take samples of gasoline in compliance with the in-structions in Practice D4057 or D4177 where appropriate.Analyze as soon as possi
25、ble after sampling.8. Calibration8.1 Preparation of Working Standards Prepare four work-ing standards using the 4.0 mg, 10.0 mg, 20.0 mg, and 40.0 mgMn/L standard manganese solutions described in 6.3.8.1.1 Using a micropipet, add 100 L of bromine solution toeach of four separate vials.8.1.2 Pipet 1
26、mL of each of the four low-manganese stan-dards into each of the vials. Mix with the bromine solution byswirling the vials.8.1.3 Deliver 9.0 mL of methyl isobutyl ketone to each ofthe vials. Mix well. This tenfold dilution of the low-manganesestandards is the same as the final dilution of the sample
27、.8.2 Preparation of InstrumentSet the atomic absorptionspectrometer operating conditions to those recommended bythe manufacturer for monitoring manganese absorption at279.5 nm using an air-acetylene flame. This test methodassumes that good operating procedures are followed. Designdifferences between
28、 spectrometers make it impractical toexactly specify required instrument settings.8.2.1 Nebulize methyl isobutyl ketone into the flame.Adjustthe nebulizer (sample flow rate), acetylene, and air flow rates togive a lean, nonluminous flame.8.2.2 With methyl isobutyl ketone as a blank, nebulize, inturn
29、, the four working standards.NOTE 1Record the absorbances and check these data for linearity. Ifnonlinear, readjust the sample or acetylene flow rates, or both, slightly toleaner conditions and repeat the calibrations until absorbances are linear.Rotation of the burner head to decrease the absorbanc
30、e may aid inachieving linearity.NOTE 2Three working standards may be used to cover the expectedconcentration range of the samples. Fuel specification limits should beconsidered. For example, the use of the high 40 mg/L standard may not benecessary.9. Procedure9.1 Deliver 100 L of bromine solution in
31、to a vial.9.2 Add 1.0 mL of the gasoline sample. Mix well.9.3 Add 9.0 mL of methyl isobutyl ketone. Mix well.9.4 Aspirate the working standards and the sample into theflame and record the absorbances of each.NOTE 3Measure absorbances of the working standards and thesamples promptly as the sample abs
32、orbances may change with time.10. Calculations10.1 The direct concentration read out of the instrument isthe preferred mode of quantification. Alternatively, plot theabsorbance values that were obtained by aspirating the workingstandard solutions versus manganese concentration and drawthe best strai
33、ght line through the points. From the plot read the4Reagent 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., P
34、oole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D3831 12 (2017)2manganese concentration corresponding to the absorbance ofthe gasoline sample. Report the manganese content of thegasoline to the nearest 0.1 mg L Mn
35、.11. Quality Control11.1 Confirm the performance of the test procedure byanalyzing a quality control (QC) sample that is stable andrepresentative of the sample of interest.11.2 When the quality control/quality assurance protocolsare already established in the testing facility, these may be usedto co
36、nfirm the reliability of the test result.11.3 When there is no quality control/quality assuranceprotocol established in the testing facility, Appendix X1 can beused to perform this function.11.4 Further guidance on QA/QC can be found in PracticeD6792.12. Precision and Bias12.1 Precision5The precisio
37、n of this test method as ob-tained by statistical examination of interlaboratory test resultsfrom eleven samples of motor gasoline, covering concentrationrange of 0.25 mg L to 40 mg L manganese, run in duplicate byeleven laboratories is as follows:12.1.1 Repeatability The difference between successi
38、vetest results, obtained by the same operator with the sameapparatus under constant operating conditions on identical testmaterial, would in the long run, in the normal and correctoperation of the test method, exceed the following values onlyin one case in twenty:0.3308=x10.1062! mg Mn/L (1)where x
39、= average of the two results.12.1.2 Reproducibility The difference between two singleand independent results, obtained by different operators work-ing in different laboratories on identical test material, would inthe long run, in the normal and correct operation of the testmethod, exceed the followi
40、ng values only in one case intwenty:1.650=x10.1062! mg Mn/L (2)where x = average of the two results.12.2 BiasThe bias for the procedure in this test methodcannot be determined, since a suitable reference material is notavailable.13. Keywords13.1 AAS; atomic absorption spectroscopy; gasoline; man-gan
41、ese; methylcyclopentadienyl manganese tricarbonyl; MMTAPPENDIX(Nonmandatory Information)X1. QUALITY CONTROLX1.1 Confirm the performance of the instrument or the testprocedure by analyzing a quality control (QC) sample that is,if possible, representative of the samples typically analyzed.X1.2 Prior t
42、o monitoring the measurement process, the userof the method needs to determine the average value and controllimits of the QC sample. See Practices D6299, D6300, andMNL 7.6X1.3 Record the QC results and analyze by control charts orother statistically equivalent techniques to ascertain the statis-tica
43、l control status of the total testing process. See PracticesD6299, D6300, and MNL 7.6Any out-of-control data shouldtrigger investigation for root cause(s). The results of thisinvestigation may, but not necessarily, result in instrumentrecalibration.X1.4 In the absence of explicit requirements given
44、in thetest method, the frequency of QC testing is dependent on thecriticality of the quality being measured, the demonstratedstability of the testing process, and customer requirements.Generally, a QC sample is analyzed each testing day withroutine samples. The QC frequency should be increased if al
45、arge number of samples are routinely analyzed. However,when it is demonstrated that the testing is under statisticalcontrol, the QC testing frequency may be reduced. The QCsample precision should be periodically checked against theASTM method precision to ensure data quality. See PracticeD6300.X1.5
46、It is recommended that, if possible, the type of QCsample that is regularly tested be representative of the samplesroutinely analyzed. An ample supply of QC material should beavailable for the intended period of use, and must be homoge-neous and stable under the anticipated storage conditions.X1.6 S
47、ee Practices D6299, D6300, or MNL 76for furtherguidance on QC and Control Charting techniques.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1500. ContactASTM CustomerService at serviceastm.org.6ASTM MNL 7 “Manual on Presen
48、tation of Data Control Chart Analysis,” 6thed., Section 3: Control Chart for Individuals, available from ASTM Headquarters.D3831 12 (2017)3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this s
49、tandard 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 any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a m
