1、Designation: D3831 12Standard 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 year of last revisio
2、n. 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 the determination of the totalmanganese content, present as methylcyclopentadienyl manga-nese tricarbonyl
3、 (MMT),2of gasoline within the concentrationrange from 0.25 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 cracked materials cont
4、aining greater than 18volume % 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 concentration ranges, to the
5、 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 purport to address all of
6、 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 Sections 5 and 6.2. Referenced
7、 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 Petroleum andPetroleum ProductsD6299 Practice for Apply
8、ing 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 for Quality System in Petroleum Productsand Lubri
9、cants Testing LaboratoriesD7740 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 sample is treated with bromine solutionand diluted with methyl isobutyl ketone.
10、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 absorption spectrometry aregiven in Practice D7740.4. Significance and Use4.1 Ce
11、rtain 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.5. Apparatus5.1 Atomic Absorption Spectrometer , capable of scaleexpansion and equipped with a manganese hollow-ca
12、thodelamp for monitoring manganese absorption at 279.5 nm, apremix slot-type burner with rotatable burner head, and anadjustable nebulizer. (WarningHazardous. Potentially toxicand explosive. Refer to the manufacturers instrument manualfor associated safety hazards.)5.2 Vials, up to 40-mL size with p
13、olyethylene or TFE-fluorocarbon-lined caps or glass stoppers.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved June 1, 2012. Published August 2012
14、. Originallyapproved in 1979. Last previous edition approved in 2006 as D3831 01(2006).DOI: 10.1520/D3831-12.2MMT 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 ASTMS
15、tandards volume information, refer to the standards Document Summary page onthe ASTM website.*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 States15.3 Pipet, Delivery, 1-mL si
16、ze.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 indicated, it is intended thatall reagents shall
17、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 lessening theaccuracy of
18、 the determination.6.2 Bromine Solution Add 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 and prepare, store, and use it in a well-v
19、entilatedhood.)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, 10.0, 20.0, and 40.0mg Mn/LDilute the 400 mg/L standard manganese sol
20、utionwith methyl isobutyl ketone using volumetric glassware to givethe desired lower concentration manganese standard solutions.6.5 Organometallic Manganese Standard Pre-preparedcommercially available organometallic stock solutions havebeen found to be satisfactory.6.6 Methyl Isobutyl Ketone, reagen
21、t 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.)6.7 Quality Control (QC) Sample(s) ,preferably are
22、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 possible after sampling.8. Calibration8.1 Preparation
23、of Working Standards Prepare four work-ing standards using the 4.0, 10.0, 20.0, and 40.0 mg Mn/Lstandard 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 mL of each of the four low-manganesestandards into each of
24、 the vials. Mix with the bromine solutionby swirling 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.8.2 Preparation of InstrumentSet the atomic absorptionspect
25、rometer 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 spectrometers make it impractical toexactly specify require
26、d 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, the four working standards.NOTE 1Record the absorbances an
27、d 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 absorbance may aid inachieving linearity.NOTE 2Three working standard
28、s 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 into a vial.9.2 Add 1.0 mL of the gasoline sample. Mix well.9.
29、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 absorbances may change with time.10. Calculations10.1 The direc
30、t 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 straight line through the points. From the plot read themanganese
31、 concentration corresponding to the absorbance ofthe gasoline sample. Report the manganese content of thegasoline to the nearest 0.1 mg/L Mn.11. Quality Control11.1 Confirm the performance of the test procedure byanalyzing a quality control (QC) sample that is stable andrepresentative of the sample
32、of interest.11.2 When the quality control/quality assurance protocolsare already established in the testing facility, these may be usedto confirm the reliability of the test result.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions
33、 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. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D3831 12211.3 When there is no quali
34、ty 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 precision of this test method as ob-tained by statistical examination of int
35、erlaboratory test resultsfrom eleven samples of motor gasoline, covering concentrationrange of 0.25 to 40 mg/L manganese, run in duplicate byeleven laboratories is as follows:12.1.1 Repeatability The difference between successivetest results, obtained by the same operator with the sameapparatus unde
36、r 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 = average of the two results.12.1.2 Reproducibility The difference betwee
37、n 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 following values only in one case intwenty:1.650=x10.1062! mg Mn/L (2)where x =
38、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-ganese; methylcyclopentadienyl manganese tricarbonyl; MMTAPPENDIX(Nonmandato
39、ry 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 to monitoring the measurement process, the userof the method needs to dete
40、rmine 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-tical control status of the total testing process. See PracticesD6299, D6300,
41、 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 in thetest method, the frequency of QC testing is dependent on thecritica
42、lity 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 alarge number of samples are routinely analyzed. However,when it is demonst
43、rated 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 It is recommended that, if possible, the type of QCsample that is regular
44、ly 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 See Practices D6299, D6300, or MNL 76for furtherguidance on QC and Control
45、 Charting techniques.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1500.6ASTM MNL 7 “Manual on Presentation of Data Control Chart Analysis,” 6thed., Section 3: Control Chart for Individuals, available from ASTM Headquarter
46、s.D3831 123SUMMARY OF CHANGESSubcommittee D02.03 has identified the location of selected changes to this standard since the last issue(D3831 01(2006) that may impact the use of this standard.(1) Added 3.2 and 11.4. (2) Added Practices D6792 and D7740.ASTM International takes no position respecting t
47、he 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
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49、eadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-8
