1、Designation: D3257 06 (Reapproved 2012)Standard Test Methods forAromatics in Mineral Spirits by Gas Chromatography1This standard is issued under the fixed designation D3257; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These test methods cover the dete
3、rmination of ethylben-zene and total eight-carbon (C8) and heavier aromatics in theconcentration range from 0.1 to 30 % in mineral spirits havinga distillation range from 149 to 210C (300 to 410F) asdetermined by Test Method D86. The procedures permit theidentification and calculation of concentrati
4、ons of aromaticcomponents to 0.1 volume %.1.2 It is recognized by analytical chemists that a singlecolumn gas chromatography analysis of an unknown sample isrisky. In such cases, multiple and different analytical tech-niques must be used for absolutely positive identification, forexample, several di
5、fferent gas chromatography columns, gaschromatography/mass spectrometer, or gas chromatography/infrared, etc. In these test methods the material is known and isclearly defined.1.3 Oxygenated compounds, if present, may interfere andcause erroneous results. Such oxygenated compounds are notnormally pr
6、esent in mineral spirits.1.4 Three test methods are covered as follows:1.4.1 Test Method A, measurement of ethylbenzene content,C8plus higher aromatics (except ethylbenzene), and totalaromatics by means of a single packed column gas chromato-graphic analysis.1.4.2 Test Method B, measurement of ethyl
7、benzene contentby means of a rapid packed column gas chromatographicanalysis.1.4.3 Test Method C, measurement of ethylbenzene content,C8plus higher aromatics (except ethylbenzene) and totalaromatics by means of a capillary column gas chromatographicanalysis.1.5 The values stated in SI units are to b
8、e regarded as thestandard. The values given in parentheses are for informationonly.1.6 For purposes of determining conformance of an ob-served or a calculated value using this test method to relevantspecifications, test result(s) shall be rounded off “to the nearestunit” in the last right-hand digit
9、 used in expressing thespecification limit, in accordance with the rounding-off methodof Practice E29.1.7 For hazard information and guidance, see the suppliersMaterial Safety Data Sheet.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is t
10、heresponsibility 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.2. Referenced Documents2.1 ASTM Standards:2D86 Test Method for Distillation of Petroleum Products atAtmospheric PressureE29 Prac
11、tice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals (Withdrawn 2009)3E260 Practice for Packed Column Gas Chromatography2.2 ASTM Adjuncts:D2
12、PP Determination of Precision and Bias Data43. Summary of Test Methods3.1 The material, with an internal standard, is introducedinto a gas chromatographic column containing a strongly polarliquid phase. The polar phase has very little affinity forsaturated and olefinic hydrocarbons while exhibiting
13、a pro-nounced retention of aromatics. This selectivity, which isillustrated in Fig. 1, results in the elution of all saturated and1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcomm
14、ittee D01.35 on Solvents, Plasticizers, and ChemicalIntermediates.Current edition approved June 1, 2012. Published August 2012. Originallyapproved in 1973. Last previous edition approved in 2006 as D3257 06. DOI:10.1520/D3257-06R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org
15、, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from ASTM International Headquarte
16、rs. Order Adjunct No.ADJD6300.*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 States1olefinic hydrocarbons in the products described above prior tothe elution of toluene. Eithe
17、r a thermal conductivity or flameionization detector may be used. Calibration is obtained in TestMethod A and C from a synthetic blend of the most importantaromatic compounds. Internal standards are used in all threetest methods. Typical chromatograms are shown in Fig. 2 andFig. 3.NOTE 1Refer to Pra
18、ctice E260 for additional information on gaschromatography techniques.4. Significance and Use4.1 These test methods were developed to measure the typesand amounts of aromatics in mineral spirits to determinecompliance with air pollution regulations that restrict thearomatic content of solvents. They
19、 have been demonstrated toFIG. 1 Typical Resolution of Test Blend Using Packed ColumnFIG. 2 Typical Packed Column Chromatogram of Mineral Spirits (Column and Conditions Described in Table 2)FIG. 3 Typical Capillary Chromatogram of Mineral Spirits (Col-umn and Conditions Described in Table 3)D3257 06
20、 (2012)2be workable and to produce accurate results. However, due tothe sensitivity of the tests to operating variables, some labora-tories having limited experience with gas chromatographicanalyses of hydrocarbons may experience difficulty in perform-ing the tests.TEST METHOD AETHYLBENZENE AND TOTA
21、LAROMATICS CONTENTS BY MEANS OF A SINGLEPACKED COLUMN GAS CHROMATOGRAPHICANALYSIS5. Apparatus5.1 Chromatograph, any gas chromatographic instrumentthat has the following performance and characteristics:5.1.1 SensitivityThe overall sensitivity must be sufficientto detect 0.1 volume % of any aromatic c
22、ompound of interestwith a peak height of at least 10 % of full-scale chart deflectionwithout loss of resolution as defined in 5.1.2, or 10 times thenoise level.5.1.2 ColumnAny column and conditions may be usedprovided the system meets all the following criteria when thetest blend is injected into th
23、e chromatograph and the chromato-gram recorded in accordance with 7.2, is analyzed as follows:5.1.2.1 Construct tangents to the peak to intersect thebaseline for the n-tridecane (nC13) and toluene peaks. Measurethe distance between the two peaks and the width of each peakas the distance along the ba
24、seline under the peak between thepoints of intersection (see Fig. 1).5.1.2.2 Calculate the peak resolution,R 5 2Dd/Y11Y2!(1)where:Dd = distance between nC13and toluene peaks,Y1= width of nC13peak along the baseline, andY2= width of the toluene peak along the baseline.The peak resolution, R, must be
25、not less than 0.9, otherwisethe resolution of ethylbenzene may be lost.NOTE 2The selectivity of the column (separation of the nonaromaticsfrom aromatics) can be increased by increasing the concentration of liquidphase or by increasing the temperature of the chromatographic column.The resolution of t
26、he aromatic compounds can be improved by increasingthe length of the column or by decreasing the oven temperature or inletpressure of the carrier gas.5.1.2.3 Ethylbenzene must be separated from paraxyleneand isopropylbenzene or from paraxylene plus isopropylben-zene with the depth of the valley afte
27、r ethylbenzene not lessthan 50 % of the ethylbenzene peak height.5.1.2.4 The system must measure durene with a peak heightof at least 10 % of full scale chart deflection or at least 10 timesthe noise level.NOTE 3A combination of column materials and conditions that hasbeen found to be particularly s
28、uitable for this test method is listed in Table1. Such column may be obtained from most chromatography supplyhouses that offer packed GC columns.5.2 Strip Chart Recorder IntegratorA recording potenti-ometer with a fullscale deflection of 10 mV or less should beused. If manual integration, such as tr
29、iangulation, paper cut-outor planimeter, is employed the chart speed should be at least1.5 m/h (60 in./h) in order to minimize errors in peak areameasurement. This is not necessary where a ball-and-disk or anelectronic integrator is employed.5.3 Electronic IntegrationAny electronic data processingsy
30、stem or integration device, or both, may be used to determinethe areas of the chromatographic peaks.5.4 Micro SyringeA 10-L micro syringe for specimenintroduction.6. Reagents and Materials6.1 Aromatic HydrocarbonsToluene, ethylbenzene, par-axylene, isopropylbenzene (cumene), 1,2,4-trimethylbenzene(p
31、seudocumene), and 1,2,4,5-tetramethylbenzene (durene)99.5 mol % minimum.6.2 Carrier Gas (Note 3).6.3 Internal StandardCyclohexanone, 99.5 mol % mini-mum (see 1.7).6.4 Chromatographic Column (Note 3).6.5 Normal ParaffnnTridecane, 99.5 mol % minimum.6.6 Solid Support (Note 3).6.7 Paraffn Solvent for T
32、est Blendn-Hexane, n-heptane,or iso-octane 99 mol % minimum.7. Calibration7.1 Preparation of Test BlendPrepare a test blend toevaluate the sensitivity and resolution of the equipment and testprocedure. To do this, pipet the exact volume of each hydro-carbon indicated in Table 2 into a 100-mLvolumetr
33、ic flask. Fillto the 100-mL mark with one of the solvents listed in 6.7 andmix by inverting several times. See 1.7.NOTE 4Durene is a solid. In preparing the test blend, the quantity ofdurene required should be weighed, using as its density 0.8875 g/mL.TABLE 1 Typical Column and ConditionsLength, m 3
34、.7 (12 ft)Diameter, mm:Inside .Outside 3.2 (18 in.)Liquid phase CEFAWeight % liquid 25Solid support: calcined pink, diatomaceous silicaBMesh 80100Treatment noneInlet, C 250Detector, C 250Column, C 110Carrier gas heliumInlet pressure, KPa 550 (80 psi)Flow rate, mL/min 35Detector flame ionizationRecor
35、der, mV 1Specimen, L 2Sample split (30 to 1)AN,N-bis (2-cyanoethyl) formamide.BThe sole source of supply of the material Chromosorb-P known to the committeeat this time is Celite Corp. If you are aware of alternative suppliers, please providethis information to ASTM International Headquarters. Your
36、comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D3257 06 (2012)37.2 Select the instrument conditions and specimen size so asto give the necessary sensitivity and resolution. Inject the testblend into the column at these conditions.
37、Change the attenu-ation, if necessary, so that the internal standard and aromaticpeaks are measured with a chart deflection of not less than25 % nor more than 95 % of full scale for attenuated peaks.Check the column performance against the requirements givenin 5.1.2.7.3 Response FactorAssume that th
38、e aromatics in thesample have the same relative response as pseudocumene inthe test blend. Using the results from the test blend, calculatethe response factor as follows:r 5AISVIS3VaAa(2)where:r = relative response factor for aromatics,AIS= area of the internal standard peak in arbitrary unitscorrec
39、ted for attenuation,VIS= volume % of the internal standard in the blend,Aa= area of the pseudocumene peak in arbitrary unitscorrected for attenuation, andVa= volume % of pseudocumene in the blend.8. Procedure8.1 Using the exact instrument conditions as were used inthe calibration, inject the test ma
40、terial. Inspect the chromato-gram to determine that there is complete resolution between thesaturated and the aromatic peaks.8.2 Pipet exactly 1.0 mLof cyclohexanone internal standardinto a 10-mL volumetric flask. Fill to the mark with the sampleand mix by inverting several times.8.3 With the exact
41、instrumental conditions used in thecalibration, inject the same volume of sample containing theinternal standard. Change the attenuation, if necessary, so as tomeasure the area of the internal standard and aromatic peakswith not less than 25 % nor more than 95 % chart deflection onattenuated peaks.9
42、. Calculation9.1 Measure the areas of all aromatic and internal standardpeaks. Use of an electronic integrator is recommended toobtain the best accuracy and precision.NOTE 5Because the C8and heavier aromatic compounds may not becompletely resolved, peak height multiplied by one half width or retenti
43、ontime must not be used as a means of measuring the area.9.2 If a different attenuation is used for part of the chro-matogram, correct to a constant attenuation basis by multiply-ing the area of the aromatic peaks by the ratio:Sa/Ss(3)where:Ss= attenuation sensitivity used for the internal standardp
44、eak andSa= attenuation sensitivity used for the aromatic peak.9.3 Calculate the concentrations of ethylbenzene and C8andheavier aromatics as follows:Va5 Aa3 r 310!/AIS30.9! (4)5AaAIS3 r 311.11where:Va= volume % of the aromatic compound(s),Aa= area of the aromatic peak(s) corrected to a constantatten
45、uation,r = relative response factor for the aromatic compounds,10 = volume % of internal standard,AIS= area of the internal standard peak, and0.9 = factor to correct for the dilution by the internalstandard.9.4 Total AromaticsAdd the amounts of the aromaticcompounds found to obtain the volume percen
46、t of totalaromatics in the sample.10. Report10.1 Report the following information: concentrations ofethylbenzene, total aromatics, and C8plus higher aromatics(except ethylbenzene) in volume percent to the nearest 0.1 %.11. Precision and Bias511.1 The precision estimates are based on an interlaborato
47、rystudy on four samples, containing approximately 6.5, 8.5, 11.8,and 16.5 % total aromatics and 0.0, 1.0, 4.0, and 0.3 %ethylbenzene. One analyst in each of six laboratories per-formed duplicate determinations on different days, for a total of48 determinations of total aromatics content and 48 deter
48、mi-nations of ethylbenzene content. The within-laboratory coeffi-cient of variation was found to be 1.7 % relative with 23 df,and the between-laboratories coefficient of variation was 4.4 %relative with 5 df. Based on these coefficients the followingcriteria should be used for judging the acceptabil
49、ity of resultsat the 95 % confidence level.11.1.1 RepeatabilityTwo results obtained by the sameoperator on different days should be considered suspect if theydiffer by more than 5 % relative.11.1.2 ReproducibilityTwo results obtained by operatorsin different laboratories should be considered suspect if theydiffer by more than 16 % relative.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1015.TABLE 2 Composition of Test BlendVolume, mLNormal tridecane from 6.5 1Toluene 2E
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