1、Designation: D5917 09 D5917 12Standard Test Method forTrace Impurities in Monocyclic Aromatic Hydrocarbons byGas Chromatography and External Calibration1This standard is issued under the fixed designation D5917; 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 () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of the total nonaromatic hydrocarb
3、ons and trace monocyclic aromatichydrocarbons in toluene, mixed xylenes, and p-xylenes-xylene by gas chromatography. The purity of toluene, mixed xylenes, orp-xylenes-xylene can also be calculated. Calibration of the gas chromatographic system is done by the external standard calibrationtechnique. A
4、 similar test method, using the internal standard calibration technique, is Test Method D2360.1.2 Total aliphatic hydrocarbons containing 1 through 10 carbon atoms (methane through decanes) can be detected by this testmethod at concentrations ranging from 0.001 to 2.500 weight %.1.2.1 A small amount
5、 of benzene in mixed xylenes or p-xylenes may not be distinguished from the nonaromatics and theconcentrations are determined as a composite (see 6.1).1.3 Monocyclic aromatic hydrocarbon impurities containing 6 through 10 carbon atoms (benzene through C 10 aromatics) canbe detected by this test meth
6、od at individual concentrations ranging from 0.001 to 1.000 weight %.1.4 In determining the conformance of the test results to applicable specifications, results shall be rounded off in accordancewith the rounding-off method of Practice E29.1.5 The values stated in SI units are to be regarded as sta
7、ndard. No other units of measurement are included in this standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the ap
8、plicability of regulatorylimitations prior to use. For specific hazard statement, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D841 Specification for Nitration Grade TolueneD2306 Test Method for C8 Aromatic Hydrocarbon Analysis by Gas Chromatography (Withdrawn 2006)3D2360 Test Method for
9、 Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas ChromatographyD3437 Practice for Sampling and Handling Liquid Cyclic ProductsD4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density MeterD4307 Practice for Preparation of Liquid Blends for Use as Ana
10、lytical StandardsD4790 Terminology of Aromatic Hydrocarbons and Related ChemicalsD5136 Specification for High Purity p-XyleneD5211 Specification for Xylenes for p-Xylene FeedstockD6526 Test Method for Analysis of Toluene by Capillary Column Gas ChromatographyD6563 Test Method for Benzene, Toluene, X
11、ylene (BTX) Concentrates Analysis by Gas ChromatographyD6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related MaterialsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE260 Practice for Packed Column Ga
12、s ChromatographyE355 Practice for Gas Chromatography Terms and Relationships1 This test method is under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of SubcommitteeD16.01 on Benzene, Toluene, Xylenes, Cyclohexane and Their Der
13、ivatives.Current edition approved Jan. 1, 2009Sept. 15, 2012. Published January 2009September 2102. Originally approved in 1996. Last previous edition approved in 20022009as D5917 02.D5917 09. DOI: 10.1520/D5917-09.10.1520/D5917-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.or
14、g, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what chang
15、es have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the offici
16、al document.*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 States1E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1510 Practi
17、ce for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs2.2 Other Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.120033. Terminology3.1 See Terminology D4790 for definitions of terms used in this test method.3.2 Mixed xylenes are a mixture of C8 aromatics
18、including m-xylene, o-xylene, and p-xylene. Industry convention includesethylbenzene as a mixed xylene though ethylbenzene is not technically a xylene. Styrene is excluded.4. Summary of Test Method4.1 A repeatable volume of the specimen to be analyzed is precisely injected into a gas chromatograph e
19、quipped with a flameionization detector (FID). The peak area of each impurity is measured. Concentration of each impurity is determined from thelinear calibration curve of peak area versus concentration. Purity by gas chromatography (GC) is calculated by subtracting the sumof the impurities found fr
20、om 100.00. Results are reported in weight percent.5. Significance and Use5.1 Determining the type and amount of hydrocarbon impurities remaining from the manufacture of toluene, mixed xylenes, andp-xylenes used as chemical intermediates and solvents is often required. This test method is suitable fo
21、r setting specifications andfor use as an internal quality control tool where these products are produced or are used. Typical impurities are: alkanes containing1 to 10 carbons atoms, benzene, toluene, ethylbenzene (EB), xylenes, and aromatic hydrocarbons containing nine carbon atoms.5.1.1 Refer to
22、Test Method D2306 for determining the C8 aromatic hydrocarbon distribution in mixed xylenes.5.2 Purity is commonly reported by subtracting the determined expected impurities from 100.00. However, a gas chromato-graphic analysis cannot determine absolute purity if unknown or undetected components are
23、 contained within the material beingexamined.5.3 This test method is similar to Test Method D2360, however, interlaboratory testing has indicated a bias may exist betweenthe two methods. Therefore the user is cautioned that the two methods may not give comparable results.6. Interferences6.1 In some
24、cases for mixed xylenes and p-xylene, it may be difficult to resolve benzene from the nonaromatic hydrocarbons.Therefore the concentrations are determined as a composite. In the event that the benzene concentration must be determined, analternate method such as Test Method D6526 must be selected to
25、ensure an accurate assessment of the benzene concentration.6.2 Complete separation of ethylbenzene and m-xylene from p-xylene is difficult and can be considered adequate if the distancefrom baseline to valley between peaks is not greater than 50 % of the peak height of the impurity.7. Apparatus7.1 G
26、as ChromatographAny instrument having a flame ionization detector that can be operated at the conditions given inTable 1. The system shall have sufficient sensitivity to obtain a minimum peak height response for 0.001 weight % impurity oftwice the height of the background noise.7.2 ColumnsThe choice
27、 of column is based on resolution requirements. Any column may be used that is capable of resolvingall significant impurities from the major component. The column and conditions described in Table 1 have been used successfullyand shall be used as a referee in cases of dispute.7.3 RecorderElectronic
28、integration is recommended.7.4 InjectorThe specimen must be precisely and repeatably injected into the gas chromatograph. An automatic sampleinjection device is highly recommended although manual injection can be employed if the criteria in 12.7 can be satisfied.7.5 Volumetric Flask, 100-mL capacity
29、.7.6 Syringe, 100 L.3 Available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.D5917 1228. Reagents8.1 Purity of ReagentReagent grade chemicals shall be used in all tests. Unless otherwise indic
30、ated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society,4 wheresuch specifications are available.8.2 Carrier GasChromatographic grade helium or hydrogen, 99.999 % is recommended. Purify carrier, makeupfuel and
31、detector gases to remove makeup gases by adding traps to reduce the concentration of any remaining oxygen, water, andhydrocarbons. Purify air by adding traps to reduce the concentration of any remaining hydrocarbons and water.8.3 Air, Chromatographic grade, containing less than 0.1 ppm THC.8.4 High
32、Purity p-Xylene, 99.999 weight % or greater purity.8.4.1 Most p-xylene is available commercially at a purity less than 99.9 % and can be purified by recrystallization. To prepare1.9 L of high purity p-xylene, begin with approximately 3.8 L of material and cool in a flammable storage freezer at 10 10
33、 65C until approximately 12 to 34 of the p-xylene has frozen. This should require about 5 h. Remove the sample and decant the liquidportion. The solid portion is the purified p-xylene. Allow the p-xylene to thaw and repeat the crystallization procedure on theremaining sample until the p-xylene is fr
34、ee of contamination as indicated by gas chromatography.8.5 Pure compounds for calibration, shall include n-nonane, benzene, toluene, ethylbenzene, o-xylene, m-xylene, and cumene.If applicable, the calibration may include paradiethylbenzene (PDEB). The purity of all reagents should be 99 weight %. If
35、 thepurity is less than 99 %, the concentration and identification of impurities must be known so that the composition of the standardcan be adjusted for the presence of the impurities.9. Hazards9.1 Consult current OSHA regulations, suppliers Material Safety Data Sheets, and local regulations for al
36、l materials used inthis test method.10. Sampling10.1 Sample the material in accordance with Practice D3437.11. Preparation of Apparatus11.1 Follow manufacturers instructions for mounting and conditioning the column into the chromatograph and adjusting theinstrument to the conditions described in Tab
37、le 1, allowing sufficient time for the equipment to reach equilibrium. See PracticesE260, E355, and E1510 for additional information on gas chromatography practices and terminology.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestio
38、ns on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.TABLE 1 Typical Method Parameter
39、s Recommended OperatingConditionsInlet SplitTemperature, C 270Column:Tubing fused silicaLength, m 60Internal diameter, mm 0.32Stationary phase crosslinked polyethylene glycolFilm thickness, m 0.25Column temperature programInitial temperature, C 60Initial time, min 10Programming rate, C/min 5Final, C
40、 150Time 2, min 10Carrier gas Helium or HydrogenLinear velocity, cm/s at 145C 20 Helium or 45 HydrogenSplit ratio 100:1Sample size, L 1.0Detector: flame ionizationTemperature, C 300Analysis time, min 30D5917 12312. Calibration12.1 Prepare a synthetic mixture of high purity p-xylene containing impuri
41、ties at concentrations representative of those expectedin the samples to be analyzed. The volume of each hydrocarbon impurity must be measured to the nearest 1 L and all liquidreference compounds must be brought to the same temperature before mixing. Refer to Table 2 for an example of a calibrationb
42、lend. n-Nonane will represent the nonaromatic fraction, o-xylene the o-xylene fraction, m-xylene the m-xylene fraction. Cumenewill represent the aromatic hydrocarbons containing nine carbon atoms or greater, with exception of PDEB. If PDEB is includedin the calibration, PDEB will represent PDEB.12.1
43、.1 Prior to preparing the calibration standard, all reference compounds and any samples to be analyzed must be brought tothe same temperature, preferably 25C.ambient or 20C.12.2 Using the exact volumes and densities in Table 2, calculate the weight % concentration for each impurity in the calibratio
44、nblend as follows:Ci 5100 DiVi/VtDp! (1)where:where:Di = density of impurity i from Table 2,Vi = volume of impurity i , mL,Vi = volume of impurity i, mL,Dp = density of p-xylene from Table 2,Vt = total volume of standard blend, mL, andCi = concentration of impurity i, weight %.12.2.1 Alternatively,
45、calibration standards may be used that have been gravimetrically prepared in accordance with PracticeD4307.12.3 Inject the resulting solution from 12.1 into the chromatograph, collect and process the data. A typical chromatogram isillustrated in Fig. 1.12.4 Determine the response factor for each imp
46、urity in the calibration mixture as follows:RFi 5Ci/Ai (2)where:where:RFi = response factor for impurity i,Ai = peak area of impurity i, andCi = concentration of impurity i, as calculated in 12.2, weight %.12.5 Analyze the calibration solution(s) a minimum of three times and calculate an average RF.
47、12.6 Determine the sample standard deviation for RF of each impurity using a scientific calculator or spreadsheet program.Determine the coefficient of variation for each RF as follows:TABLE 2 Preparation of Calibration BlendCompound DensityA RecommendedVol, LResulting Concentration(including PDEB)Re
48、sulting Concentration(excluding PDEB)Volume % Weight % Volume % Weight %p-Xylene 0.857 99.60-99.62 ml 99.60 99.60 99.62 99.62p-Xylene 0.861 99.60-99.62 ml 99.60 99.60 99.62 99.62Benzene 0.874 20 0.020 0.020 0.020 0.020Benzene 0.879 20 0.020 0.020 0.020 0.020Toluene 0.862 20 0.020 0.020 0.020 0.020To
49、luene 0.867 20 0.020 0.020 0.020 0.020Ethylbenzene 0.863 100 0.100 0.100 0.100 0.100Ethylbenzene 0.867 100 0.100 0.100 0.100 0.100o-Xylene 0.876 100 0.100 0.102 0.100 0.102o-Xylene 0.880 100 0.100 0.102 0.100 0.102Cumene 0.857 20 0.020 0.020 0.020 0.020Cumene 0.862 20 0.020 0.020 0.020 0.020n-Nonane 0.714 20 0.020 0.017 0.020 0.017n-Nonane 0.718 20 0.020 0.017 0.020 0.017m-Xylene 0.864 100 0.100 0.101 0.100 0.101PDEB 0.862 20 0.020 0.020 n/a n/aPDEB 0.866 20 0.020 0.020 n/a n/aA Density at 25C.20C. Values obtained from “Physical Constants of Hy
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