1、Designation: D3606 10Standard Test Method forDetermination of Benzene and Toluene in Finished Motorand Aviation Gasoline by Gas Chromatography1This standard is issued under the fixed designation D3606; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 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 benzeneand toluene in finished motor and
3、aviation gasolines by gaschromatography.1.2 Benzene can be determined between the levels of 0.1and 5 volume % and toluene can be determined between thelevels of 2 and 20 volume %.1.3 The precision for this test method was determined usingconventional gasoline as well as gasolines containing oxygen-a
4、tes (ethers such as methyl tert-butyl ether, ethyl tert-butylether and tert-amyl methyl ether).1.4 Methanol may cause interference. Appendix X1 pro-vides an option for modifying the test method for analyzingsamples containing ethanol.1.5 The values stated in SI units are to be regarded asstandard. T
5、he values given in parentheses are for informationonly.1.6 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
6、 of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsE694 Specification for Laboratory Glass Volumetric Appa-ratusE969 Specification for Glass Volumetric (Transfer) PipetsE1044 Specification for Glass
7、Serological Pipets (GeneralPurpose and Kahn)E1293 Specification for Glass Measuring Pipets3. Summary of Test Method3.1 An internal standard, methyl ethyl ketone (MEK), isadded to the sample which is then introduced into a gaschromatograph equipped with two columns connected inseries. The sample pass
8、es first through a column packed with anonpolar phase such as dimethylpolysiloxane (8.1.1) whichseparates the components according to boiling point. Afteroctane has eluted, the flow through the nonpolar column isreversed, flushing out the components heavier than octane. Theoctane and lighter compone
9、nts then pass through a columnpacked with a highly polar phase such as 1, 2, 3-tris(2-cyanoethoxy) propane (8.1.2) which separates the aromatic andnonaromatic compounds. The eluted components are detectedby a thermal conductivity detector. The detector response isrecorded, the peak areas are measure
10、d, and the concentration ofeach component is calculated with reference to the internalstandard.4. Significance and Use4.1 Benzene is classed as a toxic material. A knowledge ofthe concentration of this compound can be an aid in evaluatingthe possible health hazard to persons handling and using thega
11、soline. This test method is not intended to evaluate suchhazards.5. Apparatus5.1 ChromatographAny chromatographic instrument thathas a backflush system and thermal conductivity detector, andthat can be operated at the conditions given in Table 1, can beemployed. Two backflush systems are shown. Fig.
12、 1 is apressure system and Fig. 2 is a switching valve system. Eitherone can be used.5.2 Columns:5.2.1 Column AOne 0.8 m (2.5 ft) by 3.2 mm (18 in.)outside diameter stainless steel column packed with 10 mass %dimethylpolysiloxane (for example, OV-101) on ChromosorbW, 60 to 80 mesh.1This test method
13、is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0L on Gas Chromatography Methods.Current edition approved Oct. 1, 2010. Published November 2010. Originallyapproved in 1977. Last previous edition approved in 20
14、07 as D360607. DOI:10.1520/D3606-10.2For 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 website.1*A Summary of Changes se
15、ction appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2.2 Column BOne 4.6 m (15 ft) by 3.2 mm outsidediameter stainless steel column packed with 20 mass % TCEPon Chromosorb P, 80 to 100 mesh.5.3 R
16、ecordera strip chart recorder. An electronic integrat-ing device or a computer capable of graphical presentation ofthe chromatogram. The electronic integrating device or com-puter must be capable of measuring 0.1 volume % MEK withsatisfactory signal-to-noise. If a strip chart recorder is to beused,a
17、0to1mVrange recording potentiometer with aresponse time of 2 s or less and a maximum noise level of 60.3% of full scale is recommended. The detector strip chartrecorder combination must producea4mmdeflection for a 2L sample containing 0.1 volume % MEK when operated atmaximum sensitivity.5.4 Microsyr
18、inge 5 L capacity.5.5 Volumetric Pipets, Class A0.5, 1, 5, 10, 15, and 20 mLcapacities (see Specification E694 and E969).5.6 Measuring Pipets1 and 2mL capacities calibrated in0.01 mL; 5mL calibrated in 0.1mL, for use in dispensingvolumes of benzene and toluene not covered by the volumetricpipets (se
19、e Specification E1044 and E1293) during preparationof standard samples (see 11.1).NOTE 1Other volume dispensing equipment capable of delivering thespecified volumes within the stated tolerance limits may be used as analternative to the requirements stated in 5.5 and 5.6.5.7 Flasksvolumetric, 25 and
20、100 mL capacity.5.8 Vibratorelectric.5.9 Vacuum Source.5.10 Evaporatorvacuum, rotary.5.11 Flaskboiling, round-bottom, short-neck, with2440standard taper joint, 500 mL capacity. Suitable for use withevaporator (5.10).5.12 Lampinfrared.5.13 Buretsautomatic, with integral reservoir, 25 mLcapacity.6. Ma
21、terials6.1 Carrier GasHelium, 99.99 % pure. (WarningCompressed gas under high pressure.)6.2 SupportCrushed firebrick, acid-washed, 60 to 80-mesh and 80 to 100-mesh.6.3 Liquid Phases1, 2, 3-Tris(2-cyanoethoxy) propane(TCEP) and methyl silicone.36.4 Solvents:6.4.1 Methanolreagent grade. (WarningFlamma
22、ble.Vapor harmful. Can be fatal or cause blindness if swallowed orinhaled.)6.4.2 Chloroformreagent grade. (WarningCan be fatalif swallowed. Harmful if inhaled.)6.4.3 Methylene Chloridefor cleaning columns.(WarningHarmful if inhaled. High concentrations can causeunconsciousness or death.)6.4.4 Aceton
23、e for cleaning columns. (WarningExtremely flammable. Vapors can cause flash fires.)6.5 Internal Standard:6.5.1 Methyl Ethyl Ketone (MEK)99.5% minimum purity.(WarningFlammable. Vapor can be harmful.)6.6 Calibration Standards6.6.1 Benzene99+mol %. (WarningPoison. Carcino-gen. Harmful or fatal if swall
24、owed. Extremely flammable.Vapors can cause flash fires.)6.6.2 Isooctane (2,2,4trimethyl pentane)99+mol %.(WarningExtremely flammable. Harmful if inhaled.)6.6.3 Toluene(WarningFlammable. Vapor harmful.)6.6.4 n-Nonane99+mol %. (WarningFlammable. Va-por harmful.)7. Sampling7.1 Gasoline(WarningExtremely
25、 flammable. Vaporsharmful if inhaled.) Samples to be analyzed by this test methodshall be obtained using the procedures outlined in PracticeD4057.8. Preparation of Column Packings8.1 Prepare two packing materials (one packing materialconsists of 10 mass % dimethylpolysiloxane on ChromosorbW; the oth
26、er, 20 mass % TCEP on Chromosorb P) in accor-dance with the following procedures:8.1.1 Dimethylpolysiloxane PackingWeigh 45 g of theChromosorb W, 60 to 80 mesh and pour into the 500 mL flask(5.11). Dissolve5gofthedimethylpolysiloxane in approxi-mately 50 mL of chloroform. (WarningCan be fatal ifswal
27、lowed. Harmful if inhaled.) Pour the methyl silicone-chloroform solution into the flask containing the ChromosorbW. Attach the flask to the evaporator (5.10), connect thevacuum, and start the motor. Turn on the infrared lamp andallow the packing to mix thoroughly until dry.8.1.2 1, 2, 3-Tris(2-cyano
28、ethoxy) Propane (TCEP)PackingWeigh 80 g of Chromosorb P, 80 to 100 mesh andpour into the 500 mL flask (5.11). Dissolve 20 g of TCEP in3Packed column liquid phases such as OV 101 are considered to be of thedimethylpolysiloxane type. Other equivalent phases can also be used. Consult withthe column man
29、ufacturer or phase supplier for information.TABLE 1 Instrument ParametersDetector thermal conductivityColumns: two, stainless steelLength, m (A) 0.8; (B) 4.6Outside diameter, mm 3.2Stationary phase (A) dimethylpolysiloxane, 10 mass %(B) TCEP, 20 mass %Support (A) Chromosorb W, 60 to 80-mesh(B) Chrom
30、osorb P, 80 to 100-meshReference column Any column or restriction may beused.Temperature:Sample inlet system, C 200Detector, C 200Column, C 145Carrier Gas: heliumLinear Gas Rate, cm/s 6Volume flow rate, cm3/min approximately 30Column head pressure, kPa (psi) approximately 200 (30)Recorder range, mV
31、0 to 1Chart speed, cm/min 1Sample size, L 2Total cycle time, min 8Backflush, min approximately 0.75AAThis back flush time must be determined for each column system.D3606 102200 mL of methanol and pour into the flask containing theChromosorb P. Attach the flask to the evaporator (5.10),connect the va
32、cuum, and start the motor. Turn on the infraredlamp and allow the packing to mix thoroughly until dry. (Donot heat the packing over 180C.)9. Preparation of Column9.1 Cleaning ColumnClean the stainless steel tubing asfollows. Attach a metal funnel to one end of the steel tubing.Hold or mount the stai
33、nless steel tubing in an upright positionand place a drain beaker under the outlet end of the tubing.Pour about 50 mL of methylene chloride (WarningHarmfulif inhaled. High concentrations can cause unconsciousness ordeath) into the funnel and allow it to drain through the steeltubing and into the dra
34、in beaker. Repeat the washing procedurewith 50 mL of acetone. (WarningHarmful if inhaled. Highconcentrations can cause unconsciousness or death.) RemoveFIG. 1 Pressure BackflushD3606 103the funnel and attach the steel tubing to an air line, using vinyltubing to make the connection. Remove all solven
35、t from thesteel tubing by blowing filtered, oil-free air through or pullinga vacuum.9.2 Packing ColumnsPreform Columns A and B sepa-rately to fit the chromatograph. Pack the 0.8 m tubing (ColumnA) with the dimethylpolysiloxane packing (8.1.1) and the 4.6m tubing (Column B) with the TCEP packing (8.1
36、.2) using thefollowing procedure. Close one end of each tubing with asmall, glass wool plug, and connect this end to a vacuumsource by means of a glass wool-packed tube. To the other endconnect a small polyethylene funnel by means of a short lengthof vinyl tubing. Start the vacuum and pour the appro
37、priatepacking into the funnel until the column is full. While fillingeach column, vibrate the column with the electric vibrator tosettle the packing. Remove the funnel and shut off the vacuumsource. Remove the top 6 mm (14 in.) of packing and insert aglass wool plug in this end of the column.FIG. 2
38、Valve BackflushD3606 10410. Configuration of Apparatus and Establishment ofConditions10.1 Conditioning ColumnInstall Columns A and B asshown in Fig. 1 or Fig. 2 in accordance with the systempreferred (5.1). Do not connect the exit end of Column B to thedetector until the columns have been conditione
39、d. Pass heliumgas through the column at approximately 40 cm3/min. Condi-tion the column at the listed temperatures for the specified timeperiods.Temperature, C Hours at Temperature501210012150 1170 310.2 AssemblyConnect the outlet of Column B to thedetector port. Adjust the operating conditions to t
40、hose listed inTable 1, but do not turn on the detector circuits. Check thesystems for leaks.10.3 Flow Rate Adjustment:10.3.1 Column System Setup for Pressure Backflushing(Fig. 1):10.3.1.1 Open Tap A and B and close C; set the primarypressure regulator to give the desired flow (Table 1) throughthe co
41、lumn system (at an approximate gage pressure of 205kPa (30 psi). Measure the flow rate at the detector vent,sample side. Observe the pressure on gage GC.10.3.1.2 Close Tap A and open B and C. The pressurereading on gage GAshould fall to zero immediately. If not,open the needle valve until the pressu
42、re falls to zero.10.3.1.3 Close Tap B. Adjust the secondary pressure regu-lator until the reading of gage GCis 3.5 to 7 kPa (0.5 to 1 psi)higher than observed in 10.3.1.1.10.3.1.4 Open Tap B and adjust the backflush vent controlneedle valve until the pressure recorded on GAapproximates agage pressur
43、e of 14 to 28 kPa (2 to 4 psi).10.3.1.5 Forward FlowOpen Taps A and C and close TapB (Fig. 1 B1).10.3.1.6 BackflushClose Tap A and open Tap B. (Thereshould be no baseline shift on switching from forward flow tobackflush. If there is a baseline shift increase the secondarypressure slightly.) (Fig. 1)
44、10.3.2 Column System Setup for Valve Backflushing (Fig.2):10.3.2.1 Set the valve in the forward flow mode (Fig. 2 B1),and adjust flow control A to give the desired flow (Table 1).Measure the flow rate at the detector vent, sample side.10.3.2.2 Set the valve in the backflush position (Fig. 2 B2),meas
45、ure the flow rate at the detector vent, sample side. If theflow has changed, adjust flow control B to obtain the correctflow. (Flows should match to within 61cm3/min).10.3.2.3 Change the valve from forward flow to the back-flush position several times and observe the baseline. Thereshould be no base
46、line shift or drift after the initial valve kickthat results from the pressure surge. If there is a baseline shift,increase or decrease flow control B slightly to balance thebaseline. (A persistent drift could indicate leaks somewhere inthe system.)10.4 Determine Time to BackflushThe time to backflu
47、shwill vary for each column system and must be determinedexperimentally as follows. Prepare a mixture of 5 volume %isooctane in n-nonane. Using the injection technique describedin 11.4 and with the preferred system (10.3)intheforward flowmode, inject 1 L of the isooctane n-nonane mixture. Allowthe c
48、hromatogram to run until the n-nonane has eluted and thedetector signal has returned to baseline. Measure the time inseconds, from the injection until the detector signal returns tobaseline between the isooctane and n-nonane peaks. At thispoint all of the isooctane, but essentially none of the n-non
49、ane,should have eluted. One half of the time determined shouldapproximate the “time to backflush” and should be from 30 to60 s. Repeat the run, including the injection, but switching thesystem to the backflush mode at the predetermined “time tobackflush.” This should result in a chromatogram of isooctanewith little or no n-nonane visible. If necessary, make additionalruns, adjusting the “time to backflush” until this condition ofall the isooctane and little or no n-nonane is attained. The “timeto backflush” s
