1、Designation: D3606 101Standard 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 th
2、e 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.1NOTESubsection 1.3 and Note 7 were corrected editorially in April 2016.1. Scope*1.1 This test met
3、hod covers the determination of benzeneand toluene in finished motor and 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 deter
4、mined usingconventional gasoline as well as gasolines containing oxygen-ates (ethers such as methyl tert-butyl ether, ethyl tert-butylether,tert-amyl methyl ether, and ethanol).1.4 Methanol may cause interference. Appendix X1 pro-vides an option for modifying the test method for analyzingsamples con
5、taining ethanol.1.5 The values stated in SI units are to be regarded asstandard. The 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 e
6、stablish appro-priate safety and health practices and determine the applica-bility 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
7、Specification for Glass Volumetric (Transfer) PipetsE1044 Specification for Glass 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 int
8、o a gaschromatograph equipped with two columns connected inseries. The sample passes 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 isrevers
9、ed, flushing out the components heavier than octane. Theoctane and lighter components 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 c
10、onductivity detector. The detector response isrecorded, the peak areas are measured, 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
11、an aid in evaluatingthe possible health hazard to persons handling and using thegasoline. 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
12、conditions given in Table 1, can beemployed. Two backflush systems are shown. Fig. 1 is apressure system and Fig. 2 is a switching valve system. Eitherone can be used.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direc
13、t responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved Oct. 1, 2010. Published November 2010. Originallyapproved in 1977. Last previous edition approved in 2007 as D360607. DOI:10.1520/D3606-10E01.2For referenced ASTM standards, visit the ASTM website, www.a
14、stm.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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO B
15、ox C700, West Conshohocken, PA 19428-2959. United States15.2 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.5.2.2 Column BOne 4.6 m (15 ft) by 3.2 mm outs
16、idediameter stainless steel column packed with 20 mass % TCEPon Chromosorb P, 80 to 100 mesh.5.3 Recordera 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 mea
17、suring 0.1 volume % MEK withsatisfactory signal-to-noise. If a strip chart recorder is to beused, a 0 mV to 1 mV range recording potentiometer with aresponse time of 2 s or less and a maximum noise level of60.3 % of full scale is recommended. The detector strip chartrecorder combination must produce
18、a4mmdeflection for a2 L sample containing 0.1 volume % MEK when operated atmaximum sensitivity.5.4 Microsyringe 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 mL and 2 mL capacities calibratedin 0.01 mL; 5 mL
19、calibrated in 0.1 mL, for use in dispensingvolumes of benzene and toluene not covered by the volumetricpipets (see Specification E1044 and E1293) during preparationof standard samples (see 11.1).NOTE 1Other volume dispensing equipment capable of delivering thespecified volumes within the stated tole
20、rance limits may be used as analternative to the requirements stated in 5.5 and 5.6.5.7 Flasksvolumetric, 25 mL and 100 mL capacity.5.8 Vibratorelectric.5.9 Vacuum Source.5.10 Evaporatorvacuum, rotary.5.11 Flaskboiling, round-bottom, short-neck, with2440 standard taper joint, 500 mL capacity. Suitab
21、le for usewith evaporator (5.10).5.12 Lampinfrared.5.13 Buretsautomatic, with integral reservoir, 25 mL ca-pacity.6. Materials6.1 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 Phases
22、1, 2, 3-Tris(2-cyanoethoxy) propane(TCEP) and methyl silicone.36.4 Solvents:6.4.1 Methanolreagent grade. (WarningFlammable.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 Chlor
23、idefor cleaning columns.(WarningHarmful if inhaled. High concentrations can causeunconsciousness or death.)6.4.4 Acetonefor 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
24、can be harmful.)6.6 Calibration Standards6.6.1 Benzene99+mol %. (WarningPoison. Carcino-gen. Harmful or fatal if swallowed. Extremely flammable.Vapors can cause flash fires.)6.6.2 Isooctane (2,2,4trimethyl pentane)99+mol %.(Warning Extremely flammable. Harmful if inhaled.)6.6.3 Toluene(WarningFlamma
25、ble. Vapor harmful.)6.6.4 n-Nonane99+mol %. (WarningFlammable. Va-por harmful.)7. Sampling7.1 Gasoline(Warning Extremely 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
26、.1 Prepare two packing materials (one packing materialconsists of 10 mass % dimethylpolysiloxane on ChromosorbW; the other, 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 50
27、0 mL flask3Packed column liquid phases such as OV 101 are considered to be of thedimethylpolysiloxane type. Other equivalent phases can also be used. Consult withthe column manufacturer or phase supplier for information.TABLE 1 Instrument ParametersDetector thermal conductivityColumns: two, stainles
28、s 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) Chromosorb P, 80 to 100-meshReference column Any column or restriction may beused.Temperature:Sample inlet system, C 200Detector,
29、 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 0 to 1Chart speed, cm/min 1Sample size, L 2Total cycle time, min 8Backflush, min approximately 0.75AAThis back flush time mu
30、st be determined for each column system.D3606 1012(5.11). Dissolve5gofthedimethylpolysiloxane in approxi-mately 50 mL of chloroform. (WarningCan be fatal ifswallowed. Harmful if inhaled.) Pour the methyl silicone-chloroform solution into the flask containing the ChromosorbW. Attach the flask to the
31、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-cyanoethoxy) 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 inFIG. 1
32、 Pressure BackflushD3606 1013200 mL of methanol and pour into the flask containing theChromosorb P. Attach the flask to the evaporator (5.10),connect the vacuum, and start the motor. Turn on the infraredlamp and allow the packing to mix thoroughly until dry. (Donot heat the packing over 180 C.)9. Pr
33、eparation 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 stainless steel tubing in an upright positionand place a drain beaker under the outlet end of the tubing.Pour about 50 mLof methylene chloride ( Wa
34、rningHarmfulif inhaled. High concentrations can cause unconsciousness ordeath) into the funnel and allow it to drain through the steeltubing and into the drain beaker. Repeat the washing procedurewith 50 mL of acetone. (WarningHarmful if inhaled. Highconcentrations can cause unconsciousness or death
35、.) Removethe funnel and attach the steel tubing to an air line, using vinylFIG. 2 Valve BackflushD3606 1014tubing to make the connection. Remove all solvent 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
36、 the chromatograph. Pack the 0.8 m tubing (ColumnA) with the dimethylpolysiloxane packing (8.1.1) and the4.6 m tubing (Column B) with the TCEP packing (8.1.2) usingthe following procedure. Close one end of each tubing with asmall, glass wool plug, and connect this end to a vacuumsource by means of a
37、 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 appropriatepacking into the funnel until the column is full. While fillingeach column, vibrate the column with the electric vibrator tosettle the pack
38、ing. 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.10. Configuration of Apparatus and Establishment ofConditions10.1 Conditioning ColumnInstall Columns A and B asshown in Fig. 1 or Fig. 2 in accordance w
39、ith the systempreferred (5.1). Do not connect the exit end of Column B to thedetector until the columns have been conditioned. 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 Tempera
40、ture501210012150 1170 310.2 AssemblyConnect the outlet of Column B to thedetector port. Adjust the operating conditions to those 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.
41、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 column system (at an approximate gage pressure of205 kPa (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 an
42、d open B and C. The pressurereading on gage GAshould fall to zero immediately. If not,open the needle valve until the pressure falls to zero.10.3.1.3 Close Tap B. Adjust the secondary pressure regu-lator until the reading of gage GCis 3.5 kPa to 7 kPa (0.5 psito 1 psi) higher than observed in 10.3.1
43、.1.10.3.1.4 Open Tap B and adjust the backflush vent controlneedle valve until the pressure recorded on GAapproximates agage pressure of 14 kPa 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 ba
44、seline shift on switching from forward flow tobackflush. If there is a baseline shift increase the secondarypressure slightly.) (Fig. 1)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
45、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),measure 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/mi
46、n).10.3.2.3 Change the valve from forward flow to the back-flush position several times and observe the baseline. Thereshould be no baseline 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 b
47、alance thebaseline. (A persistent drift could indicate leaks somewhere inthe system.)10.4 Determine Time to BackflushThe time to backflushwill vary for each column system and must be determinedexperimentally as follows. Prepare a mixture of 5 volume %isooctane in n-nonane. Using the injection techni
48、que describedin 11.4 and with the preferred system (10.3)intheforward flowmode, inject 1 L of the isooctane n-nonane mixture. Allowthe chromatogram 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
49、signal returns tobaseline between the isooctane and n-nonane peaks. At thispoint all of the isooctane, but essentially none of the n-nonane,should have eluted. One half of the time determined shouldapproximate the “time to backflush” and should be from 30 sto 60 s. Repeat the run, including the injection, but switchingthe system 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 additionalrun
