1、Designation: D7753 12 (Reapproved 2016)Standard Test Method forHydrocarbon Types and Benzene in Light PetroleumDistillates by Gas Chromatography1This standard is issued under the fixed designation D7753; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he 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. Scope1.1 This test method covers and provides for the quantita-tive determination of total sat
3、urates, total olefins, total aromat-ics and benzene in light petroleum distillates having a finalboiling point below 215 C by multidimensional gas chroma-tography. Each hydrocarbon grouping as well as benzene canbe reported in both volume and mass percent.1.2 This test method is applicable to light
4、petroleum distil-lates such as oxygenate-free motor gasoline or spark ignitionfuels, naphthas and hydrocarbon solvents over the contentranges from 1 % (V/V) to 70 % (V/V) total olefins, 1 % (V V)to 80 % (V/V) total aromatics and 0.2 % to 10 % (V V)benzene. This test method may apply to concentration
5、s outsidethese ranges, but the precision has not been determined.Interlaboratory testing for precision used full range blendingstreams, such as FCC, reformates and spark ignition fuel orblended motor gasolines.1.3 This test method is not intended to determine oxygen-ated components. Light petroleum
6、distillate products such asmotor gasoline may contain oxygenates. Oxygenates such asmethyl tert-butyl ether (MTBE), tert-amyl methyl ether(TAME), ethyl tert-butyl ether (ETBE), ethanol and methanoletc. will coelute with specific hydrocarbon groups. If there isany suspicion the sample contains oxygen
7、ates, the absence ofoxygenates should be confirmed by other standard test methodssuch as Test Methods D4815, D5599,orD6839 before usingthis test method.1.4 This test method is not applicable for the determinationof individual hydrocarbon components with the exception ofbenzene. Test Method D6733 may
8、 be used to determine a largenumber of individual hydrocarbons to complement this testmethod.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, as
9、sociated 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.2. Referenced Documents2.1 ASTM Standards:2D4815 Test Method for Determination of MTBE, ETBE,TAME,
10、 DIPE, tertiary-Amyl Alcohol and C1to C4Alco-hols in Gasoline by Gas ChromatographyD5599 Test Method for Determination of Oxygenates inGasoline by Gas Chromatography and Oxygen SelectiveFlame Ionization DetectionD6733 Test Method for Determination of Individual Com-ponents in Spark Ignition Engine F
11、uels by 50-MetreCapillary High Resolution Gas ChromatographyD6839 Test Method for Hydrocarbon Types, OxygenatedCompounds, and Benzene in Spark Ignition Engine Fuelsby Gas Chromatography3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 aromatics, nmass or volume % of monocyclicar
12、omatics and polycyclic aromatics (for example,naphthalenes), aromatic olefins and C8+cyclodienes com-pounds.3.1.2 C7+aromatics, nmass or volume % of all otheraromatics compounds (see 3.1.1) in sample not includingbenzene.3.1.3 olefins, nmass or volume % of alkenes, plus cy-cloalkenes and some di-ole
13、fins.3.1.4 olefins trap, nspecific column utilized to selectivelyretain olefins from mixture of olefins and saturates. The trapmust have good reversibility to capture and release olefins bychanging the temperature.3.2 Acronyms:1This test method is under the jurisdiction of ASTM Committee D02 onPetro
14、leum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved Oct. 1, 2016. Published November 2016. Originallyapproved in 2012. Last previous edition approved in 2012 as D7753 12.DOI:10.1520/D7753-12R16.2
15、For 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C7
16、00, West Conshohocken, PA 19428-2959. United States13.2.1 BCEF- N,N-bis(-cyanoethyl) formamidegas chro-matography stationary phase.4. Summary of Test Method4.1 Fig. 1 shows a separation scheme of the various hydro-carbon types and benzene analysis. The instrumental configu-ration is shown in Fig. 2.
17、 The valves are actuated at predeter-mined times to direct different components to differentcolumns.As the analysis proceeds, different hydrocarbon typesand benzene elute and are detected by a flame ionizationdetector (FID).4.2 The mass concentration of different hydrocarbon typesand benzene are det
18、ermined by the application of averagerelative response factors to the areas of the detected peaksfollowed by normalization to 100 %.4.3 The volume percent concentration of different hydrocar-bon types and benzene can be determined by the application ofaverage density factors to the calculated mass c
19、oncentration ofthe detected peaks followed by normalization to 100 %.4.4 This test method is not intended to determine com-pounds that contain oxygenates, such as ethanol, etc. Suchoxygenates interfere with the analysis of the hydrocarbons.4.5 Analysis time of a sample is approximately 15 min.5. Sig
20、nificance and Use5.1 Knowledge of the olefinic, aromatic, and benzene con-tent is very important in quality specifications of petroleumproducts, such as spark ignition fuels (gasoline) and hydrocar-bon solvents. Fast and accurate determination of hydrocarbontypes and benzene of petroleum distillates
21、 and products is alsoimportant in optimization of process units.5.2 This test method provides a fast standard procedure fordetermination of hydrocarbon types and benzene in lightoxygenate-free petroleum distillates and products.6. Interferences6.1 C12+aliphatic hydrocarbon compounds (not includingC1
22、2) may not be fully separated from benzene in the polarcolumn, thus the determination of aromatics and benzene maybe affected.6.2 Different types of oxygenated compounds in somepetroleum products will elute with specific hydrocarbon groupsand interfere with the analysis of the hydrocarbons.6.3 Comme
23、rcial detergent, antioxidant, antiknock additivesand dyes utilized in some petroleum products have been foundnot to interfere with this test method.6.4 Dissolved water in samples has been found not tointerfere with this test method.7. Apparatus7.1 The analysis system is comprised of a gas chromato-g
24、raph with manual or automated sample injection, and specifichardware modifications. These modifications include columns,olefins trap, valves, and temperature controllers.7.2 Gas Chromatographcapable of temperature pro-grammed operation at specified temperature, equipped with avaporization inlet that
25、 can be a packed column inlet, a flameionization detector (FID), and necessary flow controllers.7.3 Sample Introduction Systemmanual or automaticinjector, capable of injecting a 0.1 L volume of sample.Automated injector is recommended.7.4 Gas Flow or Pressure Controllerswith adequate pre-cision to p
26、rovide reproducible flow rate of carrier gas to thechromatographic system, hydrogen and air for the flameionization detector. Control of air pressure for automatedvalves operation is required.7.5 Data Acquisition Systemchromatographic workstationshall meet the following specifications:7.5.1 Sampling
27、 rate of at least 10 points per second.7.5.2 Capacity for 100 peaks for each analysis.7.5.3 Normalized areas percent calculation with responsefactors.7.5.4 Area summation of peaks that are split or of groups ofcomponents that elute at specific retention times.7.5.5 Noise and spike rejection capabili
28、ty.7.5.6 Manual baseline adjusting function, as required.7.6 Valvescolumn and trap switching, automated rotaryvalves are recommended.FIG. 1 Separation Scheme of Hydrocarbon Types and Benzene AnalysisD7753 12 (2016)27.7 Gas Purifiersto remove moisture and oxygen fromcarrier gas.7.8 Temperature Contro
29、llersthe independent temperaturecontrol of the polar column, olefins trap, switching valves andsample connecting lines is required. All of the system compo-nents that contact the sample should be heated to a temperaturethat will prevent condensation of any sample component. Table1 lists the system c
30、omponents and approximate operatingtemperatures. Some of the components operate isothermally,while others require temperature programming. Temperaturecontrol may be by any means that will meet the requirementslisted in Table 1.8. Reagents and Materials8.1 Gases:8.1.1 Carrier GasNitrogen or Helium. I
31、LS precision ofthis test method was obtained using nitrogen as the carrier gas.NOTE 1Legend:1injector2vaporization room3, 3Bvalve 14polar column5olefins trap6balance column7polar column oven 18olefins trap oven9valves oven10FID11data processing unitFIG. 2 Configuration of Analytical SystemTABLE 1 Te
32、mperature Control Ranges of System ComponentsComponent Typical OperatingTemperature, CHeatingModePolar Column 100120 isothermalOlefin Trap 125210 temperature programmed40C/minSwitching Valves 100140 isothermalSample Lines 100140 isothermalD7753 12 (2016)3Better than 99.999 % pure. (WarningCompressed
33、 gasesunder high pressure.) Gas purifiers may be used to attain therequired purity or to ensure a stable signal baseline.8.1.2 HydrogenBetter than 99.999 % pure. (WarningExtremely flammable gas under high pressure.) Gas purifiersmay be used to attain the required purity or to ensure a stablesignal b
34、aseline.8.1.3 Air, Compressed2.0. Theretention time ratio of benzene and toluene (ttoluene/tbenzene)shall be larger than 1.25, the resolution shall be 1.1 (see Note1). A BCEF column which is 25 % BCEF coated on acidwashing diatomite supporter is recommended as the polarcolumn. The length of the pola
35、r column is approximately 5 mand the inside diameter is approximately 2 mm. Other columnswhich meet the separation requirements can be used. Fig. 3 isa polar column separation performance check chromatogramwith system validation test sample.tbenzene/tundecene5 1.59Rbenzene/tundecene5 2.4ttoluene/tbe
36、nzene5 1.31Rtoluene/tbenzene5 1.25NOTE 1RS52tR22 tR1!Wb21Wb15tR22 tR1!Wb1where: tR2tR18.2.2 Olefin TrapThe olefin trap shall have excellentreversibility performance.At a lower temperature, for example,130 C, the trap shall retain the olefins in the sample and passall saturates before benzene elutes
37、from the polar column. At ahigher temperature, for example, 210 C, the trap shall quan-titatively release the retained olefins. The adsorbent of olefinsusually is a silver ion based material. Any olefin trap whichsatisfies the performance requirements can be used. Theperformance of the trap can be v
38、erified first with the systemvalidation test sample (10.2) and, once established, can bemonitored either with the validation test sample or actualproduction or consensus reference quality sample.8.3 System Gravimetric Validation Test SampleQuantitative mixtures of pure hydrocarbons are used to verif
39、ythe operating temperature, valve switching times and valida-tion of the system analysis accuracy. The validation samplecomposition and approximate component concentrations areshown in Table 2.8.4 Quality Control SamplesProduction or consensussamples, or both, used to routinely monitor validation of
40、analysis system. Any production or interlaboratory or certifiedreference sample which approximates similar compositions tothe samples to be analyzed may be designated as the qualitycontrol sample. Quality control samples shall be selected suchthat they fall within the range and composition of sample
41、s to beanalyzed. The quality control samples shall be stable for aspecified period of use and storage conditions. It is preferredthat the quality control samples be ampoulized to safeguardtheir composition integrity.9. Preparation of Apparatus9.1 The configuration of the analyzer system is shown inF
42、ig. 1. Some system modules may have independent tempera-ture controlled components. If using a commercial analyzer,FIG. 3 Polar Column Separation Performance Check ChromatogramD7753 12 (2016)4consult the manufacturers instructions or guidelines for prepa-ration of the instrument.9.2 All supply gas p
43、ressure shall be adequate to ensureproper mass flow control and air or nitrogen actuated valveoperation. The approximate supplying gas pressure values arelisted in Table 3.9.3 Impurities in the carrier gas will have a detrimentaleffect on the performance of column and olefin trap. Therefore,appropri
44、ate gas purifiers shall be installed to ensure goodquality gases.9.4 The system validation test sample or quality controlsample can be used to determine the valve switching times. Theolefins trap temperature is determined in order to meet theretention requirement for olefins. The approximate instrum
45、entoperating conditions are listed in Table 4.10. System Checks and Standardization10.1 Instrument System Reliability CheckingThe checkingof the analytical system is very important to ensure test resultsreliability. The following gives a guideline:10.1.1 Use the system gravimetric validation test sa
46、mple in8.3 to establish the quantitative performance of the system. Thestandard is used during setting up the instrument and periodi-cally afterwards to verify its performance. The required abso-lute deviation between obtained results and blending concen-tration values as specified in Table 2 is 1.6
47、 % for total saturates,1.2 % for total olefins, 1.4 % for total aromatics, and 0.05 %for benzene.10.1.2 Quality Control (QC) SamplePreferably from simi-lar production, or from an interlaboratory study or equivalent,or a combination thereof. Such quality control samples is usedto routinely monitor th
48、e operation of the chromatographicsystem and verify that reported concentrations are within theprecision of the test method. The quality sample shall beanalyzed for each batch of samples. Depending on the rangeand composition of the samples to be analyzed, more than onequality control sample may be
49、necessary. The QC sample shallbe of sufficient volume to provide an ample supply for theintended period of use and it shall be homogeneous and stableunder the anticipated storage conditions. The quality controlsample should have similar composition and hydrocarbondistribution as the sample with highest olefin concentrationroutinely analyzed to safeguard against potential olefin break-through from the olefin trap. The sample is analyzed usingprocedure described in 11.3 and monitored by SQC.10.2 Olefin Trap Performance Checking
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