1、Designation: D7845 13Standard Test Method forDetermination of Chemical Species in Marine Fuel Oil byMultidimensional Gas Chromatography MassSpectrometry1This standard is issued under the fixed designation D7845; 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. Scope1.1 This test method covers the quantitative determinationof a variety of chemica
3、l species in marine fuel oil (bunker fueloil) by gas chromatography mass spectrometry. By using thesame conditions and by selecting required mass spectralselected ions, the test method may be used for the determina-tion of other species than those for which precision statementsand limits of detectio
4、n have been established.1.2 An example list of chemical species for which a limit ofquantification has been determined by means of this testmethod is given in Table 1.1.3 Other refinery hydrocarbon fractions and their mixturesmay be tested using the same test method conditions. However,the precision
5、 of this test method reflects the compounds inTable 1.1.4 Results are reported to the nearest 1.0 mg/kg.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,
6、 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 of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4307 Practice for Preparation of Liquid Ble
7、nds for Use asAnalytical StandardsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3. Terminology3.1 Definitions:3.1.1 direct or open split interface, nany GC/MS interfaceused to maintain atmospheric pressure
8、 at capillary columnoutlet.3.1.2 reconstructed ion chromatogram (RIC), na limitedmass chromatogram representing the intensities of ion massspectrometric currents for only those ions having particularmass to charge ratios used in this test method to selectivelyextract and identify components in the p
9、resence of a complexhydrocarbon matrix.3.1.3 total ion chromatogram (TIC), nmass spectrometercomputer output representing either the summed intensities ofall scanned ion currents or a sample of the current in the ionbeam for each spectrum scan plotted against the correspondingspectrum number.3.1.4 w
10、all coated open tubular (WCOT), na type ofcapillary column prepared by coating or bonding the insidewall of the capillary with a thin film of stationary phase.4. Summary of Test Method4.1 A suitable internal standard, ethylbenzene d-10 is addedto the sample, which is then introduced into a gas chrom
11、ato-graph equipped with two columns configured with a Deansswitching system between the two columns. The sample firstpasses through the polydimethylsiloxane (WCOT) pre-columnwhich then performs a separation of the light hydrocarbonfraction and eliminates the high boiling hydrocarbon fraction tovent.
12、 The compounds of interest and internal standard aretransferred to the high resolution polydimethylsiloxane(WCOT) analytical column for chromatographic separation.An auxiliary carrier gas is used to elute higher boilinghydrocarbons from the pre-column in back flush mode in orderto prepare for the ne
13、xt analysis cycle. The resulting chromato-gram is then processed by mass spectral analysis based onselected or extracted ion monitoring.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0M on M
14、ass Spectroscopy.Current edition approved April 1, 2013. Published May 2013. DOI: 10.1520/D7845-13.2For 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 Doc
15、ument Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 The test method allows the quantitation of chemicalspecies at low levels in marine fuel oils and cutter stocks. Agreat ma
16、ny types and concentrations of chemical species arefound in marine fuel oils.Aroot cause relationship between thepresence of such species or their concentration in fuels and anyfailure modes allegedly induced by the use of these fuels hasnot been established. This method is necessary to establish te
17、stconditions required for future ISO 8217:2010 Petroleumproducts- Fuels (class F)-Specifications of marine fuel oils asdefined in section 5.5 and Annex B item (d). Additionalcompounds may be determined by using the same conditionsand by selecting required mass spectral selected ions, accord-ingly.6.
18、 Apparatus6.1 Gas Chromatography:6.1.1 Gas ChromatographAny gas chromatographequipped with a flame ionization detector (FID) and havingsensitivity of 0.01 mg/kg. The gas chromatograph must becapable of linear temperature control from 50 to 320C for thecapillary column oven. The gas chromatograph mus
19、t be ca-pable of controlling multiple valve events. Carrier gas flowcontrollers and or electronic pressure control modules shall becapable of precise control where the required flow rates arelow. Pressure control devices and gauges shall be capable ofprecise control for the typical pressures require
20、d. The tempera-ture program rate must repeat to within 0.1C and provideretention time repeatability of 0.05 min throughout the tem-perature program.6.1.2 Pre-Column ColumnWCOT Column, 25 m long by0.53-mm inside diameter fused silica WCOT column with a1.0-micron film thickness of polydimethyl siloxan
21、e or anycolumn with suitable chromatographic resolution.6.1.3 Analytical ColumnWCOT Column, 100 m by0.25-mm inside diameter fused silica WCOT column with a0.5-micron film thickness of polydimethyl siloxane or anycolumn with suitable chromatographic resolution.6.1.4 Purged Packed InjectorAn injection
22、 port that allowscontrolled injection of the sample at a temperature sufficient topass the high boiling point fraction to the pre-column or anygas chromatographic injector system to perform the samefunction.6.1.4.1 The injection port liner shall be replaced to removenon-volatile materials.6.1.5 Elec
23、tronic Pressure ControlElectronic pneumaticcontrol of carrier gas flows. It can be flow or pressureprogrammed to speed up elution of components.6.1.6 Low-Volume Connector and TeesA special union ortee for connecting two lengths of tubing 1.6-mm insidediameter and smaller; sometimes referred to as a
24、zero dead-volume union, tee, or an active splitting device.6.1.7 Pre-ColumnApolydimethylsiloxane WCOT columnused to isolate the light hydrocarbons to include methane ton-hexadecane from the higher boiling portion of the sample fortransfer to the analytical column for further separation andquantifica
25、tion.6.1.8 Deans Switching Backflush Configuration3(Fig.1)A column backflush configuration utilizing dynamic pres-sure differential which provides suitable means to remove theheavier hydrocarbon fraction from the pre-column or anysimilar configuration that allows for controlled chromato-graphic sepa
26、ration of components of interest and heavierhydrocarbon fraction. An alternative Deans switching back-flush configuration is shown on Fig. 2.6.2 Mass Spectrometry:6.2.1 Mass Spectrometer, capable of producing electronionization spectra at 70 electron volts or higher, and capable ofscanning the range
27、 of the specified quantitation masses or(m/e). The mass scan range shall cover the masses of interestfor quantitation and should yield at least 5 scans across thepeak width at half peak width fora1to3mg/kg ethylbenzened10 peak and cover the masses of interest for quantitation. Ascan range set for sp
28、ecific ions is defined in Table 2.6.2.1.1 The mass spectrometer shall be capable of beinginterfaced to a gas chromatograph and WCOT columns. Theinterface shall be at a high enough temperature to preventcondensation of components boiling up to 350C. Usually,20C above the final column temperature is a
29、dequate. Directcolumn interface to the mass spectrometer may be used. Anopen split interface with computer controlled programmableflow controller(s) may also be used, to maintain all componentswithin the linearity of the mass spectrometer and at the sametime maintain detectability of lower concentra
30、tion chemicalcomponents.3Deans, David R., Chromatographia, Vol 1, 18-22, 1968.TABLE 1 Component TableLimit of Quantitationmg/kgn-butyl alcohol 10Cyclohexanol 10n-butyl ether 10n-butyl acylate 10Styrene 10alpha-pinene 10Phenol 20alpha-methyl styrene 10beta-pinene 104-methyl styrene 10trans-B-methyl s
31、tyrene 103-methyl styrene 102-methyl styrene 10Dicyclopentadiene 10Limonene 10Indene 201-phenyl ethanol 20para, alpha-Dimethyl styrene 202,5 dimethyl styrene 202,4 dimethyl styrene 202-phenyl ethanol (phenylethanol) 202-Ethyl Phenol 502,4 Dimethyl Phenol 204-Ethyl Phenol (co elutes with 3-ethylpheno
32、l) 202-Phenoxy-1-propanol 502-Phenoxy ethanol 504-isopropylphenol 501-Phenoxy-2-Propanol 20Styrene Glycol 50D7845 1326.2.1.2 Acquistion mode selected ion monitoring (SIM)extracted ion mode or full scan mode using the quantitative andqualitative ions referenced in Table 2. Additional compoundsmay be
33、added by selecting and collecting data in full scanmode.6.2.1.3 Tuning shall be performed for low mass resolutionusing perfluorotributylamine mass fragment ions at m/z 69,131 and 219 amu. The mass spectrometer is tuned eitherautomatically or manually for optimum performance.7. Reagents and Materials
34、7.1 Purity of ReagentsReagent grade chemicals should beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used
35、,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Carrier GasHelium and hydrogen have been usedsuccessfully. The recommended minimum purity of the carriergas used is 99.999 mol %. Additional purif
36、ication usingcommercially available scrubbing reagents may be necessaryto remove trace oxygen, which may deteriorate the perfor-mance of the GC WCOT.7.3 Calibration StandardThis standard shall be preparedby adding the chemicals to include those in Table 1 preparedfrom high (99+ %) purity reagent gra
37、de materials.7.4 Standards for Calibration and IdentificationChemicalcompounds used to prepare standards should be 99 % orgreater purity (see Table 1). If reagents of high purity are notavailable, an accurate assay of the reagent shall be performedusing a properly calibrated GC or other techniques.
38、Theconcentration of the impurities that overlap the other calibra-tion components shall be known and used to correct theconcentration of the calibration components. The use of onlyhigh purity reagents is strongly recommended because of the4Reagent Chemicals, American Chemical Society Specifications,
39、 AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc.
40、 (USPC), Rockville,MD.FIG. 1 Deans Switching Backflush, Configuration AFIG. 2 Deans Switching Backflush, Configuration BD7845 133error that may be introduced from impurity corrections. Stan-dards are used for calibration as well as for establishing theidentification by retention time in conjunction
41、with massspectral match.7.5 n-hexadecane99+ % purity or better.7.6 Dilution SolventsReagent grade toluene, 99.9 % (orsuitable dilution solvent).7.7 Internal StandardsDeuterated analog of ethylbenzene,as specified, shall be used as internal standard because of thesimilar chromatographic characteristi
42、cs as the componentsanalyzed.8. Preparation of Apparatus8.1 AssemblyConfigure the GC system in a multidimen-sional configuration as described in Table 3 and Table 4.Connect the WCOT columns to the chromatographic system,including the multidimensional switching device, using lowvolume connectors and
43、inert narrow bore tubing. It is importantto minimize the volume of the chromatographic system thatcomes in contact with the sample; otherwise, peak broadeningwill occur.8.2 This section provides details to establish the configura-tions described in Fig. 1. For other column configurations,adjust back
44、flush and or cut times, accordingly.8.3 It is essential that the appropriate backflush time bedetermined to prevent heavy contaminants from reaching theanalytical column and potentially interfering with the determi-nation of compounds of interest.8.4 Setting the Backflush Time for Configuration AThe
45、pre-column connected to the analytical column and the massspectrometer as shown in Fig. 1 inject the calibration standardand record the chromatogram. Identify the peaks. The retentiontime data are used to set the valve on time to assure thecompound peaks are not backflushed. The retention timesshoul
46、d be incorporated into the software timed events beforecontinuing with sample analysis. Assure all of the compoundsof interest are present and high boiling hydrocarbons arebackflushed consistently. Assure the retention time data isrepeatable. If retention time shifts are encountered check forleaks t
47、o include replacing septum and that all column and valveconnections are leak free.8.4.1 The procedure used is as follows:8.4.1.1 Prepare a timing standard containing all of thecompounds of interest.8.4.1.2 Inject the timing standard into the GC in the fore-flush position with no backflush.8.4.1.3 An
48、alyze the resulting chromatogram and determinethe retention time of each of the compound peaks. See Figs.3-5.8.4.1.4 Starting at an arbitrary backflush time (4 min is agood starting point) reinject the sample and analyze thechromatogram for the presence of the compound peaks includ-ing C16.TABLE 2 M
49、ass Spectrometer Compound Quantitation Ions (Retention Time Data Based on Configuration A)RetentionTimeCompound CAS # Quantifying Qualifier 1 Qualifier 2 Qualifier 321.55 Ethylbenzene-d10 25837-05-2 116 11513.55 n-butyl alcohol 71-36-3 56 7422.58 Cyclohexanol 108-93-0 82 100 4422.61 n-butyl ether 142-96-1 87 101 13022.78 n-butyl acylate 141-32-2 55 128 7323.23 Styrene 100-42-5 10426.03 alpha-pinene 80-56-8 93 136 12126.66 Phenol 108-95-2 94 6627.79 alpha-methyl styrene 98-83-9 118 10328.21 beta-pinene 19902-08-0 93 136 12128.46 4-methyl styrene 622-97-9
