1、Designation: D 3525 04An American National StandardStandard Test Method forGasoline Diluent in Used Gasoline Engine Oils by GasChromatography1This standard is issued under the fixed designation D 3525; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the use of gas chromatographyto determine the amount of gasol
3、ine in used lubricating oilsarising from their use in gasoline engines.1.2 There is no limitation for the determination of thedilution range, provided that the amount of sample plusinternal standard is within the linear range of the gas chro-matograph detector.1.3 This test method is limited to gas
4、chromatographsequipped with flame ionization detectors and programmableovens.NOTE 1The use of other detectors and instrumentation has beenreported. However, the precision statement applies only when the instru-mentation specified is employed.1.4 The applicability of this method to gelled used engine
5、oils has not been adequately investigated in order to ensurecompliance with the indicated repeatability and reproducibility.Gelled oils are defined as oils that develop structure onstanding, but that return to their original fluidity with lightagitation.1.5 The values stated in SI units are to be re
6、garded as thestandard.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 of regulatory requirements prior
7、 to use.2. Referenced Documents2.1 ASTM Standards:2E 260 Practice for Packed Column Gas ChromatographyE 355 Practice for Gas Chromatography Terms and Rela-tionshipsE 594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid ChromatographyE 1510 Practice for Installing Fus
8、ed Silica Open TubularCapillary Columns in Gas Chromatography3. Terminology3.1 Definitions:3.1.1 For definition of gas chromatography terms, refer toPractice E 355.3.2 Definitions of Terms Specific to This Standard:3.2.1 fuel dilution, nthe amount, expressed as a percent-age, of gasoline found in en
9、gine lubricating oil.3.2.1.1 DiscussionFuel dilution may be the result ofengine wear or improper performance.3.2.2 fuel diluent, nin used oil analysis, unburned fuelcomponents that enter the engine crankcase cause dilution ofthe oil.3.2.2.1 DiscussionIn this method, the fuel diluent com-ponents bein
10、g determined originate from gasoline.3.3 Abbreviations:3.3.1 Acommon abbreviation of hydrocarbon compounds isto designate the number of carbon atoms in the compound. Aprefix is used to indicate the carbon chain form, while asubscripted suffix denotes the number of carbon atoms.Example:normal decane
11、n-C10iso-tetradecane i-C144. Summary of Test Method4.1 A gas chromatographic technique is used for analyzingthe samples, by adding a known percentage of n-tetradecane asan internal standard, in order to determine the weight percentof gasoline fuel in the lubricating oil. A calibration curve isprevio
12、usly constructed which plots the gasoline fuel ton-tetradecane response ratio versus the weight percent ofgasoline fuel in lubricating oil mixtures containing a constantamount of internal standard. Mass percent of gasoline fuel inthe samples is determined by interpolation from the calibrationcurve.1
13、This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04 on Hydrocarbon Analysis.Current edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1976. Last previous edition approv
14、ed in 2002 as D 352593(2002)e1.2For 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 section
15、 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. Significance and Use5.1 Some fuel dilution of the engine oil may take placeduring normal operation. However, excessive fuel dilution is ofconcern
16、in terms of possible performance problems. Thismethod provides a means to determine the magnitude of thefuel dilution, providing the user with the ability to predictperformance problems and to take appropriate action.6. Apparatus6.1 Gas ChromatographAny gas chromatograph may beused that has the foll
17、owing performance characteristics:6.1.1 DetectorOnly a flame ionization detector can beused in this method. The detector must have sufficient sensi-tivity to detect 1.0 % n-tetradecane with a peak height of atleast 40 % of full scale on the data acquisition devise under theconditions prescribed in t
18、his method. For further guidance ontesting flame ionization detectors, refer to Practice E 594.When operating at this sensitivity level, detector stability mustbe such that a baseline drift of not more than 1 % full scale perhour is obtained. The detector must be capable of operatingcontinuously at
19、a temperature equivalent to the maximumcolumn temperature employed. Connection of the column tothe detector must be such that no temperature zones existbelow the column temperature (cold spots).6.1.2 Column Temperature ProgrammerThe chromato-graph must be capable of temperature program operation of
20、theoven over a range sufficient to establish a retention time of 0.25min (15 s) for the initial peak and to elute the internal standardtotally. A retention time repeatability of 0.3 min (18 s) must beachieved.6.1.3 Sample Inlet SystemThe sample inlet system mustbe capable of operating continuously a
21、t a temperature equiva-lent to the maximum column temperature employed. Anon-column inlet with some means of programming the inlettemperature, including the point of sample introduction, up tothe maximum temperature required can also be used. Connec-tion of the column to the sample inlet system must
22、 be such thatno temperature zones exist below the column temperature (coldspots).6.2 Data Acquisition SystemMeans must be provided formeasuring the accumulated area under the chromatogram. Thiscan be done by means of an electronic integrator or computerbased chromatography data system.6.2.1 Integrat
23、or/Computer SystemThe integrator/computer system must have chromatographic software capableof measuring the retention times and areas of eluting peaks(peak detection mode). The electronic range of the integrator/computer (for example, 1 V, 10 V) must be within the linearrange of the detector/electro
24、meter system used. It is desirablethat the system be capable of subtracting each area slice of ablank run from the corresponding area slice of a sample run.NOTE 2Best precision and automatic operation can be achieved withelectronic integration.NOTE 3Some gas chromatographs have an algorithm built in
25、to theiroperating software that allows a mathematical model of the baselineprofile to be stored in memory. This profile is automatically subtractedfrom the detector signal on subsequent sample analyses to compensate forany baseline offset. Some integration systems also store and automaticallysubtrac
26、t a blank analysis from subsequent analytical determinations.6.3 ColumnAny column and conditions may be used,provided that, under the conditions of the test, the separationsoccur in order of increasing boiling points and the columnperformance requirements described in 8.2.1 are met. Thecolumn resolu
27、tion, R, shall be at least 3 and not more than 8(see 8.2.1.1). Since a stable baseline is an essential requirementof this method, electronic single column compensation isrequired to compensate for column bleed, septum bleed,detector temperature control, constancy of carrier gas flow andinstrument dr
28、ift.6.4 Flow ControllersThe gas chromatograph must beequipped with mass flow controllers capable of maintainingcarrier gas flow constant to 61 % over the full operatingtemperature range of the column. The inlet pressure of thecarrier gas supplied to the gas chromatograph must be suffi-ciently high t
29、o compensate for the increase in column back-pressure as the column temperature is raised. An inlet pressureof 550 kPa (80 psig) has been found to be satisfactory with thecolumns described in Table 1.6.5 Sample Introduction Devices:6.5.1 Micro SyringeA micro syringe, usually 10 L, isused for sample
30、introduction.TABLE 1 Typical Operating ConditionsPacked Columns Open Tubular ColumnsColumn length, m (ft) 0.610 (2) 5 10Column outside diameter, mm (in.) 3.2 (1/8) Column inner diameter, mm (in.) 2.36 ( 0.093) 0.53Liquid phase methylsilicone gum or liquids cross-linked, bonded polydimethylsiloxanePe
31、rcent liquid phase 10 Support material crushed fire brick or diatomaceous earth Treatment acid wash Support mesh size 80/100 Stationary phase thickness, microns 0.88 2.65Column temperature, initial C 30 30Column temperature, final C 255 255Programming rate, C/min 6 6Carrier gas helium or nitrogen he
32、lium or nitrogenCarrier gas flow rate, mL/min 30 30Detector flame ionization detector flame ionization detectorDetector temperature, C 300 300Injection port temperature, C 255 255Sample size, L 0.7 0.1 0.2 (from 1/10 dilution in CS2)D35250426.5.2 Automatic sampling devices that reproducibly injectth
33、e same volume are highly recommended. The sample intro-duction devices should operate in a synchronous manner withthe gas chromatograph.6.6 Vials, 1-dram (3.7-mL), septum-capped, or those recom-mended by the manufacturer of the automatic sampling device.7. Reagents and Materials37.1 Purity of Reagen
34、tsReagent grade chemicals shall 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. Other grades may be used,provided it is first
35、 ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Liquid Phase for ColumnsAny nonpolar liquid phasesuitable for column operation above 300C may be used.Methylsilicone gums and liquids have been found to providethe pro
36、per chromatographic hydrocarbon elution characteris-tics for this test method.7.3 Solid SupportUsually crushed fire brick or diatoma-ceous earth is used in the case of packed columns. Where solidsupport is used, sieve size and support loading should be suchas will give optimum resolution and analysi
37、s time. In general,particle sizes ranging from 60 to 100 sieve mesh, and supportloadings of 3 to 10 %, have been found most satisfactory.7.4 Carrier GasHelium or nitrogen (WarningHeliumand nitrogen are compressed gases under high pressure), 99.99mole% or greater, shall be used with the flame ionizat
38、iondetector. Additional purification is recommended by the use ofmolecular sieves or other suitable agents to remove water,oxygen, and hydrocarbons. Available pressure must be suffi-cient to ensure a constant carrier gas flow rate (see 6.4).7.5 HydrogenHydrogen (WarningHydrogen is an ex-tremely flam
39、mable gas under high pressure), 99.99 mole%purity or greater, is used as fuel for the flame ionizationdetector (FID).7.6 AirCompressed air (WarningCompressed air is agas under high pressure and supports combustion), 99.99mole% purity or greater, is used as the oxidant for the flameionization detecto
40、r (FID).7.7 n-Tetradecane(WarningCombustible liquid; vaporharmful), 95 % minimum purity.7.8 n-Hexadecane(WarningCombustible liquid; vaporharmful), 95 % minimum purity.7.9 n-Octane(WarningFlammable liquid; harmful ifinhaled), 95 % minimum purity.7.10 Carbon Disulfide (CS2)(WarningCarbon disul-fide is
41、 extremely volatile, flammable, and toxic.)8. Preparation of Apparatus8.1 Column Preparation:8.1.1 Packed ColumnsAny satisfactory method used inthe practice of gas chromatography (see Practice E 260) thatwill produce a column meeting the requirements of 6.3 may beused. The column must be conditioned
42、 at the maximumoperating temperature until baseline drift due to columnbleeding has been reduced to less than 1 % per hour.8.1.1.1 The packed column can be conditioned very rapidlyand effectively using the following procedure: Connect thecolumn to the inlet but leave the detector end free. Purge the
43、column thoroughly at ambient temperature with carrier gas.Turn off the carrier gas and allow the column to depressurizecompletely. Seal off the open end (detector end) of the columnwith an appropriate fitting. Raise the column temperature to themaximum operating temperature and hold at this temperat
44、urefor at least 1 h with no flow through the column. Cool thecolumn to ambient temperature. Then remove the cap from thedetector end of the column and turn the carrier gas back on.Program the column temperature up to the maximum severaltimes with normal carrier gas flow. Connect the free end of thec
45、olumn to the detector.NOTE 4Difficulty in achieving the baseline drift requirement mayindicate column bleed due to insufficient conditioning.NOTE 5An alternative method of column conditioning, which hasbeen found effective for packed columns with an initial loading of 10 %liquid phase, consists of p
46、urging the column with carrier gas at the normalflow rate while holding the column at maximum operating temperature for12 to 16 h, while detached from the detector.8.1.2 Open Tubular ColumnsOpen tubular columns withcross-linked and bonded non-polar stationary phases are avail-able from many manufact
47、urers and are usually pre-conditioned. These columns have much lower column bleedthan packed columns. Column conditioning is still necessary(see Practice E 1510). The column can be conditioned veryrapidly and effectively using the following procedure.8.1.2.1 Once the open tubular column has been pro
48、perlyinstalled into the gas chromatograph inlet and tested to be leakfree, set the column and detector gas flows. Before heating thecolumn, allow the system to purge with carrier gas at ambienttemperature for at least 30 min.8.1.2.2 Increase the oven temperature about 5 to 10C perminute to the final
49、 operating temperature and hold for about 30min or until a stable baseline is observed.8.1.2.3 Cycle the gas chromatograph several times throughits temperature program until a stable baseline is obtained.8.2 System Performance Specifications:8.2.1 Column ResolutionResolution is specified to main-tain equivalence between different systems or laboratoriesemploying this test method. Resolution is determined using Eq1 following the analysis of a column resolution test mixtureprepared as follows.8.2.1.1 To test column resolution, p
