1、Designation: D7183 15Standard Test Method forDetermination of Total Sulfur in Aromatic Hydrocarbons andRelated Chemicals by Ultraviolet Fluorescence1This standard is issued under the fixed designation D7183; the number immediately following the designation indicates the year oforiginal adoption or,
2、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. Scope*1.1 This test method covers the determination of sulfur inaromatic hydrocarbons, the
3、ir derivatives, and related chemi-cals.1.2 This test method is applicable to samples with sulfurconcentrations from 0.5 to 100 mg/kg. With careful analyticaltechnique, this method can be used to successfully analyzeconcentrations below the current scope (see Appendix X1).1.3 The following applies fo
4、r the purposes of determiningthe conformance of the test results using this test method toapplicable specifications, results shall be rounded off in accor-dance with the rounding-off method of Practice E29.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement
5、 are included in thisstandard.1.5 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 limitation
6、s prior to use. For specific hazardstatements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D1555 Test Method for Calculation of Volume and Weightof Industrial Aromatic Hydrocarbons and CyclohexaneD3437 Practice for Sampling and Handling Liquid CyclicProductsD6809 Guide for Quality Contr
7、ol and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Other DocumentsOSHA
8、 Regulations, 29 CFR paragraphs 1910.1000 and1910.120033. Terminology3.1 oxidative pyrolysis, na process in which a sample iscombusted in an oxygen-rich atmosphere at high temperatureto break down the components of the sample into elementaloxides.3.2 ultraviolet fluorescence, nradiation in the regio
9、n of theelectromagnetic spectrum including wavelength from 100 to3900A that excites SO2to (SO2*).4. Summary of Test Method4.1 A specimen is either directly injected or placed in asample boat. The boat is then inserted into a high temperaturecombustion tube where the sulfur is oxidized to sulfur diox
10、ide(SO2) in an oxygen-rich atmosphere. Water produced duringthe sample combustion is removed and the sample combustiongases are next exposed to ultraviolet (UV) light. The SO2absorbs the energy from the UV light and is converted toexcited sulfur dioxide (SO2*). As it returns to a stable state,light
11、is emitted and detected by a photomultiplier tube and theresulting signal is a measure of the sulfur contained in thespecimen.5. Significance and Use5.1 Some process catalysts used in petroleum and chemicalrefining can be poisoned when trace amounts of sulfur-bearingmaterials are contained in the fe
12、edstocks. This test method canbe used to determine sulfur in process feeds, sulfur in finishedproducts, and can also be used for purposes of regulatorycontrol.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibil
13、ity ofSubcommittee D16.04 on Instrumental Analysis.Current edition approved June 1, 2015. Published June 2015. Originallyapproved in 2007. Last previous edition approved in 2012 as D7183 12. DOI:10.1520/D7183-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cus
14、tomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.a
15、ccess.gpo.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Interferences6.1 Halogens present in the specimen in concentrationsgreater than 10 % and nitrogen concen
16、trations of 1500 mg/kgor greater can interfere.6.2 Moisture produced during the combustion step caninterfere if not removed prior to the gas entering the detectorcell.7. Apparatus7.1 Pyrolysis FurnaceAn electric furnace capable ofmaintaining a temperature sufficient to volatilize and pyrolyzeall the
17、 sample and oxidize sulfur to SO2. The actual tempera-ture should be recommended by specific instrument manufac-turer.7.2 Quartz Pyrolysis TubeCapable of withstanding 900 to1200C. The tube should be recommended by the instrumentmanufacturer.7.3 Microlitre SyringeCapable of delivering from 5 to 250L
18、of sample. Check with the instrument manufacturer forrecommendations for specific sample requirements.7.4 Constant Rate Injector SystemIf the sample is to beintroduced into the pyrolysis furnace via syringe, use aconstant rate injector or a liquid introduction module.7.5 Liquid Auto-SamplerCapable o
19、f injecting 5 to 250 Lof sample.7.6 Automatic Boat Drive SystemIf the instrument isequipped with an inlet system, a device for driving the boatinto the furnace at a controlled and repeatable rate is required.7.7 Flow ControlThe instrument must be equipped withflow controllers capable of maintaining
20、a constant supply ofoxygen and carrier gas.7.8 Drier TubeThe instrument must be equipped with amechanism for removal of water vapor.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. It is intended that all reagents shall conform tothe specifications of the Committee
21、 on Analytical Reagents ofthe American Chemical Society,4where such specifications areavailable, unless otherwise indicated. Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8
22、.2 Inert GasEither argon (Ar) or helium (He) may beused. The purity should be no less than 99.99 mol %.8.3 Oxygen GasThe purity should be no less than 99.99mol %.8.4 SolventThe solvent chosen should be capable ofdissolving the sulfur compound. The solvent of choice shouldhave a boiling point similar
23、 to the sample being analyzed.Suggested possibilities include, but not limited to methanol,iso-octane, and p-xylene (see Note 1 and Note 2).NOTE 1A quick screening can be conducted by injecting the solventand sample once or twice and comparing relative area counts.NOTE 2All solvents should have know
24、n sulfur content or known to beless than what will interfere with results.8.5 DibenzothiopheneFW184.26, 17.399 % (m/m) Sulfur(see Note 3).NOTE 3A correction for chemical impurity is required. Normally98 %.8.6 Quartz WoolIf needed.8.7 Sulfur Stock Solution, approximately 870 to 1044 gS/mlThis standar
25、d may be purchased if desired. Prepare astock solution by accurately weighing approximately 0.5 to 0.6g of dibenzothiophene to the nearest 0.1 mg into a tared 100mL volumetric flask. Record the weight. Dilute to volume withthe selected solvent. Use Eq 1 to determine the concentrationof stock solutio
26、n. This stock solution can be further diluted todesired sulfur concentrations (see Note 4 and Note 5). Alter-nate volumes of solutions may be prepared so long as thepreparation meets the concentration specified.g S/ml solvent 5g of DBT! 3 .174! 3 Purity of DBT! 3 106!100 ml of Solvent(1)where:DBT =
27、dibenzothiopheneSinDBT = 17.3994 %NOTE 4Working standards should be remixed on a regular basisdepending upon frequency of use and age. Typically, stock solutions havea useful life of about 3 months.NOTE 5Check all new calibration standards against the previousstandard.9. Hazards9.1 Consult the curre
28、nt version OSHA regulations, suppli-ers Material Data Sheets, and local regulations for all mate-rials used in this test method.9.2 High temperature is employed in this test method. Extracare must be exercised when using flammable materials nearthe furnace.9.3 WarningExposure to excessive quantities
29、 of ultravio-let light is injurious to health. The operator must avoidexposing any part of their person, especially their eyes, notonly to direct UV light but also to secondary or scatteredradiation that is present.10. Sampling10.1 Consult guidelines for taking samples from bulk con-tainers in accor
30、dance with Practice D3437.11. Preparation of Apparatus11.1 Set-up the instrument in accordance with manufactur-ers instructions.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American
31、 Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D7183 15211.2 Adjust gas flows and pyrolysis temperature(s) to theoperating conditions re
32、commended by the manufacturer.11.3 The actual operation of injecting a sample will varydepending upon the instrument manufacturer and the type ofinlet system used.11.4 An autosampler or a constant rate injector must be usedwhen using an instrument equipped with a vertical furnace.11.5 Prebake the sa
33、mple boats to be used for the determi-nation.12. Calibration and Standardization12.1 Using the sulfur standard stock solution (see 8.7),make a series of calibrations standards covering the range ofexpected sulfur concentration. If the expected levels include 0to 1.0 mg/kg and 1 to 100 mg/kg, then tw
34、o curves should bemade to cover the entire range, one from 0 to 1.0 mg/kg (lowcurve) and one from 1.0 to 100 mg/kg (high curve).NOTE 6When looking for levels of sulfur below 1 mg/kg make acalibration curve using an autosampler or constant rate injector andstandards, made from the sulfur stock soluti
35、on, to cover the expectedrange of samples. Follow manufacturers recommendations for construct-ing the curve.NOTE 7When looking for concentrations from 1 mgS/kg to 100mgS/kg, follow manufacturers recommendations for constructing thecurve.12.2 The sample size can be determined eithervolumetrically, by
36、 syringe or by mass.12.3 Volumetric measurement can be utilized by filling thesyringe with standard, carefully eliminating all bubbles, andpushing the plunger to a calibrated mark on the syringe, andrecording the volume of liquid in the syringe. After injectingthe standard, read the volume remaining
37、 in the syringe. Thedifference between the two volume readings is the volume ofstandard injected. This test method requires the known ormeasured density, to the third decimal place.12.4 Alternatively, the syringe may be weighed before andafter the injection to determine the weight of the sampleinjec
38、ted. This technique provides greater precision than thevolume delivery method, provided a balance with a precisionof 60.0001 g is used.12.5 Follow the instrument manufacturers recommendationfor introducing samples into the instrument.12.6 If there are any problems with the calibration standardsfollo
39、w the instrument manufacturers recommendations tocorrect.12.7 Construct a linear regression curve (g S versus Area)using as many points as recommended by the instrumentmanufacturer.12.8 The linear regression curve should have a minimum of0.99 correlation coefficient. If it does not, examine each poi
40、nton the curve to determine which point or points are out. Correctthe problem and run new Standards.13. Procedure13.1 Obtain a test specimen using the procedure describedin Section 10. The sulfur concentration in the test specimenmust be less than the concentration of the highest standard andgreater
41、 than the concentration of the lowest standard used inthe calibration.13.2 Follow the instrument manufacturers recommenda-tions for sample size.13.3 Follow the instrument manufacturers recommenda-tions for introducing samples into the instrument.13.4 Determine the sulfur concentration, by the averag
42、e ofthree determinations, calculated by the instrument software.Make sure replicates are repeatable.14. Calculation14.1 All calculations are performed by the software, andresults are displayed and printed out in ppm (mg/kg) asappropriate. The density is input during sample data entry andis used by t
43、he instrument to convert from wt./vol. to wt./wt.14.2 Use Test Method D1555 for measurements utilizingvolume and known density in milligrams per kilograms asfollows:Sulfur, mg/kg 5M 2 B!V 3 D(2)14.3 Measurement utilizing weight of sample:sulfur, mg/kg 5M 2 B!w(3)where:M = measured sulfur value, gB =
44、 blank measured sulfur value, gV = sample injection volume, mLD = density of sample g/mLw = weight of sample, g15. Report15.1 Report the sulfur results as (mg/kg ) of the sample tothe nearest 0.01 mg/kg for samples less than 1 mg/kg. Reportto the nearest .1 for sample greater than 1 mg/kg.16. Precis
45、ion and Bias516.1 The precision of this test method is based on guidelinesof Practice E691, an interlaboratory study determination ofTotal Sulfur in Aromatic Hydrocarbons and Related Chemicalsby Ultraviolet Fluorescence, conducted in 2004. Each of 19laboratories tested 5 different materials for sulf
46、ur concentra-tions between 0.05 and 0.9 mg/kg (Table 1). Results for5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D16-1035. ContactASTM CustomerService at serviceastm.org.TABLE 1 Sulfur Concentrations Between 0.05 and 0.9 mg/k
47、gMaterialAverageXRepeatabilityLimitrReproducibilityLimitRBlank 0.051 . .+0.498 0.500 0.083 0.216+0.892 0.850 0.063 0.280D7183 153materials containing 0.05 and 0.1 mg/kg were dropped due tohigh variability. In a corresponding effort, 25 laboratoriesjoined in the evaluation of 3 materials with sulfur
48、concentra-tions between 15 and 90 mg/kg (Table 2). Each test result wasaverage of 3 individual determinations. Participating laborato-ries reported 3 replicate test results for each material. Allsamples were prepared from high purity p-xylene with knownquantities of sulfur added.16.1.1 Repeatability
49、Two test results obtained within onelaboratory shall be judged not equivalent if they differ by morethan the “r” value for that material; “r” is the intervalrepresenting the critical difference between two test results forthe same material, obtained by the same operator using thesame equipment on the same day in the same laboratory.16.1.2 ReproducibilityTwo test results should be judgednot equivalent if they differ by more than the “R” value for thatmaterial; “R” is the interval representing the difference be-tween two test resul
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