1、Designation: D7183 16Standard 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 10 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 for
4、 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 limitations
6、 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 Contro
7、l 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 region
9、 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 dioxi
10、de(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 i
11、s 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 fee
12、dstocks. 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 responsibili
13、ty ofSubcommittee D16.04 on Instrumental Analysis.Current edition approved June 1, 2016. Published July 2016. Originally approvedin 2007. Last previous edition approved in 2015 as D7183 15. DOI: 10.1520/D7183-16.2For 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 concent
16、rations of 1500 mg/kg orgreater can interfere.6.2 Moisture produced during the combustion step caninterfere if not removed prior to the gas entering the detectorcell.7. Apparatus7.1 Combustion FurnaceAn electric furnace capable ofmaintaining a temperature sufficient to volatilize and combustall the
17、sample and oxidize sulfur to SO2. The actual tempera-ture should be recommended by specific instrument manufac-turer.7.2 Quartz Combustion TubeCapable of withstanding 900to 1200C. 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 with ameans of flow control capable of maint
20、aining a constant supplyof oxygen and carrier gas or air.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
21、 the Committee 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 d
22、etermination.8.2 Inert Gas or AirEither argon (Ar), helium (He) or airmay be used. The purity should be no less than 99.99%.8.3 Oxygen Gas (as required)The purity should be no lessthan 99.99%.8.4 SolventThe solvent chosen should be capable ofdissolving the sulfur compound. The solvent of choice shou
23、ldhave a boiling point similar 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
24、2All solvents should have known 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 8
25、70 to 1044 gS/mlThis standard 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 c
26、oncentrationof stock solution. 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
27、ml of Solvent(1)where:DBT = 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.8.8
28、Oxidation Reagent (as required)Tungsten trioxide,(WO3), granular (typical particle size 2.0 mm), high purity,99.75% minimum.9. Hazards9.1 Consult the current version OSHA regulations, suppli-ers Safety Data Sheets, and local regulations for all materialsused in this test method.9.2 High temperature
29、is employed in this test method. Extracare must be exercised when using flammable materials nearthe furnace.9.3 WarningExposure to excessive quantities of ultravio-let light is injurious to health. The operator must avoidexposing any part of their person, especially their eyes, notonly to direct UV
30、light but also to secondary or scatteredradiation that is present.10. Sampling10.1 Consult guidelines for taking samples from bulk con-tainers in accordance with Practice D3437.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on
31、the testing of reagents notlisted by the American 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 16211. Preparation of Apparatus11.
32、1 Set-up the instrument in accordance with manufactur-ers instructions.11.2 Adjust gas flows and pyrolysis temperature(s) to theoperating conditions recommended by the manufacturer.11.3 The actual operation of injecting a sample will varydepending upon the instrument manufacturer and the type ofinle
33、t 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 sample boats to be used for the determi-nation when using a horizontal furnace.12. Calibration and Standardization12.1 Using the sulfur standard stock
34、solution (see 8.7),make a series of calibrations standards covering the range ofexpected sulfur concentration.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 solution, to cover the e
35、xpectedrange of samples. Follow manufacturers recommendations for construct-ing the curve.NOTE 7When looking for concentrations from 1 mg S/kg to 10 mgS/kg, follow manufacturers recommendations for constructing the curve.12.2 The sample size can be determined eithervolumetrically, by syringe or by m
36、ass.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 in the syringe.
37、 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 sampleinjected. This techni
38、que 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 standardsfollow the instrument
39、 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 pointon the curve t
40、o 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 than the concen
41、tration 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 average ofthree determ
42、inations, 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 the instrument to
43、 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 = blank measured
44、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. Precision and Bias516.
45、1 An ILS was conducted which included eleven labora-tories analyzing ten samples two times. Practice E691 wasfollowed for the design and analysis of the data; the details aregiven in ASTM Research Report RR:D16-1060.16.1.1 Repeatability Limit (r)Results should not be sus-pect unless they differ by m
46、ore than shown in Table 1. Resultsdiffering by less than (r) have a 95% probability of beingcorrect.16.1.2 Reproducibility Limit (R)Results submitted by twolaboratories should not be considered suspect unless they differby more than shown in Table 1. Results differing by less thanR have a 95% probab
47、ility of being correct.16.2 BiasAt this time of the study, no accepted referencematerial suitable for determining the bias for this test methodwas utilized, therefore no statement on bias is being made.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesti
48、ng Research Report RR:D16-1060. ContactASTM CustomerService at serviceastm.org.D7183 16317. Quality Assurance and Quality Control17.1 Refer to Guide D6809 for suggested QA/QC activitiesthat can be used as a part of this test method. It is recom-mended that the operator of this test method select and
49、 performrelevant QA/QC activities like the ones in Guide D6809 to helpensure the quality of data generated by this test method.18. Keywords18.1 aromatics; fluorescence; hydrocarbons; sulfur; ultra-violetAPPENDIX(Nonmandatory Information)X1. OPERATIONAL CONDITIONS FOR SUCCESSFUL TRACE SULFUR ANALYSISX1.1 This method may be used to successfully analyzeconcentrations below the current scope. Careful analyticaltechnique and adherence to the instrument manufacturersinstructions and recommendations can yield analysis to tracelevels d
