1、Designation: D7359 14aStandard Test Method forTotal Fluorine, Chlorine and Sulfur in AromaticHydrocarbons and Their Mixtures by OxidativePyrohydrolytic Combustion followed by IonChromatography Detection (Combustion IonChromatography-CIC)1This standard is issued under the fixed designation D7359; the
2、 number immediately following the designation indicates the year oforiginal adoption 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. S
3、cope*1.1 This test method covers the individual determination oftotal fluorine, chlorine and sulfur in aromatic hydrocarbons andtheir mixtures. Samples containing 0.10 to 10 mg/kg of eachelement can be analyzed.1.2 This method can be applied to sample concentrationsoutside the range of the scope by
4、dilution of the sample in anappropriate solvent to bring the total concentrations of fluorine,chlorine and sulfur within the range covered by the testmethod. However, it is the responsibility of the analyst toverify the solubility of the sample in the solvent and that thediluted sample results confo
5、rm to the precision and accuracy ofthe method.1.2.1 Special considerations must be made in order to attaindetection limits below 1.0 mg/kg in a sample. The instrumentmust be clean and properly maintained to address potentialsources of contamination, or carryover, or both. Multiplesequential injectio
6、ns shall be completed until a stable back-ground is attained. A stable background is considered to beachieved when the analysis of a minimum of three consecutivesystem blanks have area counts equal to or less than 5 % RSDfor the anions of interest.1.3 In determining the conformance of the test resul
7、ts usingthis method to applicable specifications, results shall berounded off in accordance with the rounding-off method ofPractice E29.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to ad
8、dress 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 prior to use. See Section 9.2. Referenced Documents2.1 ASTM Standard
9、s:2D1193 Specification for Reagent WaterD3437 Practice for Sampling and Handling Liquid CyclicProductsD3505 Test Method for Density or Relative Density of PureLiquid ChemicalsD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice
10、for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE288 Specification for Laboratory Glass Volumetric FlasksE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a
11、Test MethodE969 Specification for Glass Volumetric (Transfer) Pipets2.2 Other Documents:OSHA Regulations, 29 CFR paragraphs 1910.1000 and1910.120033. Terminology3.1 Definitions:3.1.1 combustion ion chromatography, nan analytical sys-tem consisting of pyrohydrolytic combustion followed by ionchromato
12、graphic detection.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.04 on Instrumental Analysis.Current edition approved Dec. 1, 2014. Published January 2015. Originallyapproved in 2008.
13、 Last previous edition approved in 2014 as D7359 14. DOI:10.1520/D7359-14A.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
14、 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.access.gpo.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Bo
15、x C700, West Conshohocken, PA 19428-2959. United States13.1.2 oxidative pyrohydrolytic combustion, na process inwhich a sample undergoes combustion at temperatures greaterthan 900C in an oxygen rich environment and in the presenceof excess water vapor not originating from the combustion ofthe sample
16、. In oxidative pyrohydrolytic combustion, thesample is pyrolyzed into carbon dioxide, water, hydrogenhalides and residual ash; typically elemental oxides.3.1.3 halogens (X), nthe elements fluorine, chlorine, bro-mine and iodine.3.1.4 hydrogen halide (HX), nare inorganic compoundswith the formula HX
17、where X is one of the halogens: fluorine,chlorine, bromine, and iodine. Hydrogen halides are gases thatdissolve in water to give acids.3.1.5 sulfur oxide (SOx), nrefers to one or more of thefollowing compounds:3.1.5.1 sulfur dioxide (SO2)3.1.5.2 sulfur trioxide (SO3)3.1.5.3 sulfate (SO4)3.1.6 system
18、 blank, na combustion ion chromatography(CIC) analysis with no solvent or sample injection in which thesame combustion, chromatography and time protocols are usedas for the sample analysis, but without the combustion of asample or solvent blank. The system blank must be equal to orless than 50 % (12
19、) the area counts of the lowest calibrationstandard used for calibration and a maximum of 50 % (1/2) ofthe area count of the solvent blank used in the preparation ofthe calibration standards for the anions of interest.3.1.7 solvent blank, na combustion ion chromatography(CIC) analysis of the solvent
20、 used for preparation of thecalibration standards in which the same combustion,chromatography, time protocols and injection volumes are usedas for the sample analysis. The solvent blank area count mustbe less than or equal to two times (2) the system blank and50 % (1/2) or less than the area counts
21、of the lowest calibrationstandard used in the calibration of the system for the anions ofinterest.3.1.8 stock standard solution, nstandard prepared fromprimary standards and subsequently used to prepare the work-ing standard.3.1.9 working standard solution, nstandard prepared fromthe stock standard
22、solution and subsequently used to preparethe calibration standards.3.1.10 calibration standard, nstandard prepared from theworking standard and subsequently used to calibrate theinstrument.3.2 Abbreviations:3.2.1 CICcombustion ion chromatography3.2.2 Concconcentration3.2.3 CRMcertified reference mat
23、erial3.2.4 HCIhydrogen choloride3.2.5 HFhydrogen fluoride3.2.6 HXhydrogen halide3.2.7 ICion chromatograph or ion chromatography3.2.8 SOxsulfur oxide (SO2and SO3)3.2.9 SO2sulfur dioxide3.2.10 SO3sulfur trioxide3.2.11 SO4sulfate3.2.12 Stdstandard3.2.13 SRMstandard reference material4. Summary of Test
24、Method4.1 A sample of known weight or volume is placed into asample boat and introduced at a controlled rate into a hightemperature combustion tube. There the sample is combustedin an oxygen rich pyrohydrolytic environment. The gaseousby-products of the combusted sample are trapped in anabsorption m
25、edium where the hydrogen halides (HX) formedduring combustion disassociate into their respective ions, X-while the sulfur oxides (SOX) formed are further oxidized toSO42-in the presence of an oxidizing agent. An aliquot ofknown volume of the absorbing solution is then automaticallyinjected into an i
26、on chromatograph (IC) by means of a sampleinjection valve. The halide and sulfate anions are separated onthe anion separation column of the IC. The conductivity of theeluent is reduced with an anion suppression device prior to theion chromatographs conductivity detector, where the anions ofinterest
27、are measured. Quantification of the fluorine, chlorineand sulfur in the original combusted sample is achieved by firstcalibrating the system with a series of standards containingknown amounts of fluorine, chlorine and sulfur and thenanalyzing unknown samples under the same conditions as thestandards
28、. The combined system of pyrohydrolytic combustionfollowed by ion chromatographic detection is referred to asCombustion Ion Chromatography (CIC).5. Significance and Use5.1 The total fluorine, chlorine and sulfur contained inaromatic hydrocarbon matrices can contribute to emissions, beharmful to many
29、 catalytic chemical processes, and lead tocorrosion. This test method can be used to determine totalsulfur and halogens in aromatic hydrocarbons and their mix-tures. The results can be used for compliance determinationswhen acceptable to a regulatory authority using performancebased criteria.6. Inte
30、rferences6.1 Substances that co-elute with the anions of interest willinterfere. A high concentration of one anion can interfere withother constituents if their retention times are close enough toaffect the resolution of their peak.7. Apparatus7.1 Autosampler, capable of accurately delivering a know
31、nvolume of sample, typically in the range of 10 to 100 L, intothe sample boat.NOTE 1The sample syringe should be rinsed with clean solventfollowed by a rinse with the next sample when changing from one vial toanother. Follow the manufacturers recommendation to minimize carry-over.7.2 Balance, analyt
32、ical, with sensitivity to 0.0001 g.D7359 14a27.3 Boat Inlet SystemThe system provides a sampling portfor the introduction of liquid samples into the sample boat andis connected to the inlet of the combustion tube. The system isswept by a humidified inert carrier gas and shall be capable ofallowing t
33、he quantitative delivery of the material to be ana-lyzed into the oxidation zone at a controlled rate.7.4 Boat Inlet CoolerSample volatility requires an appa-ratus capable of cooling the sample boat prior to sampleinjection into the boat.7.5 Gas Flow ControlThe apparatus must be equippedwith flow co
34、ntrollers capable of maintaining a constant flow ofoxygen and argon or helium carrier gas.7.6 FurnaceAn electric furnace which can maintain aminimum temperature of 900C.7.7 Gas Absorption Unit, having an absorption tube withsufficient capacity to hold a minimum of 5 mL which isautomatically filled w
35、ith a known volume of absorption solu-tion by a built-in burette or other similar device. The gasabsorption unit is interfaced to the IC and injects an aliquot ofthe absorption solution into the IC after the sample is com-busted and the by-products of combustion are absorbed. Thegas absorption unit
36、rinses the absorption tube and the transferlines from the combustion tube to the gas absorption unit withType I reagent water (8.2) or other appropriate absorptionsolution prior to sample combustion and after the absorptionsolution is injected into the IC to minimize cross contamina-tion.7.8 Gas-Tig
37、ht Sampling Syringe, of 10, 25, 50, 100, or 250-L capacity and capable of accurately delivering microliterquantities.7.9 Pyrohydrolytic Combustion Tube made of quartz andcapable of withstanding temperatures up to 1100C. Thecombustion tube must be of ample volume and may includequartz wool or other s
38、uitable medium to provide sufficientmixing and surface area to ensure complete combustion of thesample.7.10 Humidifier Delivery System, capable of deliveringType 1 reagent water (8.2) to the combustion tube at acontrolled rate sufficient to provide a pyrohydrolytic environ-ment.7.11 Ion Chromatograp
39、h (IC),4an analytical system with allrequired accessories including columns, suppressor and detec-tor.7.11.1 Injection System, capable of delivering 20 to 500 Lwith a precision better than 1 % or as recommended for thisdetermination by the manufacturer. Larger volumes can beused as long as the perfo
40、rmance criteria of the method are notdegraded.7.11.2 Pumping System, capable of delivering mobile phaseflows between 0.2 and 2.5 mL/min with a precision better than2 %, or as recommended for this determination by the manu-facturer.7.11.3 Continuous Eluent Generation (optional), to auto-matically pre
41、pare and purify the eluent used in the ionchromatography. Electrolytic eluent generation and auto-buretpreparation of eluent by means of in-line dilution of a stocksolution have been found satisfactory for this method. Othercontinuous eluent generation devices may be used if theprecision and accurac
42、y of the method are not degraded.7.11.4 Anion Pre-concentration Column (optional), used foranion pre-concentration and matrix elimination. Pre-concentration enables larger volumes of absorbing solu-tion (1 to 3 mL) to be analyzed without the associated waterdip. Matrix elimination refers to the elim
43、ination of anyunreacted hydrogen peroxide in the absorbing solution prior toinjection onto the guard and anion separator columns andpotentially interfere with the fluoride peak resolution.7.11.5 Guard Column, for protection of the analytical col-umn from strongly retained constituents. Improved sepa
44、rationis obtained with additional theoretical plates.7.11.6 Anion Separator Column, capable of producing sat-isfactory baseline separations of the anion peaks of interest asshown in Fig. 1.7.11.7 Anion Suppressor Device, reduces the backgroundconductivity of the eluent after separation by the anions
45、eparator column. Both chemical and continuous electrolyticsuppressors have been found satisfactory for this method.Other anion suppressor devices may be used as long as theprecision and accuracy of the method are not degraded.7.11.8 Conductivity Detector, temperature controlled to0.01C, capable of a
46、t least 0 to 1000 S/cm on a linear scale.7.11.9 Data Acquisition System, an integrator or computerdata handling system capable of integrating the peak areas ofion chromatograph7.12 Quartz or Ceramic Sample Boats of sufficient size tohold 10 to 100 L. The boat is filled with quartz wool or othersuita
47、ble material (8.3) to wick any remaining drops of thesample from the tip of the syringe needle prior to introductionof the sample into the furnace.8. Reagents and Materials8.1 Purity of ReagentsReagent grade or higher puritychemicals shall be used for the preparation of all samples,standards, eluent
48、, and regenerator solutions. Unless otherwiseindicated, it is intended that all reagents shall conform to thespecification of the Committee on Analytical Reagents of theAmerican Chemical Society, where such specifications areavailable.5Other grades may be used, provided that the reagentis of suffici
49、ently high purity to permit its use without lesseningthe accuracy of the determination.NOTE 2Purity of reagents are of particular importance when perform-ing trace analysis (samples containing 1 mg/kg or less in analyteconcentration). A system reagent blank should provide a chromatographicarea response no greater than 50 % (1/2) of the lowest calibrationstandard.4Many different companies manufacture automatic ion chromatographs. Consultthe specific manufacturer instruction manuals for details regarding setup andoperation.5Reagent Chemicals
