ASTM D7319-2012 3178 Standard Test Method for Determination of Existent and Potential Sulfate and Inorganic Chloride in Fuel Ethanol by Direct Injection Suppressed Ion Chromatograp.pdf

1、Designation: D7319 12Standard Test Method forDetermination of Existent and Potential Sulfate andInorganic Chloride in Fuel Ethanol by Direct InjectionSuppressed Ion Chromatography1This standard is issued under the fixed designation D7319; the number immediately following the designation indicates th

2、e 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. Scope*1.1 This test method covers a direct injection ion ch

3、romato-graphic procedure for determining existent and potential inor-ganic sulfate and total inorganic chloride content in hydrousand anhydrous denatured ethanol to be used in motor fuelapplications. It is intended for the analysis of ethanol samplescontaining between 1.020 mg/kg of existent or pote

4、ntialinorganic sulfate and 1.050 mg/kg of inorganic chloride.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the

5、responsibility 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. Material SafetyData Sheets are available for reagents and materials. Reviewthem for hazards prior to usage.2. Referenced Document

6、s2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD5

7、827 Test Method for Analysis of Engine Coolant forChloride and Other Anions by Ion ChromatographyD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality System in Petroleum Productsand Lub

8、ricants Testing LaboratoriesD7318 Test Method for Existent Inorganic Sulfate in Ethanolby Potentiometric TitrationD7328 Test Method for Determination of Existent and Po-tential Inorganic Sulfate and Total Inorganic Chloride inFuel Ethanol by Ion Chromatography Using AqueousSample Injection2.2 Europe

9、an Norm Standards:3EN 15492 Ethanol as a blending component for petrol -Determination of inorganic chloride and sulfate content -Ion chromatographic method3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 existent inorganic sulfate, ninorganic sulfate speciesactually present in

10、the sample at the time of analysis with nooxidation treatment.3.1.2 inorganic chloride, nchloride present as hydrochlo-ric acid, ionic salts of this acid, or mixtures of these.3.1.3 inorganic sulfate, nsulfate (SO4-2) species present assulfuric acid, ionic salts of this acid, or mixtures of these.3.

11、1.4 potential sulfate, ninorganic sulfate species presentafter the sample has been reacted with an oxidizing agent.4. Summary of Test Method4.1 For existent inorganic sulfate and total chloride, a smallvolume of an ethanol sample is directly injected into a suitablyconfigured ion chromatograph in ac

12、cordance with manufactur-ers recommendations for this test method. For potentialsulfate, 0.5 mLof 30?% hydrogen peroxide solution is added to9.5 mL of the ethanol sample, and then injected into the ionchromatograph. Ions are separated based on their affinity forexchange sites of the resin with respe

13、ct to the resins affinity for1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved Dec. 1, 2012. Published December 2012. Originallyapproved in 2007.

14、Last previous edition approved in 2011 as D7319111. DOI:10.1520/D7319-12.2For 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 A

15、STM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29

16、59. United States1the eluent. The suppressor increases the sensitivity of the testmethod by both increasing the conductivity of the analytes anddecreasing the conductivity of the eluent. It also converts theeluent and analytes to the corresponding hydrogen forms ofanions. Anions are quantified by in

17、tegration of their responsescompared with an external calibration curve, and are measuredas milligrams/litre, then converted to milligrams/kilograms.The calibration standards are prepared in an aqueous matrix.4.1.1 The use of acid suppression technology is moresignificant for the precision of sulfat

18、e measurement than forchloride. Sulfate precision will be worse if acid suppression isnot used.4.2 Similar methods for chloride and sulfate determinationscan be found in EN 15492 for total chloride, in Test MethodD7328 for total chloride and existent and potential inorganicsulfate by ion chromatogra

19、phy with aqueous sample injection,and in Test Method D7318 for existent inorganic sulfate bypotentiometric lead titration and Test Method D5827 forchloride and other anions in engine coolants by ion chroma-tography.5. Significance and Use5.1 Sulfates and chlorides can be found in filter pluggingdepo

20、sits and fuel injector deposits. The acceptability for use ofthe fuel components and the finished fuels depends on thesulfate and chloride content.5.2 Existent and potential inorganic sulfate and total chlo-ride content, as measured by this test method, can be used asone measure of the acceptability

21、 of gasoline components forautomotive spark-ignition engine fuel use.6. Interferences6.1 Interferences can be caused by substances with similarion chromatographic retention times, especially if they are inhigh concentration compared to the analyte of interest. Sampledilution can be used to minimize

22、or resolve most interferenceproblems.6.2 A water dip (system void, negative peak as shown inFig. 1) can cause interference with some integrators. Usually,for chloride and sulfate determinations, the water dip shouldnot be a problem since the chloride and sulfate peaks are faraway from the water dip.

23、6.3 Given the trace amounts of chloride and sulfate deter-mined in this test method, interferences can be caused bycontamination of glassware, eluent, reagents, and the like. Forexample, sodium leaching from glassware can precipitate withsulfate giving low sulfate results. Take care to ensure thatco

24、ntamination is kept at the lowest possible levels. The use ofpowder-free gloves is highly recommended to prevent samplecontamination.7. Apparatus7.1 Analytical Balance, capable of weighing up to 100 gaccurately to 0.0001 g.7.2 Drying Oven, controlled at 110 6 5C for dryingsodium sulfate and sodium c

25、hloride.7.3 Desiccator, containing freshly activated silica gel (orequivalent desiccant) with moisture content indicator.NOTE 1Chromatogram retention times may be different depending on instruments or columns used.FIG. 1 Typical Ion Chromatogram of a Solution Containing 1 mg/L of Various Anions in W

26、aterD7319 1227.4 Pipets or Volumetric Transferring Devices, appropri-ately sized Class A glass pipets or their equivalent or variablevolume automatic pipets fitted with disposable polypropylenetips.7.5 Volumetric Flasks (with Glass Stoppers), Class A of 10,25, 50, 100, 1000, 2000cc capacity.7.5.1 Co

27、ntainer, equipped with a closure to prevent ethanolevaporation, 1 L (for sample collection). See 6.3 for additionalinformation.7.6 Ion Chromatograph, analytical system with all requiredaccessories including syringes, columns, suppressor, and de-tector.7.6.1 Injection System, capable of delivering 20

28、 L with aprecision better than 1?%, or as recommended for this deter-mination by the manufacturer.7.6.2 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.7.6.3 Guard Column,

29、 for protection of the analytical columnfrom strongly retained constituents. Better separations areobtained with additional theoretical plates.7.6.4 Anion Separator Column, 100?% solvent compatibleand capable of producing satisfactory analyte (sulfate andchloride) separation (Fig. 1).7.6.5 Anion Sup

30、pressor Device, vendor specific and capableof using acid suppression technology.7.6.5.1 Tri-Chamber Approach, 100?% solvent compatibletri-chamber micro packed bed with cation exchange resin (orequivalent). Suppressor device should simultaneously be on-line continuously chemically regenerated to its

31、hydrogen formusing any mineral acid providing H+ ion.7.6.5.2 Continuous Approach, The regenerant channels areflushed with a mineral acid (sulfuric) to supply hydronium ionsrequired for the suppression reaction. The solvent ?compatibleion exchange membranes provide the transport pathway for thehydron

32、ium ions into the eluent channel and the transport ofsodium and other cations out of the eluent channel.7.6.6 Conductivity Detector, (low volume), temperaturecontrolled to 0.01C, capable of at least 0 to 1000 S/cm on alinear scale.7.6.7 Integrator or Chromatography Data System Software,capable of me

33、asuring peak areas and retention times, andcorrecting the data in accordance with the baseline of thechromatogram.7.7 Gloves, powder-free examination type.8. Reagents8.1 Purity of ReagentsReagent grade or higher puritychemicals shall be used for the preparation of all samples,standards, eluent, and

34、regenerator solutions. Unless otherwiseindicated, it is intended that all reagents conform to thespecifications of the Committee on Analytical Reagents of theAmerican Chemical Society, where such specifications areavailable.4Other grades may be used, provided it is firstascertained that the reagent

35、is of sufficiently high purity topermit its use without lessening the accuracy of the determi-nation.8.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water as definedby Type II or better in Specification D1193. For eluentpreparation and handling, c

36、omply with all ion chromatographinstrument and column vendor requirements (for example,filtering, degassing, and the like).8.3 Eluent Buffer Stock SolutionSodium bicarbonate(NaHCO3) 1.0 mM and sodium carbonate (Na2CO3) 3.2 mM.Dissolve 8.4 6 0.0005 g of NaHCO3and 33.92 6 0.0005 g ofNa2CO3in reagent w

37、ater in a 1-L Type A volumetric flask anddilute to volume. Dilute 10.0 mL of this stock solution to 1 Lin a 1-L Type A volumetric flask with degassed reagent water.The eluent solution used may be different if other system oranalytical columns are used.NOTE 1Other volumes of stock solution can be pre

38、pared usingappropriate ratios of reagents. Follow the specific guidelines for thissolution from the vendor of the column being used. Alternatively, thissolution can be purchased from a qualified vendor.8.4 Suppressor Regenerant Solution for Suppressor0.1 Msulfuric acid. Carefully add 334 mL of reage

39、nt grade sulfuricacid (relative density 1.84) to approximately 500 mL reagentwater in a 1-L volumetric flask. (WarningThis will generatea very hot solution.Allow it to cool before diluting to 1000 mLvolume. Never add water to concentrated acid.) Dilute to 1000mL with reagent water, and label this so

40、lution as 10.0 Msulfuric acid. Dilute 10.0 mL of this concentrate to 1000 mLwith reagent water for the final 0.1 M working suppressorsolution.NOTE 2Other volumes of this solution can be prepared usingappropriate ratios of reagents. Follow the specific guidelines for thissolution from the vendor of t

41、he suppressor being used.8.5 Sodium Sulfateanhydrous, reagent grade, 99?% mini-mum purity. (WarningDo not ingest. Avoid unnecessaryexposure.)8.6 Sodium ChlorideACS or reagent grade, 99?% mini-mum purity.8.7 Ethanoldenatured with methanol, formula 3A or his-tological grade ethanol, anhydrous, denatur

42、ed with ethylacetate, methylisobutyl ketone and hydrocarbon naphtha.(WarningFlammable, toxic, and may be harmful or fatal ifingested or inhaled. Avoid skin contact.)8.8 Hydrogen PeroxideACS reagent grade, 30 wt % inwater.8.9 Hydrogen Peroxide Solution, 30?%commerciallyavailable 30?% hydrogen peroxid

43、e solution.4Reagent Chemicals, American Chemical Society Specifications, 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

44、 Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D7319 1239. Preparation of Standard Solutions9.1 Stock Solutions:9.1.1 Sulfate Stock Solution, approximately 2000 mg/LToensure dryness, place anhydrous sodium sulfate (5 g) in adrying oven at 110C for at le

45、ast an hour, cool, and store in adesiccator. Accurately weigh 2.96 g anhydrous sodium sulfateto the nearest tenth of a milligram and transfer to a 1Lvolumetric flask. Add water to dissolve the sodium sulfate, andmake to volume. Calculate the concentration of sulfate in thesolution in accordance with

46、 Eq 1. Other volumes of stocksolution can be prepared using the appropriate ratio of re-agents.Stock Sulfate mg/L! 5 gNa2SO4!0.6764!1000 mg/g!/1 L (1)where:gNa2SO4= weight in grams of Na2SO4dissolved in 1 L,and0.6764 = weight percent sulfate in Na2SO4.9.1.2 Chloride Stock Solution (approximately 200

47、0 mg/L)To ensure dryness, place sodium chloride (5 g) in a dryingoven at 110C for at least an hour, cool, and store in adesiccator. Accurately weigh 3.30 g dried sodium chloride tothe nearest tenth of a milligram and transfer to a 1Lvolumetric flask. Add water to dissolve the sodium chlorideand make

48、 to volume. Calculate the concentration of chloride inthe solution in accordance with Eq 2. Other volumes of stocksolution can be prepared using the appropriate ratio of re-agents.Stock Chloride mg/L! 5 g NaCl!0.6068!1000 mg/g!/1 L (2)where:g NaCl = weight in grams of NaCl dissolved in 1 L, and0.606

49、8 = weight percent chloride in NaCl.9.2 Chloride and Sulfate Standards in WaterAdd waterand sulfate and chloride stock solutions are added to a 1Lglass volumetric flask in accordance with Table 1 to achievethe desired standard.9.2.1 Chloride and sulfate stock solutions from 9.1 areadded quantitatively into the flask and mixed quantitativelywith water in accordance with Table 1. Be very careful tomeasure the exact volumes of the sulfate and chloride stocksolutions that are added to the flask, and fill the flask to 1.00 Lwith water. The s