ASTM D7319-2011e1 7500 Standard Test Method for Determination of Existent and Potential Sulfate and Inorganic Chloride in Fuel Ethanol by Direct Injection Suppressed Ion Chromatogr.pdf

1、Designation: D7319 111Standard 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 t

2、he 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.1NOTEUpdated 13.1 editorially in October 2011.1. Scope*1.1 Th

3、is test method covers a direct injection ion chromato-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 samplescon

4、taining between 1.020 mg/kg of existent or potentialinorganic 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 conce

5、rns, 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. Material SafetyData Sheets are available for reagents and materials. Reviewthem fo

6、r hazards prior to usage.2. Referenced Documents2.1 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 Automati

7、c Sampling of Petroleum andPetroleum ProductsD5827 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

8、for Quality System in Petroleum Productsand Lubricants Testing LaboratoriesD7318 Test Method for Existent Inorganic Sulfate in Etha-nol by Potentiometric TitrationD7328 Test Method for Determination of Existent andPotential Inorganic Sulfate and Total Inorganic Chloride inFuel Ethanol by Ion Chromat

9、ography Using AqueousSample Injection2.2 European 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,

10、 ninorganic sulfate speciesactually present in 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 presentas sulfuric acid, io

11、nic salts of this acid, or mixtures of these.3.1.4 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 in

12、to a suitablyconfigured ion chromatograph in accordance with manufactur-ers recommendations for this test method. For potentialsulfate, 0.5 mL of 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 af

13、finity forexchange sites of the resin with respect 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 July 1, 2011. Publi

14、shed August 2011. Originallyapproved in 2007. Last previous edition approved in 2009 as D731909. DOI:10.1520/D7319-11.2For 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 t

15、o the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Dri

16、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.the 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 hydro

17、gen forms ofanions. Anions are quantified by integration 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

18、 is moresignificant for the precision of sulfate 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 an

19、d potential inorganicsulfate by ion chromatography 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 an

20、d chlorides can be found in filter pluggingdeposits 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,

21、 can be used asone measure of the acceptability 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 in

22、terest. Sampledilution can be used to minimize 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 an

23、d sulfate peaks are faraway from the water dip.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

24、low sulfate results. Take care to ensure thatcontamination 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

25、 110 6 5C for dryingsodium sulfate and sodium chloride.7.3 Desiccator, containing freshly activated silica gel (orequivalent desiccant) with moisture content indicator.7.4 Pipets or Volumetric Transferring Devices, appropri-ately sized Class A glass pipets or their equivalent or variablevolume autom

26、atic pipets fitted with disposable polypropylenetips.NOTEChromatogram 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 WaterD7319 11127.5 Volumetric Flasks (with Glass Stoppers), Class A of

27、10,25, 50, 100, 1000, 2000cc capacity.7.5.1 Container, 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.

28、6.1 Injection System, capable of delivering 20 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 determin

29、ation by the manu-facturer.7.6.3 Guard Column, 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 an

30、dchloride) separation (Fig. 1).7.6.5 Anion Suppressor 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-li

31、ne continuously chemically regenerated to its hydrogen formusing any mineral acid providing H+ ion.7.6.5.2 Continuous Approach, Continuous suppressor mem-brane regeneration.7.6.6 Conductivity Detector, (low volume), temperaturecontrolled to 0.01C, capable of at least 0 to 1000 S/cm on alinear scale.

32、7.6.7 Integrator or Chromatography Data System Software,capable of measuring 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 sha

33、ll be used for the preparation of all samples,standards, eluent, and 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

34、grades may be used, provided it is firstascertained that the reagent 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

35、 better in Specification D1193. For eluentpreparation and handling, comply 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.Disso

36、lve 8.4 6 0.0005 g of NaHCO3and 33.92 6 0.0005 g ofNa2CO3in reagent water 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 oranalyti

37、cal columns are used.NOTE 1Other volumes of stock solution can be prepared 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 Sol

38、ution for Suppressor0.1 Msulfuric acid. Carefully add 334 mL of reagent 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 conce

39、ntrated acid.) Dilute to 1000mL with reagent water, and label this solution 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 using appro-priate ratios of reagent

40、s. Follow the specific guidelines for this solutionfrom the vendor of the 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

41、methanol, formula 3A or his-tological grade ethanol, anhydrous, denatured with ethyl ac-etate, 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 Hy

42、drogen Peroxide Solution, 30 %commerciallyavailable 30 % hydrogen peroxide solution.9. 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 least an hour, cool,

43、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 Eq 1. Other volume

44、s of stocksolution can be prepared using the appropriate ratio of re-agents.Stock Sulfate mg/L!5gNa2SO4!0.6764!1000 mg/g!/1 L (1)4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the America

45、n Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D7319 1113where:gNa2SO4= weight in grams of Na2SO4dissolved in 1 L,and0.6764 = weight pe

46、rcent sulfate in Na2SO4.9.1.2 Chloride Stock Solution (approximately 2000 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

47、 a 1Lvolumetric flask. Add water to dissolve the sodium chlorideand make 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!5g NaCl!0.6068!1000 mg/g!/1

48、L (2)where:g NaCl = weight in grams of NaCl dissolved in 1 L, and0.6068 = 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

49、.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 sulfate and chloride concentrations of eachstandard are calculated in accordance with Eq 3 and Eq 4.Sulfate in Standard mg/L!5Va3 Ca/ V (3)Chloride in Standard mg/L!5Vb3 Cb/ V (4)where:Va= volume of sulfate stock solution (9.