1、Designation: D7319 09Standard Test Method forDetermination of Total and Potential Sulfate and InorganicChloride in Fuel Ethanol by Direct Injection Suppressed IonChromatography1This standard is issued under the fixed designation D7319; the number immediately following the designation indicates the y
2、ear 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 chrom
3、ato-graphic procedure for determining the total and potentialinorganic sulfate and total inorganic chloride content in hy-drous and anhydrous denatured ethanol to be used in motor fuelapplications. It is intended for the analysis of ethanol samplescontaining between 1.020 mg/kg of total or potential
4、 inor-ganic 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 theres
5、ponsibility 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 Documents2.
6、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 ProductsD5827
7、 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 Lubric
8、ants Testing LaboratoriesD7318 Test Method for Total Inorganic Sulfate in Ethanolby Potentiometric TitrationD7328 Test Method for Determination of Total and Poten-tial Inorganic Sulfate and Total Inorganic Chloride in FuelEthanol by Ion Chromatography Using Aqueous SampleInjection2.2 European Norm S
9、tandards: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 inorganic chloride, nchloride present as hydrochlo-ric acid, ionic salts of this ac
10、id, or mixtures of these.3.1.2 inorganic sulfate, nsulfate (SO4-2) species presentas sulfuric acid, ionic salts of this acid, or mixtures of these.3.1.3 potential sulfate, ninorganic sulfate species presentafter the sample has been reacted with an oxidizing agent.3.1.4 total sulfate, ninorganic sulf
11、ate species actuallypresent in the sample at the time of analysis with no oxidationtreatment.4. Summary of Test Method4.1 For total sulfate and chloride, a small volume of anethanol sample is directly injected into a suitably configuredion chromatograph in accordance with manufacturers recom-mendati
12、ons for this test method. For potential sulfate, 0.5 mLof 30 % hydrogen peroxide solution is added to 9.5 mL of theethanol sample, and then injected into the ion chromatograph.Ions are separated based on their affinity for exchange sites ofthe resin with respect to the resins affinity for the eluent
13、. Thesuppressor increases the sensitivity of the test method by bothincreasing the conductivity of the analytes and decreasing theconductivity of the eluent. It also converts the eluent andanalytes to the corresponding hydrogen forms of anions.1This test method is under the jurisdiction of ASTM Comm
14、ittee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved Nov. 1, 2009. Published December 2009. Originallyapproved in 2007. Last previous edition approved in 2007 as D731907. DOI:10.1520/D7319-09.2For referenc
15、ed 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 ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd S
16、t.,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 Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Anions are quantified by integration of their responses com-pared
17、with an external calibration curve, and are measured asmilligrams/litre, then converted to milligrams/kilograms. Thecalibration standards are prepared in an aqueous matrix.4.1.1 The use of acid suppression technology is moresignificant for the precision of sulfate measurement than forchloride. Sulfa
18、te 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 total and potential sulfate by ionchromatography with aqueous sample injection, and in TestMeth
19、od D7318 for total sulfate by potentiometric lead titrationand Test Method D5827 for chloride and other anions in enginecoolants by ion chromatography.5. Significance and Use5.1 Sulfates and chlorides can be found in filter pluggingdeposits and fuel injector deposits. The acceptability for use ofthe
20、 fuel components and the finished fuels depends on thesulfate and chloride content.5.2 Total and potential sulfate and total chloride content, asmeasured by this test method, can be used as one measure ofthe acceptability of gasoline components for automotive spark-ignition engine fuel use.6. Interf
21、erences6.1 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 or resolve most interferenceproblems.6.2 A water dip (system void, negative pe
22、ak 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.6.3 Given the trace amounts of chloride and sulfate deter-mined in this test m
23、ethod, 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 thatcontamination is kept at the lowest possible levels. The use ofpowder-free glove
24、s 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 chloride.7.3 Desiccator, containing freshly activated silica gel (orequivalent
25、desiccant) with moisture content indicator.7.4 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,
26、1000, 2000cc capacity.7.5.1 Container, equipped with a closure to prevent ethanolevaporation, 1 L (for sample collection). See 6.3 for additionalinformation.NOTEChromatogram retention times may be different depending on instruments or columns used.FIG. 1 Typical Ion Chromatogram of a Solution Contai
27、ning 1 mg/L of Various Anions in WaterD7319 0927.6 Ion Chromatograph, analytical system with all requiredaccessories including syringes, columns, suppressor, and de-tector.7.6.1 Injection System, capable of delivering 20 L with aprecision better than 1 %, or as recommended for this deter-mination by
28、 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, for protection of the analytical columnfrom strongly retained constituents. Bet
29、ter 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 Suppressor Device, vendor specific and capableof using acid suppression technology.
30、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 hydrogen formusing any mineral acid providing H+ ion.7.6.5.2 Continuous Approach
31、, 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.7.6.7 Integrator or Chromatography Data System Software,capable of measuring peak areas and retention times, andcorrecting the
32、 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 regenerator solutions. Unless otherwiseindicated, it is i
33、ntended 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 is of sufficiently high purity topermit its use without l
34、essening 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, comply with all ion chromatographinstrument and column ven
35、dor 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 water in a 1-L Type A volumetric flask anddilute to volume
36、. 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 prepared usingappropriate ratios of reagents. Follow the spe
37、cific 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 reagent grade sulfuricacid (relative density 1.84) to approxim
38、ately 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 solution as 10.0 Msulfuric acid. Dilute 10.0 mL of this con
39、centrate 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 reagents. Follow the specific guidelines for this solutionfrom the vendor of the suppressor being used.8.5 Sodium Sulfateanhydrous, r
40、eagent 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, denatured with ethyl ac-etate, methylisobutyl ketone and hydro
41、carbon 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 peroxide solution.9. Preparation of Standard Solutions9.1 St
42、ock 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, and store in adesiccator. Accurately weigh 2.96 g anhydrous sodium sulfateto the nearest tenth of a milligram and transfer to
43、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 volumes of stocksolution can be prepared using the appropriate ratio of re-agents.Stock Sulfate mg/L!5gNa2SO4!0.6764!1000 mg/g!/1 L
44、(1)where:gNa2SO4= weight in grams of Na2SO4dissolved in 1 L,and4Reagent 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,
45、BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D7319 0930.6764 = weight percent sulfate in Na2SO4.9.1.2 Chloride Stock Solution (approximately 2000 mg/L)To ensure dryness, place sodium chloride (5 g) i
46、n 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 to volume. Calculate the concentration of chloride int
47、he 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 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 Sulf
48、ate 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 a
49、ccordance 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 (9.1.1), in mL,Ca= concentration of sulfate stock (Eq 1), in mg/L,Vb= volume of chloride stock solution (9.1.2)inmL,Cb= concentration o
