1、Designation: D 7319 07An American National StandardStandard 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 D 7319; the number immediately following
2、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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method cove
3、rs a direct injection ion chromato-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.
4、020 mg/kg of total or potential inor-ganic sulfate and 1.050 mg/kg of inorganic chloride.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, assoc
5、iated 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 for hazards prior to
6、 usage.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 4052 Test Method for Density and Relative Density ofLiquids by Digital Density MeterD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andP
7、etroleum ProductsD 5827 Test Method for Analysis of Engine Coolant forChloride and Other Anions by Ion ChromatographyD 6299 Practice for Applying Statistical Quality AssuranceTechniques to Evaluate Analytical Measurement SystemPerformanceD 6792 Guide for Quality System in Petroleum Productsand Lubri
8、cants Testing LaboratoriesD 7318 Test Method for Total Inorganic Sulfate in Ethanolby Potentiometric TitrationD 7328 Test Method for Determination of Total and Poten-tial Inorganic Sulfate and Total Inorganic Chloride in FuelEthanol by Ion Chromatography Using Aqueous SampleInjection3. Terminology3.
9、1 Definitions of Terms Specific to This Standard:3.1.1 inorganic chloride, nchloride present as hydrochlo-ric acid, ionic salts of this acid, 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
10、 sulfate, ntotal sulfur species present in thesample that will oxidize to sulfates in the presence of anoxidizing agent.3.1.4 total sulfate, ninorganic sulfate species actuallypresent in the sample at the time of analysis with no oxidationtreatment.4. Summary of Test Method4.1 For total sulfate and
11、chloride, a small volume of anethanol sample is directly injected into a suitably configuredion chromatograph in accordance with manufacturers recom-mendations 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 inje
12、cted 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. Thesuppressor increases the sensitivity of the test method by both1This test method is under the jurisdiction of ASTM Committee D02 onPetroleu
13、m Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved Feb. 1, 2007. Published March 2007.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
14、 of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.increasing the conductivity of the analytes and decreasing theconductivity of the e
15、luent. It also converts the eluent andanalytes to the corresponding hydrogen forms of anions.Anions are quantified by integration of their responses com-pared with an external calibration curve, and are measured asmilligrams/litre, then converted to milligrams/kilograms. Thecalibration standards are
16、 prepared in an aqueous matrix.4.2 Similar methods for chloride and sulfate determinationscan be found in Test Method D 5827 for engine coolant, andfor ethanol in Test Method D 7328 by ion chromatography withaqueous sample injection, and for sulfate only in Test MethodD 7318 by potentiometric lead t
17、itration.5. Significance and Use5.1 Sulfates and 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 Total and potential sulfate and total chloride content,
18、 asmeasured by this test method, can be used as one measure ofthe acceptability of gasoline components for automotive spark-ignition engine fuel use.6. Interferences6.1 Interferences can be caused by substances with similarion chromatographic retention times, especially if they are inhigh concentrat
19、ion compared to the analyte of interest. 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 b
20、e 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 method, interferences can be caused bycontamination of glassware, eluent, reagents, and the like.Great care must be taken to ensure that contam
21、ination is keptat the lowest possible levels. The use of powder-free gloves ishighly recommended to prevent sample contamination.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 chlor
22、ide.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 automatic pipets fitted with disposable polypropylenetip
23、s.7.5 Volumetric Flasks (with Glass Stoppers), Class A of 10,25, 50, 100, 1000, 2000cc capacity.7.5.1 Container, equipped with a closure to prevent ethanolevaporation, 1 L (for sample collection).7.6 Ion Chromatograph, analytical system with all requiredaccessories including syringes, columns, suppr
24、essor, 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 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 recomm
25、ended for this determination by the manu-facturer.FIG. 1 Typical Ion Chromatogram of a Solution Containing 1 mg/L of Various Anions in WaterD73190727.6.3 Guard Column, for protection of the analytical columnfrom strongly retained constituents. Better separations areobtained with additional theoretic
26、al 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, Two different approaches(tri-chamber and continuous) were used in the precision study,others may be used as long as t
27、hey produce comparable results.Follow the ion chromatography instrument vendors recom-mendations.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 re
28、generated 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.7.6.7 Integrator or Chromatog
29、raphy 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 shall be used for the preparatio
30、n 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.3Other grades may be used, provided
31、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 in Specification D 1193. For el
32、uent preparation andhandling, comply with all ion chromatograph instrument andcolumn 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
33、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 oranalytical columns are used.NOTE 1Other volum
34、es 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 Solution for Suppressor0.1 Msulfuric acid
35、. 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 concentrated acid.) Dilute to 1000mL with r
36、eagent 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 reagents. Follow the specific guidelines for
37、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 methanol, formula 3A or his-tological
38、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 Hydrogen Peroxide Solution, 30 %commerci
39、allyavailable 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, and store in adesiccator. Accurately w
40、eigh 2.96 g anhydrous sodium sulfateto the nearest tenth of a milligram and transfer to a 1Lvolumetric flask. Add Type II water to dissolve the sodiumsulfate, and make to volume. Calculate the concentration ofsulfate in the solution in accordance with Eq 1. Other volumesof stock solution can be prep
41、ared using the appropriate ratio ofreagents.Stock Sulfate mg/L!5gNa2SO4!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 2000 mg/L)To ensure dryness, place sodium chloride (5 g)
42、 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 Type II water to dissolve the sodiumchloride and make to volume. Calculate the concentration of3Re
43、agent Chemicals, American Chemical Society Specifications. AmericanChemical Society, Washington, D.C. For suggestions on testing of reagents not listedby the American Chemical Society, see Annual Standards for Laboratory Chemi-cals, BDH Ltd., Dorset, U.K., and the United States Pharmacopeia and Nati
44、onalFormulatory, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D7319073chloride in the solution in accordance with Eq 2. Othervolumes of stock solution can be prepared using the appropri-ate ratio of reagents.Stock Chloride mg/L!5g NaCl!0.6068!1000 mg/g!/1 L (2)where:g NaCl = weight in g
45、rams of NaCl dissolved in 1 L, and0.6068 = weight percent chloride in NaCl.9.2 Chloride and Sulfate Standards in WaterType II 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 sto
46、ck solutions from 9.1 areadded quantitatively into the flask and mixed quantitativelywith Type II water in accordance with Table 1. Be very carefulto measure the exact volumes of the sulfate and chloride stocksolutions that are added to the flask, and fill the flask to 1.00 Lwith Type II water. The
47、sulfate and chloride concentrations ofeach standard 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 o
48、f chloride stock solution (9.1.2)inmL,Cb= concentration of chloride stock (Eq 2), in mg/L,V = final volume of standard solution, in L.9.2.2 Multiples or fractions of Table 1 values can be used toprepare different volumes of standards, but Eq 3 and Eq 4 arestill used to calculate standard ion concent
49、rations.NOTE 3Alternatively, commercially available stock calibration solu-tions can be used, provided that the solutions are traceable to primarystock solutions or certified reference materials and are free from otheranalytes.10. Calibration10.1 Set up the ion chromatograph in accordance with themanufacturers instructions. No specific parameters are givenhere since different equipment will require differing eluent,flow conditions, and instrument settings. Calibrate the ionchromatograph with at least five levels of sulfate and chloride,st
