1、Designation: D 5827 95 (Reapproved 2002)Standard Test Method forAnalysis of Engine Coolant for Chloride and Other Anionsby Ion Chromatography1This standard is issued under the fixed designation D 5827; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 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 covers the chemical analysis of enginecoolant for chloride ion by hig
3、h-performance ion chromatog-raphy (HPIC). Several other common anions found in enginecoolant can be determined in one chromatographic analysis bythis test method.1.2 This test method is applicable to both new and usedengine coolant.1.3 Coelution of other ions may cause interferences for anyof the li
4、sted anions. In the case of unfamiliar formulations,identification verification should be performed by either orboth fortification and dilution of the sample matrix with theanions of interest.1.4 Analysis can be performed directly by this test methodwithout pretreatment, other than dilution, as requ
5、ired by thelinear ranges of the equipment. Table 1 indicates severalapplicable anions and approximate detection limits.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.6 This standard does not purport to address all of the
6、safety 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 its use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for
7、Reagent Water2D 1176 Test Method for Sampling and Preparing AqueousSolutions of Engine Coolants or Antirusts for TestingPurposes33. Summary of Test Method3.1 A small volume of working sample is prepared bydilution of the sample with the method eluant. This dilutedsample is filtered and pumped throug
8、h two ion exchangecolumns and a suppressor and into a conductivity detector. Ionsare separated based on their affinity for exchange sites of theresin with respect to the resins affinity for the eluant. Thesuppressor increases the sensitivity of the method by bothincreasing the conductivity of the an
9、alytes and decreasing theconductivity of the eluant. The suppressor converts the eluantand the analytes to the corresponding hydrogen form acids.Anions are quantitated by integration of their response com-pared with an external calibration curve and are reported asmilligrams per litre (mg/L).4. Sign
10、ificance and Use4.1 This test method provides for the qualitative and quan-titative determination of common anions in engine coolant inthe milligrams per litre to low percent range and requires onlya few millilitres or microlitres of sample per test, with resultsavailable in less than 30 min. Accept
11、able levels of chloride andother anions vary with manufacturers blending specificationsand applicable ASTM minimum or maximum specifications.5. Interferences5.1 Interferences can be caused by substances with similarretention times, especially if they are in high concentrationcompared to those of the
12、 analyte of interest. Sample dilutionwill be used to minimize or solve most interference problems.5.2 A water dip (solvent system peak) can cause interfer-ence with some integrators. This is eliminated by dilution withthe eluant if the sample dilution factor is 49 + 1 (v/v) or greater.Below this dil
13、ution, it is best to add a spike of eluantconcentrate to the sample such that the sample is not diluted1This test method is under the jurisdiction of ASTM Committee D15 on EngineCoolants and is the direct responsibility of Subcommittee D15.04 on ChemicalProperties.Current edition approved Sept. 10,
14、1995. Published November 1995.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 15.05.TABLE 1 Analytes and Minimum Detection LimitsAnalyte Detection Limit, mg/LAChloride (Cl) 2.0Nitrite (NO2) 5.0Bromide (Br) 4.0Nitrate (NO3) 7.1o-Phosphate (HPO4)220.0Sulfate (SO4)28.0Oxal
15、ate (C2O4)212.0ADetermined using 100-L sample volume. Sample diluted 99 + 1 (v/v) withchromatographic eluant 30-S/cm full scale, suppressed conductivity detection.Dionex AS4ASC column with AG4ASC guard columns. Other systems will requireMDL determinations using chosen dilution factors, eluants, colu
16、mns, and detector.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.significantly and the resulting test solution matches the eluantused in the system. One method is the addition of 100 L of100X eluant concentrate to 10.0 mL of sample
17、or standard.5.3 Method interferences can be caused by the contamina-tion of glassware, eluant, reagents, etc. Great care must betaken to ensure that contamination, especially by chloride, iskept at the lowest possible levels.5.4 Pre-rinsing of the sample preparation containers withdeionized water is
18、 mandatory.5.5 The use of latex gloves is highly recommended toprevent contamination.6. Apparatus6.1 Analytical Balance, capable of weighing accurately to0.0001 g.6.2 Ion ChromatographAnalytical system with all re-quired accessories including syringes, columns, suppressor,gasses, and detector. Colum
19、n life and performance are en-hanced by the use of a two-eluant channel gradient pump, ifavailable.6.3 Guard Column, for protection of the analytical columnfrom strongly retained constituents. Better separations areobtained with additional plates.6.4 Anion Separator Column, capable of producing anal
20、yteseparation equivalent to or better than that shown in Fig. 1.46.5 Anion Suppressor DeviceMicro membrane suppressoror equivalent.5A cation exchange column in the hydrogen formhas been used successfully, but it will periodically need to beregenerated as required, being indicated by a high backgroun
21、dconductivity and low analyte response.6.6 Conductivity Detector, low volume (2 L) and flow,temperature compensated, capable of at least 0 to 1000 S/cmon a linear scale.6.7 Integrator or Chromatography Data System Software,capable of obtaining approximately the same detection limitsas are listed in
22、Table 1.6.8 Drying Oven, controlled at 105, 150, and 600 6 5C.6.9 Desiccator.7. Reagents7.1 Purity of ReagentsReagent grade or higher puritychemicals shall be used for the preparation of all samples,standards, eluants, and regenerator solutions. Unless otherwiseindicated, it is intended that all rea
23、gents conform to thespecifications of the Committee on Analytical Reagents of theAmerican Chemical Society, where such specification areavailable.6Other grades may be used, provided it is firstascertained that the reagent is of sufficiently high purity topermit its use without lessening the accuracy
24、 of the determi-nation.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II of Specification D 1193. It is recommended that allwater be filtered through a 0.2-m filter. For eluant preparation,degas the water by sparging with
25、 helium or vacuum degassingand sonication.7.3 Eluant Buffer Stock SolutionSodium bicarbonate(NaHCO3) 1.5 mM and sodium carbonate (Na2CO3) 1.2 mM.Dissolve 2.5203 6 0.0005 g of NaHCO3and 2.5438 6 0.0005gofNa2CO3in reagent water in a 1000-mL Type A volumetricflask and dilute to 1 L. Dilute 100.0 mL of
26、this stock solutionto 2000 mL in a 2-L Type A volumetric flask with degassedreagent water. The pH of the stock solution is 10.1 to 10.3(based on pKacalculation). The eluant solution used may bedifferent if other system or analytical columns are used.7.4 Stock Bromide SolutionDry approximately2gofsod
27、ium bromide (NaBr) for6hat150C and cool in adesiccator. Weigh and dissolve 1.2877 g of the dried salt inreagent water and dilute to 1 L (1.00 mL = 1.00 mg bromide).7.5 Stock Chloride SolutionDry approximately2gofsodium chloride (NaCl) for1hat600C and cool in adesiccator. Weigh and dissolve 1.6485 g
28、and dilute to 1 L withreagent water (1.00 mL = 1.00 mg Cl).7.6 Stock Formate SolutionDry approximately2gofsodium formate (NaHCO2) at 105C for 6 h and cool in adesiccator. Weigh and dissolve 1.4775 g of the salt in reagentwater and dilute to 1 L (1.00 mL = 1.00 mg formic acid).7.7 Stock Glycolic Acid
29、 SolutionWeigh and dissolve1.0000 g of the solid acid in reagent water and dilute to 1 L(1.00 mL = 1.00 mg glycolate).4Analytical column PN AS4ASC and AG4ASC guard columns manufactured byDionex Corp., 1228 Titan Way, Sunnyvale CA 94088-3603, have been foundsatisfactory for this purpose.5AMMS P.N. 37
30、106 manufactured by Dionex Corp., 1228 Titan Way, SunnyvaleCA 94088-3603, has been found satisfactory for this purpose.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical
31、 Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.FIG. 1 Sample RunChloride Peak at 1.7 minD 5827 95 (2002)27.8 Stock Nitrate SolutionDry approxima
32、tely2gofso-dium nitrate (NaNO3) for 24 h at 105C and cool in adesiccator. Weigh and dissolve 1.3707 g and dilute to 1 L withreagent water (1.00 mL = 1.00 mg NO3).7.9 Stock Nitrite SolutionDry approximately2gofso-dium nitrite (NaNO2) for 24 h in a desiccator containingconcentrated sulfuric acid (rela
33、tive density of 1.84). Weigh anddissolve 1.4998 g and dilute to 1 L with reagent water (1.00mL = 1.00 mg NO2). Refrigerate and prepare weekly becausenitrite is oxidized easily.7.10 Stock Oxalic Acid SolutionWeigh and dissolve1.4002 g of oxalic acid dihydrate (C2H2O42H2O) in reagentwater and dilute t
34、o 1 L (1.00 mL = 1.00 mg oxalic acid).7.11 Stock Phosphate SolutionWeigh and dissolve 1.4330g of potassium dihydrogen phosphate (KH2PO4) and dilute to1 L with reagent water (1.00 mL = 1.00 mg PO43).7.12 Stock Sulfate SolutionDry approximately2gofanhydrous sodium sulfate (Na2SO4)for1hat105C and cooli
35、n a desiccator. Weigh and dissolve 1.4790 g and dilute to 1 Lwith reagent water (1.00 mL = 1.00 mg SO42).7.13 Suppressor Solution for Membrane Suppressor0.025N H2SO4. Carefully add 13.7 mL of reagent sulfuric acid(relative density of 1.84) to approximately 500 mL reagentwater in a 1-L volumetric fla
36、sk. Dilute to 1000 mL with reagentwater. Dilute 100 mL of this concentrate to 2000 mL withreagent water for the final working suppressor solution.7.14 StabilityStandard stock solutions are stable for atleast one month when stored at 4C. Fresh nitrite and phos-phate standards must be prepared weekly.
37、8. Sampling8.1 Collect the sample in a scrupulously clean glass orpolyethylene bottle in accordance with Test Method D 1176.Collect at least 100 mL of sample.9. Calibration and Standardization9.1 Analyze each standard solution separately to determinethe analytes retention time.9.2 Set the chromatogr
38、aph up in accordance with the con-ditions specified in Table 2 and Fig. 2. The use of otherequipment, eluants, or flows requires calculation of suitabledilution factors and instrument settings that permit the analystto obtain the resolution and detection limits given in Fig. 1 andTable 1, respective
39、ly.9.3 Prepare concentrations of chloride at 0.08, 0.4, 0.8, and4.0 mg/L from the stock solution. All final solutions should bemade with eluant as described in 5.2. Calibrate the ionchromatograph with at least five levels of the analyte, startingnear but above the minimum detection limit (MDL) and f
40、urtherdefining the working range in samples subsequent to dilution.These chloride analyte examples reflect a dilution of 99 + 1(v/v) with eluant. If it is desirable to calibrate for another anionspecies, these may be combined in the preceding five calibra-tion standards once the retention times have
41、 been establishedindividually. Concentrations of these other anions in thecalibration solutions must bracket the expected range for thesespecies and include a level near the MDL for each species.NOTE 1Ion chromatography equipment other than that described inthis test method may require that standard
42、s be prepared at higher or lowerlevels.9.4 Analyze a blank containing only the eluant as describedin Section 10.9.5 A mid-range standard must be used to verify theresolution of anions, regardless of a desire to quantitate all ofthem.9.6 Analytical curves must be established at only onedetector scale
43、 setting in order to prevent a change of slopeaffecting the analytical curve.9.7 The analytical calibration curve and an eluant blankshall be verified daily prior to the analysis of samples to verifythe system resolution, calibration, and sensitivity.9.8 The analytical calibration curve, analyte ret
44、ention timesand resolution, and an eluant blank shall be verified subsequentto a change of the system eluant.9.9 Conditions:Column: ion chromatography Flow: 2 mL/minDetector: see 6.6 Suppressor flow: 2 mL/minEluant: see 7.3 Sample loop: 50 LNOTE 2If a gradient pump is available, refer to Fig. 2 for
45、an exampleof a step gradient that has proven successful for cleaning the column ofstrongly retained species such as polyphosphates and molybdate, whichwould otherwise elute in subsequent runs.NOTE 3The sample loop volume will vary based on the columncapacity, sensitivity, and other factors. Refer to
46、 ion chromatographyequipment manuals and column information for machine-specific details.10. Procedure10.1 Set the ion chromatograph up in accordance with themanufacturers instructions.10.2 Equilibrate the system by pumping eluant for 15 to 30min, until a stable baseline is obtained. Sample preparat
47、ion isusually performed by 99 + 1 (v/v) dilution with eluant.10.3 Flush the injection loop with 2 to 3 mL of sample usinga 10-mL disposable plastic syringe fitted with a 0.2-m syringefilter.710.4 Start the chromatographic run in accordance with themanufacturers instructions.10.5 At least one duplica
48、te and one fortified coolant samplemust be analyzed with each batch of ten or fewer samples.Results must be recorded in the laboratory manual. Thefortified sample is to be prepared by addition of a mixedanalyte mid-range standard. Addition of 100 L of fortification7Nalgene Catalogue No. 190-202, or
49、equivalent.TABLE 2 Chromatographic ConditionsAnalyte Peak No. Retention Time, minChloride 2A1.7Nitrite 3 2.1Bromide 4 3.3Nitrate 5 3.7Phosphate 6 7.7Sulfate 7 10.5Oxalate 8 13.3AFluoride, acetate, formate, and glycolate will all elute before chloride, and poorresolution of these species often precludes the quantitation of any, or all four, ofthem.D 5827 95 (2002)3standard solution to 10 mL of prepared sample in eluant willnot dilute the sample appreciably.11. Calculation11.1 Integrate the peak area for determination of the con-centra
