1、Designation: E 2469 08aStandard Test Method forChloride in Mono-, Di- and Tri-ethylene Glycol by IonChromatography1This standard is issued under the fixed designation E 2469; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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 the determination of inorganicchloride (chloride ion) in monoethylene glycol (MEG), dieth
3、-ylene glycol (DEG) and triethylene glycol (TEG) in the rangeof 0.01 to 1.0 mg/kg by ion chromatography (IC).1.2 Ethylene glycol can be analyzed directly by this testmethod without any sample preparation or diluted with highquality deionized water if an autosampler is used and dilutionis necessary (
4、that is, 50:50 or other suitable ratio).1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3.1 The exception is the additional information of (psi) in9.3.3.1.4 Review the current Material Safety Data Sheets (MSDS)for detailed
5、 information concerning toxicity, first-aid proce-dures and safety precautions.1.5 This standard does not purport to address all of thesafety 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 to d
6、etermine theapplicability of regulatory limitations prior to use. For specifichazard statements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-c
7、ialty ChemicalsE 300 Practice for Sampling Industrial Chemicals3. Summary of Test Method3.1 An aliquot of the glycol sample is injected directly(manually) or diluted (via autosampler) into an ion chromato-graph consisting of an injector with a fixed sample loop, twoanion exchange columns (guard and
8、separator column), ananion suppressor and a conductivity detector. Ions are sepa-rated based on their affinity for the ion exchange sites of theresin with respect to the resins affinity for the eluent. Thesuppressor increases the sensitivity of the test method by bothincreasing the conductivity of t
9、he analytes and decreasing theconductivity of the eluent. The suppressor converts the eluentand the analytes to the corresponding hydrogen form acids.The chloride is detected by conductivity detection and identi-fied by retention time. Quantitation is by peak area using anexternal standard calibrati
10、on curve. Instructions are providedfor two equivalent IC systems.4. Significance and Use4.1 This test method provides for the quantitative determi-nation of inorganic chloride (chloride ion) in monoethyleneglycol (MEG), diethylene glycol (DEG) and triethylene glycol(TEG) using ion chromatography wit
11、h conductivity detection.The analysis time is less than 5 min with little or no samplepreparation required. Conductivity detection is a universaldetection mode and is linear over the range of the method.Acceptable levels of chloride in polyester-grade and low-conductivity-grade MEG vary with the man
12、ufacturers speci-fications but are normally in the low mg/kg range. Knowledgeof the chloride content in polyester-grade and low-conductivity-grade MEG is required to establish whether theMEG product meets specification requirements.4.2 Glycols have high viscosities and a dilution with highquality de
13、ionized water may be required depending on thecapability of the autosampler, if used, to deliver the injection.All standards and samples, whether diluted or not should betreated in the same manner.5. Interferences5.1 The identification of chloride is based on retention time.Interferences can be caus
14、ed by ionic substances with retentiontimes similar to that of chloride. If the eluent conditions arechanged or the column capacity changes, it is possible thatother anions may coelute with chloride and cause an interfer-ence.1This test method is under the jurisdiction of ASTM Committee E15 onIndustr
15、ial and Specialty Chemicals and is the direct responsibility of SubcommitteeE15.02 on Product Standards.Current edition approved Dec. 15, 2008. Published January 2009. Originallyapproved in 2006. Last previous edition approved in 2008 as E 2469 08.2For referenced ASTM standards, visit the ASTM websi
16、te, 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor
17、Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Any anion that elutes after chloride under the analysisconditions used in the test method may cause an interference ifthe run time of the method isnt long enough to include thatanion. When the run time of a method is too short,
18、a late elutinganion from one analysis may be detected during the nextanalysis and cause an interference if it elutes at the same timeas chloride. Carbonate, if present in a sample, may cause aninterference in IC systems using hydroxide eluent (like Con-figuration B) if the run time of the analysis i
19、s not long enoughto include the carbonate peak. The elution time of carbonateunder the analysis conditions used in this test method isdirectly related to the amount of carbonate in the sample. Thehigher the concentration of carbonate in a sample, the faster thecarbonate elutes from the column.5.3 Me
20、thod interferences can be caused by the contamina-tion of glassware, eluent and reagents with chloride. Care mustbe taken to ensure glassware and apparatus are free of chloride.The use of latex gloves is recommended to prevent chloridecontamination while handling samples and reagents.5.4 In an IC sy
21、stem with an electrolytic membrane basedsuppressor operated in the recycle mode, the eluent is recycledback through the suppressor after it exits the conductivity cellto provide a source of water for electrolytic generation ofhydronium ions for the regenerant. Using this system configu-ration, there
22、 is an interference caused by the glycol sample asit passes back through the suppressor. This interference appearsas a large broad peak that upsets the baseline during the timechloride elutes from the column. Accurate quantitation ofchloride is very difficult if not impossible with this interference
23、present. To avoid this interference, an external supply ofreagent water is used as the source of hydronium ions for theregenerant. In the external water mode, water flows counter-current to the eluent through the suppressor. The water can bepressurized or pumped through the suppressor to achieve the
24、required flow rate.5.5 No other direct interferences have been observed in theuse of this test method. If results are suspect based on theanalytical history of the product, the data should be confirmedby an alternate test method.6. Apparatus6.1 Analytical Balance, capable of weighing 200 g to thenea
25、rest 0.0001 g. (See Note 1.)6.2 Pipettes, capable of measuring from 100-L to 10-mL.(See Note 1.)NOTE 1The accuracy of balances and pipettes should be confirmed ona regular basis and documentation of the check should be kept.6.3 Ion Chromatograph, Configuration A (Bottled EluentSystem - Carbonate-Bas
26、ed) (see Note 2)Analytical instru-ment with all the required accessories including an eluentpump, temperature-controlled low volume ( 2 L) conductiv-ity cell, conductivity detector, PEEK tubing, and a PEEKinjection valve with a fixed sample loop. An auxiliary regen-erant pump or pressurized 4-L reag
27、ent bottle is required forexternal regenerant delivery. The instrument must be suitablefor analysis according to the operating conditions given in11.1. Autosampler optional.NOTE 2The ion chromatography (Configuration A) uses a carbonatebased eluent system in which the eluent is prepared by the analy
28、st fromanalytical grade reagents or commercially available concentrated carbon-ate solutions. There is more variability in the retention time of chloridewith this type of system as a result of variations in the concentration of theeluent prepared by analysts. This is the oldest and most commonly use
29、d ICsystem.6.3.1 Anion Exchange Guard Column (for Carbonate-BasedEluent), for protection of the analytical column from stronglyretained components and organics. Better separations areobtained with the additional plates of the guard column.6.3.2 Anion Exchange Separator Column (for Carbonate-Based El
30、uent), capable of producing separation of the chlorideequivalent to or better than that shown in Fig. 1.FIG. 1 Representative Sample Chromatogram Obtained Using the Conditions Outlined in 11.1 (Configuration A)E 2469 08a26.3.3 Anion Suppressor, an electrolytic self-regeneratingmembrane suppressor, m
31、icromembrane suppressor or equiva-lent suppressor capable of lowering the background conduc-tance of the eluant to a level that allows the method detectionlimit to be achieved.6.3.4 Chromatography Data System, for data acquisitionand data processing.6.4 Ion Chromatograph, Configuration B (Eluent Gen
32、era-tion System - Hydroxide Eluent) (see Note 3)Analyticalinstrument with all the required accessories including an eluentpump, temperature controlled low volume ( 2 L) conductiv-ity cell, conductivity detector, PEEK tubing, PEEK injectionvalve with a fixed sample loop and electrolytic eluent genera
33、-tion module. An auxiliary regenerant pump or pressurized 4-Lreagent bottle is required for external regenerant delivery. Theinstrument must be suitable for analysis according to theoperating conditions given in 11.2.NOTE 3The IC system (Configuration B) uses on-line electrolyticeluent generation to
34、 produce a hydroxide eluent. The hydroxide eluent isgenerated from reagent water using an eluent generator cartridge. Theconcentration of hydroxide eluent is very reproducible, so the retentiontime for chloride is less variable than with a carbonate eluent. This newertechnology for eluent generation
35、 eliminates the variability of eluentpreparation by an analyst. It also eliminates the problems with eluentaging (weakening) and contamination.NOTE 4The IC system in Configuration B uses on-line electrolyticeluent generation to produce the eluent. The type of eluent produceddepends on the eluent gen
36、erator cartridge used with the IC system. Thereare four types of eluent generator cartridges including potassium hydrox-ide, carbonate-bicarbonate, lithium hydroxide and sodium hydroxide. Forthis test method the potassium hydroxide eluent cartridge is recommendedfor use with hydroxide selective colu
37、mns. The carbonate-bicarbonateeluent cartridge and eluent pH modifier can be used with carbonateselective columns (6.3.1 and 6.3.2) if the analyst prefers on-linecarbonate-bicarbonate eluent generation.6.4.1 Anion Exchange Guard Column (for Hydroxide Elu-ent), for protection of the analytical column
38、 from stronglyretained components and organics. Better separations areobtained with the additional plates of the guard column.6.4.2 Anion Exchange Separator Column (for HydroxideEluent), capable of producing separation of chloride equivalentto or better than that shown in Fig. 2.6.4.3 Anion Exchange
39、 Trap Column (for Hydroxide Eluent),electrolytic continuously regenerated trap column or equivalenttrap column capable of removing anionic impurities fromreagent water used with the eluent generation cartridge.FIG. 2 Representative Sample Chromatogram Obtained Using the Conditions Outlined in 11.2 (
40、Configuration B)E 2469 08a36.4.4 Anion Suppressor, an electrolytic self-regeneratingmembrane suppressor, micromembrane suppressor or equiva-lent suppressor capable of lowering the background conduc-tance of the eluant to a level that allows the method detectionlimit to be achieved.6.4.5 Eluent Gener
41、ator Cartridge, capable of producingcarbonate-free potassium hydroxide.36.4.6 Chromatography Data System, for data acquisitionand data processing.6.4.7 Chromatography Operating System, capable of con-trolling the current required for eluent generation and trapcolumn regeneration.6.5 Volumetric Glass
42、ware, 100-mL, 1-L, and 2-Lvolumetricflask. (See Note 5.)6.6 Plastic Cups with Lids, 120 mL. (See Note 5.)6.7 Weigh Dish, small disposable polystyrene. (See Note 5.)6.8 Bottles with Caps, 125-mL Nalgene low density poly-ethylene (LDPE) narrow mouth. (See Note 5.)6.9 Plastic Syringe, 10-mL with Luer-L
43、ok Tip. (See Note5.)NOTE 5Care should be taken to ensure glassware, reagents andapparatus are free of chloride contamination.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the sp
44、ecifications of the Committee onAnalytical Reagents of the American Chemical Society (ACS)where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determina
45、tion.7.2 High-Purity WaterUnless otherwise indicated, refer-ences to water shall be understood to mean reagent water asdefined by Type II of Specification D 1193. It is recommendedthat all water be filtered through a 0.2-m filter. For eluentpreparation, it is recommended to degas the water by spargi
46、ngwith helium or vacuum degassing and sonication.7.3 Sodium Chloride, ACS reagent grade.7.4 Chloride Quality Assurance Check Standard, an inde-pendent, certified 10 g/mL chloride standard (not made fromsodium chloride in 7.3), may be purchased commercially.7.5 Sodium Carbonate (Configuration A), ACS
47、 reagentgrade.7.6 Sodium Bicarbonate (Configuration A), ACS reagentgrade.7.7 Sodium Carbonate Concentrate (Configuration A), 0.5M sodium carbonate, commercially available.7.8 Sodium Bicarbonate Concentrate (Configuration A), 0.5M sodium bicarbonate, commercially available.7.9 Monoethylene Glycol (ME
48、G) (High Purity), with lowconcentrations of impurities.7.10 Diethylene Glycol (DEG) (High Purity), with lowconcentrations of impurities.7.11 Triethylene Glycol (TEG) (High Purity), with lowconcentrations of impurities.NOTE 6 Impurities in high-purity MEG, DEG or TEG used forpreparation of the chlori
49、de working standards or for sample dilutionshould not exceed 0.01 mg/kg. This information should be provided by thesupplier or determined by the analyst before use.7.12 Sulfuric Acid (for use with anion micromembranesuppressor), concentrated sulfuric acid (95 to 98 %).7.13 Anion Regenerant Concentrate (for use with anionmicromembrane suppressor), 1 M sulfuric acid, commerciallyavailable.7.14 Isopropyl Alcohol (2-Propanol), ACS reagent grade.7.15 Methyl Alcohol (Methanol, alternate for IsopropylAlcohol), ACS reagent grade.7.16 Monoethylene Glycol Quality Control S
