1、Designation: E 2469 06Standard Test Method forChloride in Monoethylene Glycol by Ion Chromatography1This 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 of last revisi
2、on. 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 determination of inorganicchloride (chloride ion) in polyester-grade and low-conductivity-grade mono
3、ethylene glycol (MEG) in the range of0.01 to 1.0 mg/kg by ion chromatography (IC).1.2 Monoethylene glycol can be analyzed directly by thistest method without any sample preparation.1.3 The values given in SI units are to be considered as thestandard. The values given in parentheses are for informati
4、ononly.1.4 Review the current Material Safety Data Sheets (MSDS)for detailed 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
5、this standard to establish appro-priate safety and health practices and to determine 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 t
6、he Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty ChemicalsE 300 Practice for Sampling Industrial Chemicals3. Summary of Test Method3.1 An aliquot of the polyester-grade or low-conductivity-grade monoethylene glycol (MEG) sample is injected directly(manually) into an
7、ion chromatograph consisting of an injectorwith a fixed sample loop, two anion exchange columns (guardand separator column), an anion suppressor and a conductivitydetector. Ions are separated based on their affinity for the ionexchange sites of the resin with respect to the resins affinity forthe el
8、uent. The suppressor increases the sensitivity of the testmethod by both increasing the conductivity of the analytes anddecreasing the conductivity of the eluent. The suppressorconverts the eluent and the analytes to the correspondinghydrogen form acids. The chloride is detected by conductivitydetec
9、tion and identified by retention time. Quantitation is bypeak area using an external standard calibration curve. Instruc-tions are provided for two equivalent IC systems.4. Significance and Use4.1 This test method provides for the quantitative determi-nation of inorganic chloride (chloride ion) in m
10、onoethyleneglycol (MEG) by direct injection using ion chromatographywith conductivity detection. The analysis time is less than 5min with no sample preparation required. Conductivity detec-tion is a universal detection mode and is linear over the rangeof the method. Acceptable levels of chloride in
11、polyester-gradeand low-conductivity-grade MEG vary with the manufacturersspecifications but are normally in the low mg/kg range.Knowledge of the chloride content in polyester-grade andlow-conductivity-grade MEG is required to establish whetherthe product meets specification requirements.5. Interfere
12、nces5.1 The identification of chloride is based on retention time.Interferences can be caused 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 a
13、n interfer-ence.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, a late elutinganion from one analysis may be detecte
14、d 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 is not long enoughto include the carbonate peak. The
15、elution time of carbonateunder the analysis conditions used in this test method isdirectly related to the amount of carbonate in the sample. The1This test method is under the jurisdiction of ASTM Committee E15 onIndustrial and Specialty Chemicals and is the direct responsibility of SubcommitteeE15.0
16、2 on Product Standards.Current edition approved May 1, 2006. Published May 2006.2For 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 to the standards Document Summary page
17、onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.higher the concentration of carbonate in a sample, the faster thecarbonate elutes from the column.5.3 Method interferences can be caused by the contamina-tion of glas
18、sware, 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 system with an electrolytic membrane basedsuppressor operated in
19、 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 is an interference caused by the glycol sample asit passes ba
20、ck 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 interferencepresent. To avoid this interference, an external supply ofreag
21、ent 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 therequired flow rate.5.5 No other direct interferences have been
22、 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 thenearest 0.0001 g. (See Note 1.)6.2 Pipettes, capable of measuring
23、 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-Based) (see Note 2)Analytical instru-ment with all the required a
24、ccessories 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 reagent bottle is required forexternal regenerant delivery. The in
25、strument must be suitablefor analysis according to the operating conditions given in11.1.NOTE 2The ion chromatography (Configuration A) uses a carbonatebased eluent system in which the eluent is prepared by the analyst fromanalytical grade reagents or commercially available concentrated carbon-ate s
26、olutions. 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 used ICsystem.6.3.1 Anion Exchange Guard Column (for Carbonate-BasedEluent), for protec
27、tion 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 Eluent), capable of producing separation of the chlorideequivalent to or better than t
28、hat shown in Fig. 1.6.3.3 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.6.3.4 Chromatography Data
29、 System, for data acquisitionand data processing.6.4 Ion Chromatograph, Configuration B (Eluent Genera-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
30、 detector, PEEK tubing, PEEK injectionvalve with a fixed sample loop and electrolytic eluent genera-tion module. An auxiliary regenerant pump or pressurized 4-Lreagent bottle is required for external regenerant delivery. TheFIG. 1 Representative Sample Chromatogram Obtained Using the Conditions Outl
31、ined in 11.1 (Configuration A)E2469062instrument 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 produce a hydroxide eluent. The hydroxide eluent isgenerated from reagent water using
32、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 eliminates the variability of eluentpreparation by an analyst. It also eliminates the
33、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 generator cartridge used with the IC system. Thereare four types of eluent generator cartr
34、idges 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 columns. The carbonate-bicarbonateeluent cartridge and eluent pH modifier can be used with
35、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 from stronglyretained components and organics. Better separations areobtained with the
36、 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 Trap Column (for Hydroxide Eluent),electrolytic continuously regenerated trap column o
37、r equivalenttrap column capable of removing anionic impurities fromreagent water used with the eluent generation cartridge.6.4.4 Anion Suppressor, an electrolytic self-regeneratingmembrane suppressor, micromembrane suppressor or equiva-lent suppressor capable of lowering the background conduc-tance
38、of the eluant to a level that allows the method detectionlimit to be achieved.6.4.5 Eluent Generator 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-trol
39、ling the current required for eluent generation and trapcolumn regeneration.6.5 Volumetric Glassware, 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 lo
40、w density poly-ethylene (LDPE) narrow mouth. (See Note 5.)3The sole source of supply of the potassium hydroxide eluent generationcartridge known to the committee at this time is Dionex Corp., 1228 Titan Way,Sunnyvale CA94088-3603. If you are aware of alternative suppliers, please providethis informa
41、tion to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.FIG. 2 Representative Sample Chromatogram Obtained Using the Conditions Outlined in 11.2 (Configuration B)E24690636.9 Plastic Syringe, 10-
42、mL with Luer-Lok 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 con
43、form to the specifications 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
44、 the determination.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 w
45、ater by spargingwith 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 (Configu
46、ration A), ACS 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 Monoethyl
47、ene Glycol (MEG) (High Purity), with lowconcentrations of impurities.NOTE 6 Impurities in high-purity MEG used for preparation of thechloride working standards or for sample dilution should not exceed 0.01mg/kg. This information should be provided by the supplier or determinedby the analyst before u
48、se.7.10 Sulfuric Acid (for use with anion micromembranesuppressor), concentrated sulfuric acid (95 to 98 %).7.11 Anion Regenerant Concentrate (for use with anionmicromembrane suppressor), 1 M sulfuric acid, commerciallyavailable.7.12 Isopropyl Alcohol (2-Propanol), ACS reagent grade.7.13 Methyl Alco
49、hol (Methanol, alternate for IsopropylAlcohol), ACS reagent grade.7.14 Monoethylene Glycol Quality Control Sample, polyes-ter grade MEG.8. Reagent Solutions8.1 Chloride Stock Solution (1000 mg/kg Chloride in Wa-ter):NOTE 7As an alternative, a 1000 g/mL chloride standard may bepurchased commercially.NOTE 8The density of the commercial chloride stock solution isassumed to be 1.0 g/mL at room temperature for wt/wt calculations inmg/kg.8.1.1 Place a 125-mL Nalgene LDPE narrow mouth bottleon the balance and tare.8.1.2 Weigh (and record to the nearest 0.0001 g) 0.1649 60
