1、Designation: E2193 08E2193 16Standard Test Method forUltraviolet Transmittance of Monoethylene Glycol(Ultraviolet Spectrophotometric Method)(using UltravioletSpectrophotometry)1This standard is issued under the fixed designation E2193; 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 procedure for the determin
3、ation of the transmittance of monoethylene glycol (1,2-ethanediol;MEG) at wavelengths in the region 220 to 350 nm. The results provide a measure of the purity of the sample with respect toultraviolet absorbing compounds.1.2 The values stated in SI units are to be regarded as standard. No other units
4、 of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regula
5、torylimitations prior to use. For specific hazard statements, see Section 7.1.4 Review the current Material Safety Data Sheets (MSDS)(SDS) for detailed information concerning toxicity, first aidprocedures, and safety precautions.precautions for all materials used in this test method.2. Referenced Do
6、cuments2.1 ASTM Standards:2D1193 Specification for Reagent WaterD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceE131 Terminology Relating to Molecular SpectroscopyE169 Practices for General Techniques of
7、Ultraviolet-Visible Quantitative AnalysisE180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals(Withdrawn 2009)3E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers2.2 Other Document:M
8、anufacturers Instruction Manual of Spectrophotometer3. Summary of Test Method3.1 The product is sampled in such a way as to avoid extraneous contamination and air contact. The absorbance of the samplecontained in a 50-mm or 10-mm cell is measured against water at a series of wavelengths and the tran
9、smittance over a pathlengthof 10 mm is calculated.3.2 This test method can be performed with two options as to sample preparation prior to UV measurement.3.2.1 Option A: Nitrogen sparging of the sample (see 4.2).3.2.2 Option B: No nitrogen sparging.4. Significance and Use4.1 Knowledge of the ultravi
10、olet transmittance of monoethylene glycol is required to establish whether the product meets therequirements of its quality specifications.1 This test method is under the jurisdiction of ASTM Committee E15 on Industrial and Specialty Chemicals and is the direct responsibility of Subcommittee E15.02
11、onProduct Standards.Current edition approved April 1, 2008Jan. 1, 2016. Published May 2008January 2016. Originally approved in 2002. Last previous edition approved in 20042008 asE2193 04.E2193 08. DOI: 10.1520/E2193-08.10.1520/E2193-16.2 For referencedASTM standards, visit theASTM website, www.astm.
12、org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard a
13、nd is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only
14、 the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Dissolved oxygen i
15、n organic solvents, such as MEG, forms complexes that shift the solvent absorption from the vacuumultraviolet range into the measurable UV range (near 190 to 250 nm). Monoethylene glycol has a UV absorption peak at 180 nm.For MEG-oxygen complexes, this peak is shifted to a longer wavelength, thus in
16、creasing the absorbability at 220 nm.4.2.1 However, this effect is not observed in water. There is no significant measurable effect due to dissolved oxygen in waterthat would require nitrogen sparging prior to using for collection of the reference spectrum.4.2.2 Nitrogen sparging and re-measurement
17、of suspect or borderline glycol samples at 220 nm can be used as a tool to ruleout or confirm the presence of UV affecting contaminants other than oxygen.5. Apparatus5.1 Ultraviolet Spectrophotometer, double beam, suitable for measurement at wavelengths in the region 200 to 400 nm, havinga spectral
18、bandwidth of 2.0 nm or less at 220 nm, wavelength accuracy 60.5 nm or less at 220 nm, wavelength repeatability 0.3nm or less at 220 nm and a photometric accuracy of 60.5 % T or less, in the transmittance region above 50 % T. Stray light shallbe less than 0.1 % at 220 nm.The instrument shall be provi
19、ded with matched fused silica quartz (fused silica) cells with pathlengthsof 50 6 0.1 mm or 10 mm 6 0.01 mm. Use of 50-mm cell should provide better precision.5.1.1 Optional Single Beam SpectrophotomerSpectrophotometerUse the same cell for measurement of the blank and thesample.5.2 Nitrogen Strippin
20、g Apparatus (Option A, 3.2.1), consisting of an oil-free pressure reducing valve to fit the nitrogen cylinder,a control valve, vinyl tubing and a disposable glass pipette to be inserted in a 25-mL volumetric flask. flask or bottle. Componentsshould be clean and free of ultraviolet contaminants.Avoid
21、 contacting the sample with any plastic material containing plasticizers.Plasticizers can leach out of the material and cause erroneous results. Replace the disposable pipette by a clean, new one after eachsample handling. (See Section 910.)5.3 Bottles, capacity at least 0.5L, 0.5 L, with lined, wel
22、l-fitting cap. Use a fresh bottle for each determination.5.4 Glassware:5.4.1 Volumetric Flask, Flask or Bottle, 25-mL.25 mL.6. Reagents and Materials6.1 Purity of ReagentsUnless otherwise indicated, it is intended that all reagents shall conform to the specifications of theCommittee on Analytical Re
23、agents of the American Chemical Society where such specifications are available.4 Other grades maybe used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracyof the determination.6.2 Holmium Oxide Wavelength Calibration Fi
24、lter, calibrated (if required; see 8.1.19.1.1).NOTE 1The standard reference material SRM 2034, available from the National Institute of Standards and Technology (NIST),5 is suitable.6.3 Standard Absorbance Filter, with certified absorbance values (if required; see 8.1.29.1.2).NOTE 2The standard refe
25、rence material SRM 2031, available from NIST,5 is suitable. In addition, SRM 935a may be used (see 6.4).6.4 Stray Light Filter, for measuring stray light at 220 nm (if required; see 8.1.39.1.3).NOTE 3The (potassium iodide) standard reference material SRM 2032, available from NIST,5 is suitable (see
26、also 6.8).6.5 Naphthalene Solution(1 mg/L isooctane) Dissolve 1 mg naphthalene in 1000 mL of spectroscopic grade isooctane.(WarningIsooctane is highly flammable and irritating to the respiratory system. Avoid contact with skin. Naphthalene isirritating to the skin, eyes, and respiratory system. It m
27、ay cause sensitization by skin contact. Avoid contact with eyes. Wearsuitable protective clothing.Warning)Isooctane is highly flammable and irritating to the respiratory system. Avoid contact withskin. Naphthalene is irritating to the skin, eyes, and respiratory system. It may cause sensitization by
28、 skin contact. Avoid contactwith eyes. Wear suitable protective clothing.6.6 Nitrogen, minimum purity 99.99 % (V/V), oil-free.6.7 Potassium Dichromate or Potassium Chromate, for checking photometric accuracy (if required; see 8.1.29.1.2).NOTE 4The standard reference material, no. SRM 935a, available
29、 from NIST,5 is suitable.(WarningPotassium dichromate is harmful in contact with skin, toxic if swallowed, and very toxic by inhalation. It is irritatingto the respiratory system and skin. Risk of serious damage to eyes. It may cause sensitization by skin contact. It may cause heritablegenetic damag
30、e. It may cause cancer by inhalation. In case of accident or if you feel unwell, seek medical advice immediately(show the label where possible). Avoid exposureobtain special instructions before use. This material or its container, or both,4 Reagent Chemicals, American Chemical Society Specifications
31、, , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention,
32、 Inc. (USPC),(USP), Rockville, MD.5 Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.E2193 162must be disposed of as hazardous waste. Avoid release to the environment. Refer to special instructions/safety
33、 datasheets.Warning)Potassium dichromate is harmful in contact with skin, toxic if swallowed, and very toxic by inhalation. It isirritating to the respiratory system and skin. Risk of serious damage to eyes. It may cause sensitization by skin contact. It may causeheritable genetic damage. It may cau
34、se cancer by inhalation. In case of accident or if you feel unwell, seek medical adviceimmediately (show the label where possible). Avoid exposureobtain special instructions before use. This material or itscontainer, or both, must be disposed of as hazardous waste. Avoid release to the environment.
35、Refer to special instructions/safetydata sheets.) (WarningPotassium chromate is irritating to eyes, respiratory system, and skin. It may cause sensitization by skincontact. It may cause heritable genetic damage. It may cause cancer by inhalation. In case of accident or if you feel unwell, seekmedica
36、l advice immediately (show the label where possible).Avoid exposureobtain special instructions before use.This materialor its container, or both, must be disposed of as hazardous waste. Avoid release to the environment. Refer to specialinstructions/safety data sheets.Warning)Potassium chromate is ir
37、ritating to eyes, respiratory system, and skin. It may causesensitization by skin contact. It may cause heritable genetic damage. It may cause cancer by inhalation. In case of accident or ifyou feel unwell, seek medical advice immediately (show the label where possible). Avoid exposureobtain special
38、 instructionsbefore use. This material or its container, or both, must be disposed of as hazardous waste.Avoid release to the environment. Referto special instructions/safety data sheets.)6.8 Potassium or Sodium Iodide Solution, for measuring stray light at 220 nm (if required; see 8.1.39.1.3).NOTE
39、5The “UV-VIS Standard” sodium iodide solution,6 is suitable. Potassium iodide solutions can be prepared from NIST standard referencematerial SRM 2032 (see 6.4 and Note 3).6.9 Water, Low UV AbsorbanceHPLC grade.grade or reagent water type I (Specification D1193).6.10 Monoethylene Glycol Quality Contr
40、ol Sample, Sample(only required if maintaining It is recommended to select aMonoethylene Glycolcontrol chart, see sample similar to the product being analyzed and to use it as a quality control sample(Warningsee 7.2). 10.5). Store at a temperature between 0 and 5C. Warm to ambient temperature before
41、 use.To this end, ensureto obtain a sufficient amount and store it in such a way that it is stable for a known period of time and use it as such during thisperiod of time only. For more details, see 11.5.7. Hazards7.1 Consult current OSHA regulations and suppliers Safety Data Sheets and local regula
42、tions for all materials used in this testmethod.7.2 Monoethylene GlycolAlthough monoethylene glycol, in general, is not classified as dangerous or flammable and is notexpected to impose a health hazard when used under normal conditions, it is recommended to avoid inhalation and contact withskin and
43、eyes. Wear suitable protective clothing and gloves. Do not breathe gas, fumes, vapor, or spray. Use only in well-ventilatedareas. In cases of contact with eyes, rinse with plenty of water and seek medical advice.8. Sampling8.1 The following precautions must be observed carefully since the ultraviole
44、t transmittance is very sensitive to small amountsof extraneous material contaminating the sample and to oxygen dissolved in the sample through air contact. The sample connectionmust be protected against accidental contamination and designed so that it will permit convenient positioning of the sampl
45、e bottleto the sample outlet in order to minimize air contact, that is, the descending stream of sample should be as short as possible. Purgethe sampling line thoroughly with sample. Fill the bottle partly with sample, sample (Warningsee 7.2), shake and discard.Repeat the rinsing procedure.Then take
46、 the sample in a “gentle stream,” thus filling the bottle to within 10 mm of the top.A“gentlestream” is a rate of flow that avoids spattering, splashing, or other aggressive manifestations on the part of the sample flow. Capand avoid excessive shaking during transport (see also Section 910).9. Prepa
47、ration of Apparatus9.1 SpectrophotometerCheck the performance of the spectrophotometer as described below. General information on themeasurement of performance of spectrophotometers is given in Practice E275.9.1.1 Wavelength AccuracyCheck the wavelength accuracy of the spectrophotometer at 220 nm, i
48、n accordance with themanufacturers instructions, for example, by means of a naphthalene solution (Warningsee 6.5Warningsee 6.5) in a 10-mmcell. If the scale reading at the observed band maximum differs by more than 0.3 nm from 220.6 nm (wavelength of naphthaleneband maximum), measure the absorbance
49、in the actual procedure (Section 1011) at a wavelength setting of 0.6 nm below the valuefound for the naphthalene band maximum.9.1.1.1 Alternatively, wavelength accuracy may be checked using the calibrated holmium oxide filter (6.2). Naphthalene is thepreferred material for this purpose but holmium oxide is a sufficient alternative.NOTE 6Since the absorbance of monoethylene glycol rises considerably at wavelengths shorter than 220 nm, it is essential that the wavelengthposition in this region is accurately set.6 Available from Merck KGaA, Frank
