1、Designation: E1616 08Standard Test Method forAnalysis of Acetic Anhydride Using Gas Chromatography1This standard is issued under the fixed designation E1616; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. 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 describes the determination of assayand impurities in acetic anhydride by gas chromatography. Theacetic anhydride
3、 should be at least 95 % pure.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.3 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
4、 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardsstatements see Section 9.2. Referenced Documents2.1 ASTM Standards:2E355 Practice for Gas Chromatography Terms and Relation-ships3. Terminology
5、3.1 DefinitionsFor definitions of terms used in this testmethod, see Practice E355.4. Summary of Test Method4.1 The sample is injected onto a gas chromatographiccolumn. The components are separated as they pass throughthe column with helium carrier gas, their presence in theeffluent is detected by a
6、 flame ionization detector, and recordedas a chromatogram. The concentrations of sample componentsare calculated as weight percentages using area normalization.5. Significance and Use5.1 This test method provides for the determination of assayand impurities in acetic anhydride. Acetic anhydride is u
7、sed asan intermediate in many chemical processes. Its relativeconcentration affects the efficiency of these processes. This testmethod provides a test procedure for assay and impurityspecification acceptance as well as manufacturing control.6. Interferences6.1 This test method describes the chromato
8、graphic separa-tion of possible impurities in acetic anhydride. Other impuritiescould coelute with the known components and cause aninterference. Therefore, an efficient gas chromatographic col-umn in good condition should be used in order to ensure thenecessary chromatographic separations and prope
9、r peak shapesso that good quantitative data may be obtained.6.2 This analysis is based upon the assumption that allcomponents are eluted from the gas chromatographic column.7. Apparatus7.1 Gas ChromatographAny gas chromatographequipped with a flame ionization detector and a split injectionsystem for
10、 use with capillary columns that can be operated atthe conditions given in Table 1.7.2 ColumnThe column must give satisfactory resolutionand proper peak shapes for the components listed in Fig. 1.Table 1 contains a description of a column that has been foundsatisfactory.7.3 Recorder/IntegratorElectr
11、onic integration is recom-mended for this analysis.7.4 Syringe, 10-L capacity.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the Am
12、erican Chemical Society wheresuch specifications are available.3Other grades may be used,1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.16 on Industrial and Specialty Product Standard
13、s.Current edition approved April 1, 2008. Published May 2008. Originallyapproved in 1994. Last previous edition approved in 2002 as E1616 94 (2002)1.DOI: 10.1520/E1616-08.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Ann
14、ual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society,
15、 see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Har
16、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesNOTICE: This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International (www.astm.org) for the latest information1provided it is first ascertained that the reagent is of sufficiently
17、high purity to permit its use without lessening the accuracy ofthe determination.8.2 High-Purity Acetic Anhydride (99.8 % or GreaterPurity)It is important that the acetic anhydride used toprepare calibration standards be as pure as possible. If theacetic anhydride specified by this test method is no
18、t suitable forstandard preparation, it should be redistilled prior to use oranother source found. Note that American Chemical Societyreagent grade acetic anhydride may not be sufficiently pure forthis procedure. Its titration assay will include other anhydridespresent as well as acetic anhydride.8.3
19、 Carrier GasChromatographic-grade helium.8.4 Detector Gas, airBreathing quality grade.8.5 Detector Gas, hydrogen99.95 % grade.8.6 Pure compounds for calibration could include aceticacid, ethylidene diacetate, mesityl oxide, and acetonitrile. Thepurity of all reagents should be 99 % or greater. If th
20、e purity isless than 99 %, the concentration and identification of impuri-ties must be known so that the composition of the standard canbe adjusted for the presence of the impurities.8.7 Propionic anhydride and propionic acid are not includedin the calibration of this test method. The propionic anhy
21、drideor propionic acid would react over time to form the mixedanhydride, acetic-propionic anhydride.9. Hazards9.1 Consult current Occupational Safety and Health Admin-istration (OSHA) regulations and suppliers Material SafetyData Sheets for all materials used in this test method.9.2 Acetic anhydride
22、 is a corrosive, both as a liquid and avapor. It is severely damaging to the eyes and skin. It can causedelayed burns if not removed immediately.9.3 Acetic anhydride is combustible. Its vapor is flammablein the range from 2.7 to 10.3 volume % in air. Possible ignitionsources shall be avoided.9.4 War
23、ningAcetic anhydride reacts violently with wa-ter. Handle and dispose of all samples so as to minimize anycontact with water.10. Preparation of Apparatus10.1 Follow the manufacturers instructions for mountingand conditioning the column into the chromatograph andadjusting the instrument to the condit
24、ions described in Table 1.Allow sufficient time for the equipment to reach equilibrium.11. Calibration11.1 Prior to standard preparation, the acetic anhydride usedto prepare the calibration standard must be analyzed todetermine purity. It is difficult to obtain acetic anhydride that isfree of detect
25、able levels of acetic acid; however, withpurification, the amount of acetic acid in the anhydride can beminimized. To perform this blank run, inject 1.0 L of theacetic anhydride onto the chromatographic column. Analyzethe blank in accordance with the conditions specified in Table1. If any impurity i
26、s present at a concentration of greater than0.05 % by area, it is advisable to purify the acetic anhydrideprior to use.11.1.1 The most likely impurity to remain in aceticanhydride, even after purification, is acetic acid. Retain theresults of this blank run for later use in the determination ofrespo
27、nse factors for the calibrated components noted in this testmethod.11.1.2 Relative retention times for possible components aregiven in Table 2 and a chromatogram is shown in Fig. 1.11.2 Acalibration standard should be prepared containing atleast acetic acid and acetic anhydride. Other components may
28、be calibrated as needed. Approximate amounts are given inTable 3.11.2.1 During standard preparation, the exact amounts of allcomponents shall be recorded.11.3 After analyzing the acetic anhydride blank, analyze thecalibration standard described in 11.2. Inject 1.0 L of thestandard onto the chromatog
29、raphic column. Analyze the stan-dard in accordance with the conditions specified in Table 1.11.4 Calculate response factors to four decimal places for allcomponents relative to acetic anhydride using the followingequation:Fx5Wx!Rs!Ws!Rx2 Rb!(1)where:Fx= response factor for Compound X relative to ace
30、ticanhydride,Wx= weight of Compound X, g,Rs= peak response of acetic anhydride,Ws= weight of acetic anhydride, g,Rx= peak response of Compound X in the standard, andRb= peak response of Compound X in the blank.TABLE 1 Instrument Conditions for Acetic Anhydride AnalysisColumn:Tubing fused silicaStati
31、onary phase cross-linked methyl siliconeFilm thickness, m 0.52Length, m 50Inside diameter, mm 0.32Temperature, C:Inlet 250Detector 250Column 80Carrier Gas:HeliumInjection System:Split injection; 100:1 split ratioDetector:Flame ionizationDetector Gases, mL/min:Hydrogen 30Air 350Helium, makeup 30E1616
32、 082The only components for which response factors are deter-mined are acetic acid, ethylidene diacetate, acetonitrile, andmesityl oxide. All other components are assigned relativeresponse factors of 1.0000.11.5 It is advisable that the determination of responsefactors be made on the basis of duplic
33、ate analyses.11.6 Response factors should be checked after any percep-tible change in column or instrument performance.12. Procedure12.1 Inject 1.0 L of sample onto the chromatographiccolumn.12.2 Record and integrate the chromatogram using theconditions given in Table 1.12.3 A typical chromatogram o
34、f acetic anhydride spikedwith known impurities is shown in Fig. 1.13. Calculation13.1 Calculate the concentrations of sample componentsusing the following equation:Cx,% mass m/m! 5Fx!Rx!100!(Rx!Fx!(2)where:Cx= Compound X, % mass (m/m),Rx= peak response of Compound X,Fx= relative response factor of C
35、ompound X deter-mined in 11.4, and RxFx= sum of the individual component peak responses(Rx) multiplied by their relative response factors(Fx).14. Report14.1 Report the following information:14.1.1 Individual components to the nearest 0.01 % mass(m/m).14.1.2 For concentrations of impurities less than
36、 0.01 %mass (m/m), report as 0.01 % mass (m/m).14.1.3 Acetic anhydride content to the nearest 0.01 % mass(m/m).15. Precision and Bias15.1 Precision:15.1.1 The precision data given in Table 4 were performedin one laboratory. An interlaboratory study to determinerepeatability and reproducibility has n
37、ot been completed.15.1.2 The precision of this test method on samples ofapproximately 95 % mass (m/m) acetic anhydride was deter-mined. Twenty samples of acetic anhydride were split into twoFIG. 1 Chromatogram of Acetic Anhydride Spiked with Possible ImpuritiesTABLE 2 Relative Retention Times for Po
38、ssible Impurities inAcetic AnhydrideComponent Relative Retention TimeKetene 0.62Acetonitrile 0.67Acetic acid 0.75Propionic acid 0.91Acetic anhydride 1.00Mesityl oxide 1.25Acetic propionic anhydride 1.29Ethylidene diacetate 1.90Propionic anhydride 1.98TABLE 3 Calibration Standard Composition for Acet
39、ic AnhydrideAnalysisComponent Weight%Acetic acid 0.50 to 1.5Acetic anhydride 98.0 to 99.5Acetonitrile 0.01 to 0.05Ethylidene diacetate 0.01 to 0.05Mesityl oxide 0.01 to 0.05E1616 083aliquots. These 40 samples were randomly analyzed by any of16 analysts using one gas chromatograph and a chromato-grap
40、hic data system over a two week period in one laboratory.These results are given for Sample 1 in Table 4.15.1.3 The precision of this test method on samples ofgreater than 99 % mass (m/m) acetic anhydride was deter-mined. Thirty samples of acetic anhydride were split into twoaliquots. These 60 sampl
41、es were randomly analyzed by any of20 analysts using one gas chromatograph and a chromato-graphic data system over a 20 day period in one laboratory. Theresults are given for Sample 2 in Table 4.15.2 BiasSince there is no accepted reference materialsuitable for determining the bias for this test met
42、hod, bias hasnot been determined.16. Keywords16.1 acetic anhydride; anhydride; gas chromatographySUMMARY OF CHANGESCommittee E15 has identified the location of selected changes to this standard since the last issue(E161694(2002)1) that may impact the use of this standard.(1) Updated units of measure
43、 to comply with the InternationalSystem of Units (SI).(2) Addition of numbered section in Scope, 1.2, stating the SIunits are to be considered standard.(3) Corrected spelling of “resonse” to “response” in 11.4.(4) Addition of Summary of Changes section.ASTM International takes no position respecting
44、 the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standar
45、d is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International
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47、s standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax),
48、 or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 4 Precision DataComponentAverageConcentration, %StandardDeviation95 %Limits, %Sample 1Acetic acid 4.24 0.039 0.11Acetic anhydride 95.24 0.043 0.12Acetic-propionic anhydride .20 0.004 0.01Ethylidene diacetate 0.07 0.003 0.01Sample 2Acetic anhydride 99.82 0.032 0.09E1616 084
