1、Designation: D 3876 96 (Reapproved 2007)Standard Test Method forMethoxyl and Hydroxypropyl Substitution in Cellulose EtherProducts by Gas Chromatography1This standard is issued under the fixed designation D 3876; the number immediately following the designation indicates the year oforiginal adoption
2、 or, in the 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 is applicable to the determination ofmethoxyl and hydroxyp
3、ropyl substitution content in celluloseether products by a Zeisel-gas chromatographic technique.1.2 This test method is not suitable for use for the analysisof hydroxypropyl-cellulose due to its very high substitutionlevel.1.3 This standard does not purport to address all of thesafety concerns, if a
4、ny, 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 use. For specific hazardstatements, see Section 2 , 11.1.4, and 11.1.7.2. Summary of Test Method
5、2.1 When methyl cellulose or hydroxypropyl methyl cellu-lose is reacted with hydriodic acid, 1 mol of methyl iodide and1 mol of isopropyl iodide are liberated for each mole ofmethoxyl and hydroxypropoxyl that is substituted on thecellulose chain. The methyl iodide and isopropyl iodide areextracted i
6、n situ with o-xylene and quantitated by gas chroma-tography using an internal standard technique.3. Significance and Use3.1 This test method determines the methoxyl and hydrox-ypropoxyl content of cellulose ethers by a Zeisel-gas chro-matographic technique.3.2 Substitution levels affect solution pro
7、perties, rheology,viscosity, and many other properties of the polymer.4. Apparatus4.1 Gas Chromatograph,2with thermal conductivity detec-tor and heated injection port.4.2 Electronic Integrator.34.3 Stainless Steel Tubing,49.5 mm in outside diameter and1981 mm in length, packed with reagent in 5.8.4.
8、4 Syringes, 10 and 100 L.4.5 Reaction Vials, Caps, and Heating Block.55. Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the Am
9、erican Chemical Society,where such specifications are available.6Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 o-Xylene, ACS.5.3 Toluene, ACS.5.4 Iodomethane, 99 % min.
10、5.5 2-Iodopropane, 97 % min.5.6 Hydriodic Acid (sp. gr. 1.69 to 1.70)57%.5.7 Acetone.5.8 Packing Material.76. Hazards6.1 Safety precautions must be taken for handling of hydri-odic acid.6.2 During the reaction, the glass vials are under pressure.Exercise caution in handling the hot vials.7. Sampling
11、7.1 A specific sampling method is currently under study bythe subcommittee.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.36 on Cellulose and Cellulose Derivatives.Current
12、 edition approved June 1, 2007. Published August 2007. Originallyapproved in 1979. Last previous edition approved in 2001 as D 3876 96 (2001).2Hewlett-Packard Model 5700, available from Hewlett-Packard, Route 41, StarrRd, P.O. Box 900,Avondale, PA19311, has been found satisfactory for this purpose.3
13、Hewlett-Packard Model 3380 has been found satisfactory for this purpose.4Tubing from Supelco, Inc., Supelco Park, Bellefonte, PA 16823 has been foundsatisfactory for this purpose.5Reacti-therm Heating module, Reacti-Block Reacti-vials and Mininert valvetops from Pierce Chemical Co., Box 117, Rockfor
14、d, IL 61105 have been foundsatisfactory 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 Society, see Analar Standards for LaboratoryChemicals, BDH Lt
15、d., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.7Columns packed with 10 % SP2100 on 100/120 Supelcoportt have been foundsatisfactory for this purpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO B
16、ox C700, West Conshohocken, PA 19428-2959, United States.8. Apparatus Preparation and Conditioning8.1 Install prepackaged columns in the chromatograph andcondition them by heating to 150C over 1 h and then holdingat temperature for 16 h. Then set the chromatograph asfollows:8Oven temperature 130C is
17、othermalInjection port temperature 200CDetector temperature 250CDetector current 170 mAAttenuation 1Carrier gas heliumColumn A 20 mL/minColumn B 20 mL/minNOTE 1The conditions used here were determined to be optimum forthe column used. Optimum conditions should be determined for eachcolumn on an indi
18、vidual basis.8.2 Integrator:8.2.1 Settings:8Attenuation 3Chart autoChart speed 1.0 cm/in.Area reject offSlope sensitivity must be determined8.2.2 Approximate component retention times:Minutes Component3.00 methyl iodide5.00 isopropyl iodide7.00 toluene (internal standard)13.00 o-xylene9. Preparation
19、 of Standard Solutions9.1 Internal Standard Solution (25 mg toluene/ml o-xylene):9.1.1 Weigh a 100-mL volumetric flask containing 10 mL ofo-xylene to the nearest 0.01 g.9.1.2 Add 2.50 6 0.01 g of toluene.9.1.3 Dilute with o-xylene to 100 mL.9.2 Calibration Standard Solution:9.2.1 Add 2.0 mL of 57 %
20、hydriodic acid.9.2.2 Pipet 2.0 mL of the internal standard solution into thevial and cap with a serum stopper or septum top.99.2.3 Weigh vial and contents to nearest 0.1 mg.9.2.4 Add 30 L of isopropyl iodide to the vial through theseptum top with a syringe. Weigh and record the amount ofisopropyl io
21、dide added to nearest 0.1 mg.9.2.5 Add 90 L of methyl iodide to the vial with a syringe.Weigh and record the amount added to nearest 0.1 mg.9.2.6 Mix the contents well.9.2.7 Convert the alkyl iodides into their respective alkoxylequivalents using the following equations:mg methoxyl 5 g methyl iodide
22、 3S31 3 1000142D(1)mg hydroxy propoxyl 5 g propyliodide 3S75 3 1000170D(2)mg toluene 5 internal standard solution concentrated 3 4 ml (3)10. Calibration of Electronic Integrator1010.1 Inject 1 L of the upper layer of the prepared standardsolution (9.2) into the gas chromatograph and start the elec-t
23、ronic integrator.10.1.1 Calibrate in accordance with the manufacturersinstructions.10.2 In the event an electronic integrator is not available thepeak areas can be measured manually and a factor determinedfor each component can be obtained using the followingequation:F 5A 3 BC 3 D(4)where:A = weight
24、 of the component in the standard solution, mg,B = peak area of the internal standard solution, toluenefrom the standard run,C = peak area of the component from the standard run,D = weight of the internal standard solution, mg, andF = component response factor.11. Procedure11.1 Sample Preparation:11
25、.1.1 Dry the sample at 105C (221F) for 60 min andstore in a desiccator.11.1.2 Weigh 60 to 80 6 0.1 mg into a clean 5-mLreactor-vial.11.1.3 Add 2.00 6 0.01 mL of internal standard solution(9.1).11.1.4 Add 2.00 6 0.05 mL of 57 % hydriodic acid.(WarningUse a hood, goggles, and other appropriate safetye
26、quipment. Hydriodic acid can cause systemic damage.)11.1.5 Immediately cap tightly to prevent leakage.11.1.6 Shake the specimen for approximately 30 s.11.1.7 Place the reactor-vial into a 180C (356F) heatedblock for 2 h. (WarningA possible safety hazard existsbecause the vials contain a hot corrosiv
27、e acid under pressure.)11.1.8 After 2-h heating time, remove the specimen andplace in the hood to cool for about 45 min. The specimen willseparate into two layers.11.1.9 If leakage has occurred (which will be visibly obvi-ous), discard the sample and repeat the analysis.12. Analysis12.1 Enter into t
28、he integrator the milligrams of specimenand toluene internal standard used in the preparation of thespecimen.12.1.1 This can be calculated from the concentration of theinternal standard solution.12.2 Inject 2 L of the upper layer of the specimen into thegas chromatograph and immediately start the in
29、tegrator.13. Calculation13.1 The integrator printout records the methoxyl or hy-droxypropoxyl substitution, or both, in weight percent.8These settings were used with the Hewlett-Packard Model 3380 Integrator.Other units may require different settings.9Mininert valve tops from Pierce Chemical Co., Bo
30、x 117, Rockford, IL 61105have been found satisfactory for this purpose.10The Hewlett-Packard 3380 has been found satisfactory for this purpose. Otherelectronic integrators may require a different calibration technique.D 3876 96 (2007)213.2 If an electronic integrator is not available the peakareas c
31、an be measured manually and the alkoxyl substitutionmay be calculated using the following equation:% 5G 3 F 3 H 3 100I 3 J(5)where:G = peak area of the component from the specimen run,F = component response factor obtained in 13.2,H = weight of the toluene internal standard in the speci-men, mg,I =
32、peak area of the internal standard from the specimenrun, andJ = specimen weight, mg.14. Precision and Bias14.1 PrecisionThe data using an electronic integratorshow an average relative precision of 1.7 % for methoxylsubstitution (26 % level) and 5.4 % for hydroxypropyl substi-tution (0.3 to 10 % leve
33、l) at the 95 % confidence limit 2s.14.2 Interlaboratory Test Data.1114.3 BiasNo justifiable statement on bias of this proce-dure can be made because no suitable reference material exists.15. Keywords15.1 cellulose ethers; gas chromatography; hydroxypropyl;methoxylASTM International takes no position
34、 respecting 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.T
35、his standard 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 In
36、ternational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address show
37、n below.This 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), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).11Available from ASTM Headquarters. Request RR:D23-1000.D 3876 96 (2007)3
