1、Designation: D5896 96 (Reapproved 2012)Standard Test Method forCarbohydrate Distribution of Cellulosic Materials1This standard is issued under the fixed designation D5896; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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. Scope1.1 This test method covers the determination of the carbo-hydrate composition of cellulosic materials such as groundwood
3、 meal, chemically refined pulp, mechanical pulps, brown-stocks, and plant exudates (gums) by ion chromatography. Thistest method is suitable for rapid, routine testing of largenumbers of samples with high accuracy and precision. For areview of this technique, see Lee (1) .21.2 The values stated in S
4、I units are to be regarded asstandard. No other units of measurement are included in thisstandard.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 standard to establish appro-priate safety and health
5、 practices and determine the applica-bility of regulatory limitations prior to use. For hazard state-ment, see Section 8.2. Referenced Documents2.1 ASTM Standards:3D1193 Specification for Reagent WaterD1695 Terminology of Cellulose and Cellulose Derivatives3. Terminology3.1 For standard terminology
6、of cellulose and cellulosederivatives, see Terminology D1695.3.2 Abbreviations:3.2.1 ICion chromatography,3.2.2 SPEsolid phase extraction,3.2.3 PADpulsed amperometric detector,3.2.4 PEDpulsed electrochemical detector,3.2.5 mMmillimolar.4. Summary of Test Method4.1 IC analysis of cellulosics requires
7、 the following opera-tions:(1) sample preparation,(2) total hydrolysis,(3) dilution,(4) SPE,(5) ion chromatographic analysis, and(6) calibration/calculation.5. Significance and Use5.1 This test method requires total hydrolysis of carbohy-drate material to monosaccharides, and is thus applicable toan
8、y cellulosic or related material that undergoes substantialhydrolysis, including cellulose derivatives such as celluloseacetate.5.2 The carbohydrate composition of a cellulosic materialcan be expressed on the basis of the total initial sample, or onthe basis of the carbohydrate portion of the sample
9、. The formerrequires quantitative handling and may require special knowl-edge of the other components present in order to establish theabsolute carbohydrate level or determine individual woodhemicelluloses such as galactoglucomannan, etc. Since thesolid portion of purified pulps is almost all carboh
10、ydrate(98 + %), the latter basis is often used to express the carbo-hydrate distribution as a percent.5.3 If heated under alkaline conditions, isomeric sugars maybegin to appear in the chromatogram. The major impuritypresent in purified pulps is saccharinic acids. These acidiccomponents, and other a
11、nions such as sulfate, carbonate, andacetate are removed by a strong base anion exchange SPE, andwould need to be determined separately to get a more exactcarbohydrate distribution.6. Apparatus6.1 Blender.6.2 Screw Cap Culture Tubes, 25 by 150 mm, outsidediameter.6.3 Refrigerator.6.4 Pressure Cooker
12、.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 edition approved June 1, 2012. Published August 2012. Originallyapproved
13、in 1996. Last previous edition approved in 2007 as D5896 - 96 (2007).DOI: 10.1520/D5896-96R12.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at se
14、rviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.5 SPE Cartridges.6.6 Water Bath.6.7 Ion Chromatograp
15、h.6.8 Moisture Balance.6.9 Hot Plate.6.10 Pipets.TOTAL HYDROLYSIS7. Reagents and Materials7.1 Sulfuric Acid (72 6 0.1 weight %): To 1 volume ofwater, add slowly while stirring vigorously 2 volumes ofconcentrated sulfuric acid (sp gr 1.84). Standardize against analkaline standard, and adjust to 72 6
16、0.1 weight %.8. Hazards8.1 Precaution: Wear eye protection and chemical resistantgloves while working with strong acid.9. Summary of Procedure9.1 The total hydrolysis of cellulosic material requires aprimary hydrolysis with strong mineral acid followed by asecondary hydrolysis in dilute acid. The pr
17、imary hydrolysisresults in the formation of a mixture of oligosaccharides; thesecondary hydrolysis completes the conversion to monomericsugars.10. Sampling, Test Specimens, and Test Units10.1 Extract wood samples with ethanol to remove extrac-tives, then grind in a Wiley mill to pass a 40-mesh scree
18、n.Disintegrate (fluff) dry pulp or paper samples in a blender.Determine the moisture content using a moisture balance orsimilar device.11. Procedure11.1 Add 1 mL of cold, 72 % sulfuric acid to 100 mg ofcellulose (bone dry basis) in a 25 by 150-mm screw top culturetube. (For wood samples, adjust samp
19、le size upward based onestimated polysaccharide content of the sample.)11.2 Mix with glass rod, and place in refrigerator overnight(with glass rod in place).11.3 Heat samples (with stirrers in place) at 30C for 1 h.11.4 Remove glass rod and rinse while adding 28 mL ofwater to each tube and, with cap
20、s on, place samples in apressure cooker, and heat to 15 psi.11.5 Maintain pressure at 15 psi for 1 h.11.6 Cool to room temperature and dilute the sample toavoid overloading the analytical column (usually a dilutionbetween 1 to 20 and 1 to 50 is adequate). Dilute with watercontaining a standard such
21、that its concentration in the dilutedsample is 2 ppm. D-Fucose (6-deoxy-D-galactose) or 2-deoxy-D-glucose make good internal standards.11.7 Neutralization of the sample is not required, butimproved resolution may occur if the sample is adjusted to pH66.5 during the dilution step. Neutralization is r
22、ecommendedif the sample is to be stored before analysis.11.8 Prepare an anion exchange SPE cartridge with 5 mL ofwater, pass 5 mL of sample through the cartridge, discardingthe first 3 mL, and use the remaining 2 mL to fill a 0.5-mLinjection vial.Additional 0.5-mL injection vials may be filled ifmul
23、tiple injections are planned.11.9 Inject the samples onto an ion chromatograph operat-ing as described in the following text.HIGH-PERFORMANCE ION CHROMATOGRAPHY12. Apparatus12.1 Ion ChromatographThis equipment can be as-sembled from the individual components, or purchased as asystem.412.2 ColumnThe
24、column must be suitable for separatingmonosaccharides and is generally protected by a suitable guardcolumn. A column packing material that works well is com-posed of 10 m beads of surface-sulfonated polystyrene/divinylbenzene (2 % crosslinked), covered with porous latexbeads containing alkyl quatern
25、ary amine functionality.13. Procedure13.1 Perform the analysis using an ion chromatograph.13.2 Inject 100 L of sample onto the analytical column.13.3 Detection is by PAD or PED in a pulsed amperometricmode using a gold working electrode.13.4 Standard pulp samples are generally run isocratically at1
26、mL/min using an eluant of 2.5 mM sodium hydroxide toobtain baseline resolution of fucose (internal standard), arab-inose, galactose, glucose, xylose, and mannose in less than 30min. If other sugars are present, it may be necessary to alter theeluant strength, or try a gradient approach.13.5 Eluant i
27、s degassed and kept under helium (nitrogenmay be substituted for helium).13.6 A 0.5-mL/min flow of 0.3-M NaOH is added after thecolumn, but prior to the detector to improve response.14. Calibration and Standardization14.1 Prepare standards of the individual sugars of interest,such as those listed in
28、 13.4, from reagent grade standards. Runthe test mixture at various concentrations ($5) such that allreal samples will have peaks that fall on the calibration linesderived from this data. Note that sample concentrations are setby the dilution ratio used in 11.6, and make sure that they aregiven in p
29、pm.14.2 Prepare a mixture of the sugars of interest, in relativeratios similar to that expected from the sample, such that it willfall within the calibration range established in 14.1. Run thissample routinely as a control that is used to establish thestandard error and control chart for the method.
30、4Lists of companies that supply this equipment can be found in buyers guidessuch as those published yearly by American Laboratory or Analytical Chemistry.D5896 96 (2012)215. Calculation or Interpretation of Results15.1 Since cellulose is composed totally of anhydroglucoseunits, the repeat unit weigh
31、t is 162. Hydrolysis of 100 mg ofcellulose would theoretically give 111.1 mg of glucose (for-mula weight (FW) = 180). Other hexoses have the samerelationship. Thus, hemicelluloses such as mannans, galactog-lucomannans, and glucomannans can be backcalculated in asimilar manner.15.2 Hemicelluloses or
32、gums that contain only pentoseshave a repeat unit weight of 132. Thus, hydrolysis of 100 mgof xylan would theoretically give 113.6 mg of xylose(FW = 150). Hemicelluloses that contain both 6-carbon and5-carbon sugars would have a repeat unit weight between 132and 162, depending on composition.15.3 In
33、 a similar manner, the composition of triacetatescould be determined and the recovery calculated based on arepeat unit weight of 288 for cellulose triacetate, and 258 forxylan triacetate.16. Report16.1 Report the following information:16.1.1 The amount of each sugar detected is reported inppm. In ad
34、dition, a distribution can be reported based on thepercent of each sugar relative to the total, omitting the internalstandard. Information on detection limits is given in Refs (2) ,(3), and (4),16.1.2 For relatively clean samples, such as bleached pulp,the percent recovery should be calculated and r
35、eported. Thepercent recovery should be between 85 to 95 %.17. Precision and Bias17.1 Interlaboratory data has not been obtained.17.2 Precision and bias (see (2) and (5) will vary with theraw materials tested. For a bleached kraft Southern pine paperpulp, the following intralaboratory results were ob
36、tained from10 replicate tests:Sugar ppm SD Percent SD, %arabinose 4.33 0.35 0.11 0.008galactose 3.51 0.44 0.09 0.010glucose 3305.93 94.86 86.95 0.184mannose 206.93 6.67 5.44 0.107xylose 281.49 6.04 7.41 0.131where SD is the sample standard deviation.17.3 BiasBias introduced by the hydrolysis procedu
37、re isnot known. Since calibration is by known standards of knownconcentration, bias has been removed from the IC determina-tion.18. Keywords18.1 carbohydrate; carbohydrate distribution; chromatogra-phy; distribution; hemicellulose; hydrolysis; ion chromatogra-phy; monosaccharides; PAD; sugarsREFEREN
38、CES(1) Lee, Y. C., Analytical Biochemistry, Vol 189, 1990, p. 151.(2) Pettersen, R. C. and Schwandt, V. H., Journal of Wood Chemistry andTechnology, Vol 11, No. 4, 1991, p. 495.(3) Dionex Corp., “Dionex Technical Note,” TN20, Dionex Corp., Sunny-vale, CA, 1989 .(4) Johnson, D. C. and LaCourse, W. R.
39、, Analytical Chemistry, Vol 62,1990, p. 589A.(5) Sullivan, J. and Douck, M., Journal of Chromatography, Vol 671, No.6, 1994, p. 339.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard
40、 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 standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif n
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43、ted 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D5896 96 (2012)3
