ASTM D982-2005 Standard Test Method for Organic Nitrogen in Paper and Paperboard《纸和纸板中有机氮的标准试验方法》.pdf

1、Designation: D 982 05An American National StandardTechnical Association of Pulpand Paper IndustryStandard Method T 418 os-61Standard Test Method forOrganic Nitrogen in Paper and Paperboard1This standard is issued under the fixed designation D 982; the number immediately following the designation ind

2、icates the year 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determinatio

3、n of nitrog-enous organic materials in paper and paperboard, whichtypically are used to reduce the thermal degradation of thecellulose in the paper and paperboard.1.2 The nitrogen determination by this method does notinclude the nitrogen in nitro compounds, nitrates, nitrites, azo,hydrazine, cyanide

4、, or pyridine ring-type compounds, none ofwhich are normally found in paper and paperboard. There is noknown modification of the method that is applicable to allnitrogenous compounds.2. Referenced Documents2.1 ASTM Standards:2D 585 Practice for Sampling and Accepting a Single Lot ofPaper, Paperboard

5、, Fiberboard, and Related ProductD 644 Test Method for Moisture Content of Paper andPaperboard by Oven Drying3. Summary of Test Method3.1 This test method is a modification of the well-knownKjeldahl procedure. In this test method, compounds that yieldtheir nitrogen as ammonia are digested with conce

6、ntratedsulfuric acid, using sodium sulfate to raise the boiling point,and mercuric oxide as a catalyst. The organic matter isdestroyed and the nitrogen is fixed as ammonium sulfate in theexcess acid.4. Significance and Use4.1 The purpose of this test method is to determine theamount of organic nitro

7、gen present within a sample of electri-cal insulation paper or paperboard. Nitrogen content is used todetermine if the paper or paperboard has been chemicallytreated to withstand higher than normal operating tempera-tures. Such a paper or paperboard is referred to in the industryas “thermally upgrad

8、ed.” A paper or paperboard that is ther-mally upgraded can withstand higher operating temperaturesand allow the electrical equipment to have a longer useful lifespan.5. Apparatus5.1 Kjeldahl Apparatus, with 500 or 800-mL flask and adigestion rack, an efficient bulb or scrubber type of trap toensure

9、that no nonvolatile alkali is carried over, the trap beingconnected to the flask with a rubber stopper and to thewater-cooled condenser following, with rubber tubing. Thecondenser tube shall be made of alkali-resistant glass or blocktin with the discharge end connected to a bent glass deliverytube,

10、the lower end of which is drawn out to a bore of about 3mm.5.2 Other Apparatus500-mL Erlenmeyer flask, 100-mLgraduated cylinder, 50-mLburet, and mossy zinc or glass beadsfor the flask to prevent bumping.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherw

11、ise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades are alsoacceptable, provided it is first ascertained that the reagent is ofsufficiently h

12、igh purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled water or water ofequal purity.6.3 Boric Acid and Indicator SolutionDissolve 43 g ofboric acid (H3BO3) (free from bor

13、ax), 6 mL of methyl redindicator, and 4 mL of methylene blue indicator, each 0.1 g in100 mL of 95 % ethyl alcohol, per litre of freshly distilledwater. Keep the solution in a borosilicate glass bottle. It isstable for at least 6 months.NOTE 1An alternative indicator mixture preferred by some for the

14、1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.19 on Dielectric Sheet and Roll Products.Current edition approved October 1, 2005. Published October 2005. Originallyapproved in 1948

15、. Last previous edition approved in 1971 as D 982 63(1971),which was withdrawn August 1981 and reinstated October 2005.2For 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

16、to the standards Document Summary page onthe ASTM website.3Reagents Chemicals, American Chemical Society Specifications,” Am. Chemi-cal Soc., Washington, DC. For suggestions on the testing of reagents not listed bytheAmerican Chemical Society, see “Reagent Chemicals and Standards,” by JosephRosin, D

17、. Van Nostrand Co., Inc., New York, NY, and the “United StatesPharmacopeia.”1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.boric acid solution is 2 mL of methyl red and 10 mL of bromcresol green,each 0.1 percent solution, in a 95 %

18、ethanol (1)4.6.4 Mercuric Oxide, HgO.6.5 Sodium Hydroxide Solution (approximately 50 weightpercent)Dissolve 1030 g of sodium hydroxide (NaOH) in 1L of water.6.6 Sodium Sulfate, anhydrous, powdered Na2SO4.6.7 Sodium Thiosulfate Solution (80 g/litreL)Dissolve 80g of sodium thiosulfate (Na2S2O35H2O) in

19、 1 L of water.6.8 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).6.9 Sulfuric Acid, Standard Solution (0.1 N)Prepare a 0.1N solution of H2SO4and standardize.NOTE 2The substitution of a 0.1 N hydrochloric acid (HCl) solutionis satisfactory.7. Sampling7.1 Obtain the sample to be tested in

20、 accordance withPractice D 585.8. Test Specimen8.1 From the sample of the paper or paperboard, weigh, tothe nearest 5 mg, a 2-g specimen consisting of small strips orpieces about 1 cm2.At the same time, weigh a specimen for thedetermination of moisture in accordance with Test MethodD 644.9. Procedur

21、e9.1 Transfer the test specimen to the Kjeldahl flask and add10gofNa2SO4, 0.7 g of HgO, and 25 mL of H2SO4(sp gr1.84). It is convenient to premix the Na2SO4and the HgO.Agitate gently until all the specimen is wet by the acid. Supportthe flask in an inclined position in a well-ventilated hood andheat

22、 the contents with a small flame or electric heater, takingcare not to apply heat to the flask above the liquid level. Anasbestos-cement board with a hole cut to the proper diameterfor the flask is suggested.At first the mixture will froth and turnblack. Heat cautiously until frothing has ceased; th

23、en increasethe heat until the mixture boils gently. The black colorgradually fades through brown to a colorless or almost color-less solution. Continue heating for about 1 h after the solutionbecomes colorless.NOTE 3To minimize the inevitable acid condensation in the hoodwith this procedure, remove

24、most of the acid fumes through a glass tubeconnected to a water aspirator.9.2 Allow the solution to cool. It usually will solidify uponcooling to room temperature. When the solution starts tosolidify or has cooled to room temperature, cautiously addabout 300 mL of water and 25 mL of the Na2SO4soluti

25、on toprecipitate the mercury. Allow to stand 5 to 10 min withoccasional shaking.NOTE 4It has been reported that mercury sometimes volatilizes andamalgamates with tin condenser tubes commonly used in the Kjeldahlapparatus. If the solution is allowed to stand a few minutes after theaddition of the Na2

26、SO4solution, volatilization of the mercury is likely tobe negligible (2)9.3 Add 50 mL of the boric acid and indicator solution to a500-mL Erlenmeyer flask, connect the glass delivery tube tothe discharge end of the condenser, and adjust the assembly sothe tube barely dips beneath the surface of the

27、acid.9.4 Add the anti-bumping material to the flask, be sure thebulb trap is properly connected to the condenser, and quicklyand carefully pour 55 mL of cold NaOH solution down the sideof the flask so that it will not mix at once with the acid norsubsequently lubricate the rubber stopper. (WarningCo

28、olthe acid solution to or below room temperature before addingthe NaOH solution. The addition of an ice cube, frozen fromdistilled water, to each flask in place of part of the 300 mL ofwater, is a convenient method of cooling.)9.5 Immediately connect the flask to the bulb trap, forcingthe rubber sto

29、pper on the bulb trap tightly into the neck of theflask. Swirl the flask slowly and then more rapidly in order tomix the acid with the alkali. Start heating the flask immediatelyand distill about 150 mL into the receiver. Keep the tempera-ture of the receiver below 40 C during the distillation.NOTE

30、5Fifty millilitres of the boric acid and indication solution willabsorb about 95 mg of nitrogen as ammonia (2). Twenty-five millilitreswould be sufficient to contain the nitrogen in a 2-g specimen of mostpapers.9.6 Disconnect the delivery tube from the end of thecondenser and remove the heat from th

31、e flask. Do not removethe heat before disconnecting the delivery tube because other-wise it is possible that some of the boric acid may be suckedback. Rinse the delivery tube into the flask, dilute the contentsof the flask to about 250 mL, and titrate to a pink end point (pHabout 4.9) with the 0.1 N

32、 acid. During the titration, the colorchanges from green to gray to pink, the intensity of the pinkincreasing to red with further addition of acid.9.7 Make a blank determination, carrying through the entireprocedure using1gofsucrose or dextrose in place of the paperspecimen.10. Calculation10.1 Calcu

33、late the nitrogen content of the specimen asfollows:Nitrogen, percent 5 VN 3 0.014!/W 3 100 (1)where:V = millilitres of standard acid (corrected for blank) re-quired to titrate the distillate from the specimen,N = normality of the standard acid, andW = dry weight of the specimen, g.11. Report11.1 Re

34、port the amount of nitrogen as a percentage of themoisture-free paper to the nearest 0.01.11.2 If the specific nitrogenous organic substance is known,report the amount of this substance indicated by the nitrogenpresent. Also report the factor used.12. Keywords12.1 nitrogen; paper; paperboard4The bol

35、dface numbers in parentheses refer to the list of references at the end ofthis method.D982052APPENDIX(Nonmandatory Information)X1. ADDITIONAL INFORMATIONX1.1 A large number of determinations or a limited samplemay make the Hengar method more attractive in some cases,but the results should not be rep

36、orted as complying with TestMethod D 982 in which mercuric oxide is the preferredcatalyst. The method, proposed by Henwood and Garey (3),has been further perfected by the Hengar Co. of Philadelphia,Pa., who have provided special apparatus for it. This modifi-cation requires only about 0.1 g of sampl

37、e; uses 0.02 N acidand alkali, and employs “selenized granules” as a catalyst. It isclaimed that the Hengar method, using special apparatus,requires only about 10 min digestion with H2SO4. However,each operator should determine the minimum time of digestionnecessary for complete oxidation under the

38、conditions heemploys.X1.2 Nitrates, nitro compounds, and so forth, would beexpected to occur so infrequently in papers that no provision ismade here for their determination. Information on their esti-mation is given in the literature (4).REFERENCES(1) Perrin, C. H., “Rapid Modified Procedure for Det

39、ermination ofKjeldahl Nitrogen,” Analytical Chemistry, ANCHA, Vol 25, No. 6,1953, p. 968.(2) Dahl, Sverre, and Oehler, Rene, Journal of the American LeatherChemists Assn., JALCA, Vol 46, 1951, p. 317.(3) Henwood, A., and Garey, R. M., Journal of the Franklin Institute,JFINA, Vol 122, 1940, p. 531.(4

40、) Lundell, G. E. F., Bright, H. A., and Hoffman, J. I., Applied InorganicAnalysis, 2nd Ed., pp. 783792, John Wiley Methods of Sampling andTesting.(7) Bradstreet, R. B., “AReview of the Kjeldahl Determination of OrganicNitrogen,” Chemical Reviews, CHREA, Vol 27, 1940, p. 331.ASTM International takes

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44、ddress shown 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).D982053