ASTM D982-2005(2009) 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

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1、Designation: D982 05 (Reapproved 2009)An 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 D982; the number immediately following the

2、 designation indicates 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers t

3、he determination 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,hyd

4、razine, cyanide, 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.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are inc

5、luded in thisstandard.2. Referenced Documents2.1 ASTM Standards:2D585 Practice for Sampling and Accepting a Single Lot ofPaper, Paperboard, Fiberboard, and Related ProductD644 Test Method for Moisture Content of Paper andPaperboard by Oven Drying3. Summary of Test Method3.1 This test method is a mod

6、ification of the well-knownKjeldahl procedure. In this test method, compounds that yieldtheir nitrogen as ammonia are digested with concentratedsulfuric 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

7、 ammonium sulfate in theexcess acid.4. Significance and Use4.1 The purpose of this test method is to determine theamount of organic nitrogen present within a sample of electri-cal insulation paper or paperboard. Nitrogen content is used todetermine if the paper or paperboard has been chemicallytreat

8、ed to withstand higher than normal operating tempera-tures. Such a paper or paperboard is referred to in the industryas “thermally upgraded.” A paper or paperboard that is ther-mally upgraded can withstand higher operating temperaturesand allow the electrical equipment to have a longer useful lifesp

9、an.5. Apparatus5.1 Kjeldahl Apparatus, with 500 or 800-mL flask and adigestion rack, an efficient bulb or scrubber type of trap toensure 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 tubi

10、ng. Thecondenser tube shall be made of alkali-resistant glass or blocktin with the discharge end connected to a bent glass deliverytube, 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 glas

11、s beadsfor the flask to prevent bumping.6. Reagents6.1 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 American Chemical Society,where

12、such specifications are available.3Other grades are alsoacceptable, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understo

13、od to mean distilled water or water ofequal purity.6.3 Boric Acid and Indicator SolutionDissolve 43 g ofboric acid (H3BO3) (free from borax), 6 mL of methyl redindicator, and 4 mL of methylene blue indicator, each 0.1 g in1This test method is under the jurisdiction of ASTM Committee D09 onElectrical

14、 and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.19 on Dielectric Sheet and Roll Products.Current edition approved Oct. 1, 2009. Published February 2010. Originallyapproved in 1948. Last previous edition approved in 2005 as D982 05. DOI:10.1520/D0982-05R09.2Fo

15、r 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 to the standards Document Summary page onthe ASTM website.3Reagents Chemicals, American Chemical Society Specifications,”

16、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. Van Nostrand Co., Inc., New York, NY, and the “United StatesPharmacopeia.”1Copyright ASTM International, 100 Barr Harbor

17、 Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.100 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 theboric acid solut

18、ion is 2 mL of methyl red and 10 mL of bromcresol green,each 0.1 percent solution, in a 95 % 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

19、 Sodium Thiosulfate Solution (80 g/litreL)Dissolve 80g of sodium thiosulfate (Na2S2O35H2O) in 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 hyd

20、rochloric acid (HCl) solutionis satisfactory.7. Sampling7.1 Obtain the sample to be tested in accordance withPractice D585.8. 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

21、 a specimen for thedetermination of moisture in accordance with Test MethodD644.9. Procedure9.1 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

22、wet by the acid. Supportthe flask in an inclined position in a well-ventilated hood andheat 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.A

23、t first the mixture will froth and turnblack. Heat cautiously until frothing has ceased; then 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

24、.NOTE 3To minimize the inevitable acid condensation in the hoodwith this procedure, remove 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 co

25、oled to room temperature, cautiously addabout 300 mL of water and 25 mL of the Na2SO4solution 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 Kjelda

26、hlapparatus. If the solution is allowed to stand a few minutes after theaddition of the Na2SO4solution, 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 o

27、f the condenser, and adjust the assembly sothe tube barely dips beneath the surface of the 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

28、will not mix at once with the acid norsubsequently lubricate the rubber stopper. (WarningCoolthe 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 m

29、ethod of cooling.)9.5 Immediately connect the flask to the bulb trap, forcingthe rubber stopper 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 t

30、he receiver. Keep the tempera-ture of the receiver below 40 C during the distillation.NOTE 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 mostpaper

31、s.9.6 Disconnect the delivery tube from the end of thecondenser and remove the heat from the 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 content

32、sof the flask to about 250 mL, and titrate to a pink end point (pHabout 4.9) with the 0.1 N 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 entirepro

33、cedure using1gofsucrose or dextrose in place of the paperspecimen.10. Calculation10.1 Calculate 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

34、,N = normality of the standard acid, andW = dry weight of the specimen, g.11. Report11.1 Report 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 nitrog

35、enpresent. Also report the factor used.4The boldface numbers in parentheses refer to the list of references at the end ofthis method.D982 05 (2009)212. Keywords12.1 nitrogen; paper; paperboardAPPENDIX(Nonmandatory Information)X1. ADDITIONAL INFORMATIONX1.1 A large number of determinations or a limit

36、ed samplemay make the Hengar method more attractive in some cases,but the results should not be reported as complying with TestMethod D982 in which mercuric oxide is the preferred catalyst.The method, proposed by Henwood and Garey (3), has beenfurther perfected by the Hengar Co. of Philadelphia, Pa.

37、, whohave provided special apparatus for it. This modificationrequires only about 0.1 g of sample; uses 0.02 N acid andalkali, 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 op

38、erator should determine the minimum time of digestionnecessary for complete oxidation under the 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-mati

39、on is given in the literature (4).REFERENCES(1) Perrin, C. H., “Rapid Modified Procedure for Determination 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)

40、Henwood, A., and Garey, R. M., Journal of the Franklin Institute,JFINA, Vol 122, 1940, p. 531.(4) 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 Determinati

41、on of OrganicNitrogen,” Chemical Reviews, CHREA, Vol 27, 1940, p. 331.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 are expressly advised that determination of the validity of a

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