1、Designation: D982 16 Technical 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 designation indicates the year oforiginal ado
2、ption 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 the determination of nitrog-enous organic mater
3、ials 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, or pyridine ring-type compoun
4、ds, 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 included in thisstandard.2. Referenced Documents2
5、.1 ASTM Standards:2D585 Practice for Sampling and Accepting a Single Lot ofPaper, Paperboard, Fiberboard, and Related Product(Withdrawn 2010)3D644 Test Method for Moisture Content of Paper andPaperboard by Oven Drying (Withdrawn 2010)33. Summary of Test Method3.1 This test method is a modification o
6、f 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 ammonium s
7、ulfate 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 chemicallytreated to withs
8、tand 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 lifespan.5. Appar
9、atus5.1 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 tubing. Thecond
10、enser 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 glass beadsfor
11、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 such specif
12、ications are available.4Other 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.1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic
13、Insulating Materials and is the direct responsibility ofSubcommittee D09.01 on Electrical Insulating Products.Current edition approved Nov. 1, 2016. Published November 2016. Originallyapproved in 1948. Last previous edition approved in 2009 as D982 05 (2009).DOI: 10.1520/D0982-16.2For referenced AST
14、M 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.3The last approved version of this historical standard is referenced onwww.astm.
15、org.4Reagents 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. Van Nostrand Co., Inc., New York, NY, and the “Unite
16、d StatesPharmacopeia.”Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for t
17、heDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean distilled water or water ofequal purity.6.3 Boric Aci
18、d 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 in100 mL of 95 % ethyl alcohol, per litre of freshly distilledwater. Keep the solution in a borosilicate glass bottle. It isstable for at least
19、6 months.NOTE 1An alternative indicator mixture preferred by some for theboric acid solution is 2 mL of methyl red and 10 mL of bromcresol green,each 0.1 percent solution, in a 95 % ethanol (1)5.6.4 Mercuric Oxide, HgO.6.5 Sodium Hydroxide Solution (approximately 50 weightpercent)Dissolve 1030 g of
20、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 1 L of water.6.8 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).6.9 Sulfuric Acid, Standard Solution (0.
21、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 accordance withPractice D585.8. Test Specimen8.1 From the sample of the paper or paperboard, weigh, tothe nearest 5 m
22、g, 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 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). I
23、t 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 the contents with a small flame or electric heater, takingcare not to apply heat to the flask above the liquid level. A
24、nasbestos-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; then increasethe heat until the mixture boils gently. The black colorgradually fades through brown to a colorless or almos
25、t color-less solution. Continue heating for about 1 h after the solutionbecomes colorless.NOTE 3To minimize the inevitable acid condensation in the hood withthis procedure, remove most of the acid fumes through a glass tubeconnected to a water aspirator.9.2 Allow the solution to cool. It usually wil
26、l 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 Na2SO4solution toprecipitate the mercury. Allow to stand 5 to 10 min withoccasional shaking.NOTE 4It has been reported that mercury
27、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 Na2SO4solution, volatilization of the mercury is likely tobe negligible (2)9.3 Add 50 mL of the boric acid and indicator so
28、lution 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 acid.9.4 Add the anti-bumping material to the flask, be sure thebulb trap is properly connected to the condenser, and qu
29、icklyand 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. (WarningCoolthe acid solution to or below room temperature before addingthe NaOH solution. The addition of an ice cube, frozen fro
30、mdistilled 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 stopper on the bulb trap tightly into the neck of theflask. Swirl the flask slowly and then more rapidly in order tomix the
31、 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 5Fifty millilitres of the boric acid and indication solution willabsorb about 95 mg of nitrogen as ammonia (2). Twenty-f
32、ive 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 the flask. Do not removethe heat before disconnecting the delivery tube because other-wise it is possible that some of the
33、 boric acid will 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 acid. During the titration, the colorchanges from green to gray to pink, the intensity of the pinkincreasing to red wi
34、th 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 Calculate the nitrogen content of the specimen asfollows:Nitrogen, percent 5 VN 30.014!/W# 3100 (1)where:V = millilitres of
35、standard acid (corrected for blank) re-quired to titrate the distillate from the specimen,5The boldface numbers in parentheses refer to the list of references at the end ofthis method.D982 162N = normality of the standard acid, andW = dry weight of the specimen, g.11. Report11.1 Report the amount of
36、 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; paperboardAPPENDIX(Nonmandatory Info
37、rmation)X1. ADDITIONAL INFORMATIONX1.1 A large number of determinations or a limited samplemakes the Hengar method more attractive in some cases, butthe results are not reported as complying with Test MethodD982 in which mercuric oxide is the preferred catalyst. Themethod, proposed by Henwood and Ga
38、rey (3), has been furtherperfected by the Hengar Co. of Philadelphia, Pa., who haveprovided special apparatus for it. This modification requiresonly about 0.1 g of sample; uses 0.02 N acid and alkali, andemploys “selenized granules” as a catalyst. It is claimed thatthe Hengar method, using special a
39、pparatus, requires onlyabout 10 min digestion with H2SO4. However, each operatordetermines the minimum time of digestion necessary forcomplete oxidation under the conditions he employs.X1.2 Nitrates, nitro compounds, and so forth, would beexpected to occur so infrequently in papers that no provision
40、 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 Determination ofKjeldahl Nitrogen,” Analytical Chemistry, ANCHA, Vol 25, No. 6,1953, p. 968.(2) Dahl, Sverre, and Oehler, Rene, Journal of
41、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) Lundell, G. E. F., Bright, H. A., and Hoffman, J. I., Applied InorganicAnalysis, 2nd Ed., pp. 783792, John Wiley Methods of Sampling a
42、ndTesting.(7) Bradstreet, R. B.,“AReview of the Kjeldahl Determination 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 st
43、andard 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 a
44、ndif 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 Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,
45、 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 shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29
46、59,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). 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:/ 163
