1、Designation: D982 05 (Reapproved 2009)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 indicate
2、s 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 the determination of n
3、itrogenous organic materials in paper and paperboard, which typically areused to reduce the thermal degradation of the cellulose in the paper and paperboard.1.2 The nitrogen determination by this method does not include the nitrogen in nitro compounds, nitrates, nitrites, azo,hydrazine, cyanide, or
4、pyridine ring-type compounds, none of which are normally found in paper and paperboard. There is noknown modification of the method that is applicable to all nitrogenous compounds.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this sta
5、ndard.2. Referenced Documents2.1 ASTM Standards:2D585 Practice for Sampling and Accepting a Single Lot of Paper, Paperboard, Fiberboard, and Related Product (Withdrawn2010)3D644 Test Method for Moisture Content of Paper and Paperboard by Oven Drying (Withdrawn 2010)33. Summary of Test Method3.1 This
6、 test method is a modification of the well-known Kjeldahl procedure. In this test method, compounds that yield theirnitrogen as ammonia are digested with concentrated sulfuric acid, using sodium sulfate to raise the boiling point, and mercuricoxide as a catalyst. The organic matter is destroyed and
7、the nitrogen is fixed as ammonium sulfate in the excess acid.4. Significance and Use4.1 The purpose of this test method is to determine the amount of organic nitrogen present within a sample of electricalinsulation paper or paperboard. Nitrogen content is used to determine if the paper or paperboard
8、 has been chemically treated towithstand higher than normal operating temperatures. Such a paper or paperboard is referred to in the industry as “thermallyupgraded.” A paper or paperboard that is thermally upgraded can withstand higher operating temperatures and allow the electricalequipment to have
9、 a longer useful life span.5. Apparatus5.1 Kjeldahl Apparatus, with 500 or 800-mL flask and a digestion rack, an efficient bulb or scrubber type of trap to ensure thatno nonvolatile alkali is carried over, the trap being connected to the flask with a rubber stopper and to the water-cooled condenserf
10、ollowing, with rubber tubing. The condenser tube shall be made of alkali-resistant glass or block tin with the discharge endconnected to a bent glass delivery tube, the lower end of which is drawn out to a bore of about 3 mm.5.2 Other Apparatus500-mL Erlenmeyer flask, 100-mL graduated cylinder, 50-m
11、L buret, and mossy zinc or glass beads forthe flask to prevent bumping.1 This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of SubcommitteeD09.01 on Electrical Insulating Products.Current edition approve
12、d Oct. 1, 2009Nov. 1, 2016. Published February 2010November 2016. Originally approved in 1948. Last previous edition approved in 20052009as D982 05.D982 05 (2009). DOI: 10.1520/D0982-05R09.10.1520/D0982-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer S
13、ervice at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide
14、 the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the sta
15、ndard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Reagents6.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it i
16、s intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.4 Other grades are also acceptable, provided it is first ascertained that the reagent is of sufficientlyhigh purity to perm
17、it its use without lessening the accuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean distilled water or water ofequal purity.6.3 Boric Acid and Indicator SolutionDissolve 43 g of boric acid (H3BO3) (free from borax), 6 mL of me
18、thyl red indicator,and 4 mL of methylene blue indicator, each 0.1 g in 100 mL of 95 % ethyl alcohol, per litre of freshly distilled water. Keep thesolution in a borosilicate glass bottle. It is stable for at least 6 months.NOTE 1An alternative indicator mixture preferred by some for the boric acid s
19、olution is 2 mL of methyl red and 10 mL of bromcresol green, each0.1 percent solution, in a 95 % ethanol (1)5.6.4 Mercuric Oxide, HgO.6.5 Sodium Hydroxide Solution (approximately 50 weight percent)Dissolve 1030 g of sodium hydroxide (NaOH) in 1 L ofwater.6.6 Sodium Sulfate, anhydrous, powdered Na2SO
20、4.6.7 Sodium Thiosulfate Solution (80 g/litreL)Dissolve 80 g 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 0.1 N solution of H2SO4 and standardize.NOTE 2The substitution of a
21、0.1 N hydrochloric acid (HCl) solution is satisfactory.7. Sampling7.1 Obtain the sample to be tested in accordance with Practice D585.8. Test Specimen8.1 From the sample of the paper or paperboard, weigh, to the nearest 5 mg, a 2-g specimen consisting of small strips or piecesabout 1 cm2. At the sam
22、e time, weigh a specimen for the determination of moisture in accordance with Test Method D644.9. Procedure9.1 Transfer the test specimen to the Kjeldahl flask and add 10 g of Na2SO4, 0.7 g of HgO, and 25 mL of H2SO4 (sp gr 1.84).It is convenient to premix the Na2SO4 and the HgO. Agitate gently unti
23、l all the specimen is wet by the acid. Support the flask inan inclined position in a well-ventilated hood and heat the contents with a small flame or electric heater, taking care not to applyheat to the flask above the liquid level.An asbestos-cement board with a hole cut to the proper diameter for
24、the flask is suggested.At first the mixture will froth and turn black. Heat cautiously until frothing has ceased; then increase the heat until the mixtureboils gently. The black color gradually fades through brown to a colorless or almost colorless solution. Continue heating for about1 h after the s
25、olution becomes colorless.NOTE 3To minimize the inevitable acid condensation in the hood with this procedure, remove most of the acid fumes through a glass tube connectedto a water aspirator.9.2 Allow the solution to cool. It usually will solidify upon cooling to room temperature. When the solution
26、starts to solidifyor has cooled to room temperature, cautiously add about 300 mL of water and 25 mL of the Na2SO4 solution to precipitate themercury. Allow to stand 5 to 10 min with occasional shaking.NOTE 4It has been reported that mercury sometimes volatilizes and amalgamates with tin condenser tu
27、bes commonly used in the Kjeldahl apparatus.If the solution is allowed to stand a few minutes after the addition of the Na2SO4 solution, volatilization of the mercury is likely to be negligible (2)9.3 Add 50 mL of the boric acid and indicator solution to a 500-mL Erlenmeyer flask, connect the glass
28、delivery tube to thedischarge end of the condenser, and adjust the assembly so the tube barely dips beneath the surface of the acid.9.4 Add the anti-bumping material to the flask, be sure the bulb trap is properly connected to the condenser, and quickly andcarefully pour 55 mLof cold NaOH solution d
29、own the side of the flask so that it will not mix at once with the acid nor subsequently4 Reagents Chemicals, American Chemical Society Specifications,” Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by theAmerican Chemical Society, see “Reagent Chemicals an
30、d Standards,” by Joseph Rosin, D. Van Nostrand Co., Inc., New York, NY, and the “United States Pharmacopeia.”5 The boldface numbers in parentheses refer to the list of references at the end of this method.D982 162lubricate the rubber stopper. (WarningCool the acid solution to or below room temperatu
31、re before adding the NaOH solution.The addition of an ice cube, frozen from distilled water, to each flask in place of part of the 300 mL of water, is a convenientmethod of cooling.)9.5 Immediately connect the flask to the bulb trap, forcing the rubber stopper on the bulb trap tightly into the neck
32、of the flask.Swirl the flask slowly and then more rapidly in order to mix the acid with the alkali. Start heating the flask immediately and distillabout 150 mL into the receiver. Keep the temperature of the receiver below 40 C during the distillation.NOTE 5Fifty millilitres of the boric acid and ind
33、ication solution will absorb about 95 mg of nitrogen as ammonia (2). Twenty-five millilitres wouldbe sufficient to contain the nitrogen in a 2-g specimen of most papers.9.6 Disconnect the delivery tube from the end of the condenser and remove the heat from the flask. Do not remove the heatbefore dis
34、connecting the delivery tube because otherwise it is possible that some of the boric acid maywill be sucked back. Rinsethe delivery tube into the flask, dilute the contents of the flask to about 250 mL, and titrate to a pink end point (pH about 4.9) withthe 0.1 N acid. During the titration, the colo
35、r changes from green to gray to pink, the intensity of the pink increasing to red withfurther addition of acid.9.7 Make a blank determination, carrying through the entire procedure using 1 g of sucrose or dextrose in place of the paperspecimen.10. Calculation10.1 Calculate the nitrogen content of th
36、e specimen as follows:Nitrogen,percent5VN30.014!/W# 3100 (1)where:V = millilitres of standard acid (corrected for blank) required to titrate the distillate from the specimen,N = normality of the standard acid, andW = dry weight of the specimen, g.11. Report11.1 Report the amount of nitrogen as a per
37、centage of the moisture-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 Information)X1. ADDI
38、TIONAL INFORMATIONX1.1 A large number of determinations or a limited sample may make makes the Hengar method more attractive in some cases,but the results shouldare not be reported as complying with Test Method D982 in which mercuric oxide is the preferred catalyst.The method, proposed by Henwood an
39、d Garey (3), has been further perfected by the Hengar Co. of Philadelphia, Pa., who haveprovided special apparatus for it. This modification requires only about 0.1 g of sample; uses 0.02 N acid and alkali, and employs“selenized granules” as a catalyst. It is claimed that the Hengar method, using sp
40、ecial apparatus, requires only about 10 mindigestion with H2SO4. However, each operator should determine determines the minimum time of digestion necessary for completeoxidation under the conditions he employs.X1.2 Nitrates, nitro compounds, and so forth, would be expected to occur so infrequently i
41、n papers that no provision is made herefor their determination. Information on their estimation is given in the literature (4).D982 163REFERENCES(1) Perrin, C. H., “Rapid Modified Procedure for Determination of Kjeldahl Nitrogen,” Analytical Chemistry, ANCHA, Vol 25, No. 6, 1953, p. 968.(2) Dahl, Sv
42、erre, and Oehler, Rene, Journal of the American Leather Chemists 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 Inorganic Analysis, 2nd Ed., pp. 78
43、3792, John Wiley Methods of Sampling and Testing.(7) Bradstreet, R. B.,“A Review of the Kjeldahl Determination of Organic Nitrogen,” 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 me
44、ntionedin 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.This standard is subject to revision at any time by the responsible technical committe
45、e 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 International Headquarters. Your comments will receive careful consideration at a meetin
46、g 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 shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO
47、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). 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:/ 164
