1、Designation: E147 61 (Reapproved 2017)Standard Specification forApparatus for Microdetermination of Nitrogen by KjeldahlMethod1This standard is issued under the fixed designation E147; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, 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 specification covers digestion and distillation ap-paratus used for the microdetermination of nitro
3、gen by theKjeldahl method, and modifications thereof at atmosphericpressure.NOTE 1This specification is based on those originally developed bythe Committee on Microchemical Apparatus, Division of AnalyticalChemistry, American Chemical Society.22. Referenced Documents2.1 ASTM Standards:3E124 Specific
4、ation for Weighing and Drying Apparatus forMicrochemical Analysis3. Tolerances3.1 The following commercial length tolerance shall beadhered to, unless otherwise specified:Up to 10 mm 1 mm10 to 100 mm 2 mm100 to 200 mm 3 mm200 mm 4 mm4. Digestion Flasks4.1 Digestion flasks of three types shall confor
5、m to therequirements prescribed in Table 1 and Fig. 1, Fig. 2, and Fig.3. The flasks shall be made of shock-resistant glass with linearcoefficient of expansion not greater than 33.5 107cm/cmC.NOTE 2The weighing tubes described in Specification E124 Figs.1214 are recommended for introducing solid sam
6、ples into the microKjeldahl digestion flasks. Combustion boats, Fig. 1 and Fig. 2 ofSpecification E124, are recommended for use with waxy and nonvolatileliquid samples.5. Digestion Rack5.1 The micro Kjeldahl digestion rack shall be portable andshall consist of flask heaters (either gas or electric),
7、 a flasksupport, and a fume duct. The rack shall be supplied with a heatdeflector mounted under the burners to prevent overheating ofthe bench top.5.1.1 HeatersThe source of heat may be either electric orgas. In operation, each heater shall supply sufficient heat to a30-mL flask to cause 15 mL of wa
8、ter at 25C to come to arolling boil in not less than 2 or more than 3 min.Adevice shallbe provided for regulating the amount of heat supplied to theflask so that these conditions can be met. The amount of heatsupplied to the flasks also shall be so adjustable that low-temperature digestions are poss
9、ible. Switches and controlsshall be conveniently located and shall remain cool enough tohandle even after long periods of operation.NOTE 3Boiling chips shall be added when testing the heaters tominimize superheating, and the burners and rack shall be at equilibriumtemperature.5.1.2 Flask SupportThe
10、support on which the bulbs of theflasks rest shall shield the necks of the flasks from excessiveheating during digestion and shall be provided with circularopenings not exceeding 26 mm in diameter, centered over eachheater.5.1.3 Fume DuctThe fume duct shall provide means foradequately removing the f
11、umes evolved during the digestionand shall support the necks of the flasks at an angle greater than35 to the horizontal. Fume ducts meeting these specificationsare shown in Fig. 4 and Fig. 5. The fume duct illustrated in Fig.4 is supported and held in place by suitable clamps mounted ateither end of
12、 the digestion rack. The fume duct in Fig. 5 restsupon a circular support plate and is held in place by springsfrom the plate to the four glass hooks. The concave centerpermits clearance for the nut which fastens the support plate tothe center support post.6. One-Piece Distillation Apparatus6.1 The
13、one-piece model distillation apparatus shall con-form to the requirements of Fig. 6. The steam-generator vesselillustrated in Fig. 7 and the immersion heater in Fig. 8 are1This specification is under the jurisdiction of ASTM Committee E41 onLaboratory Apparatus and is the direct responsibility of Su
14、bcommitteeE41.01Laboratory Ware and Supplies.Current edition approved Jan. 1, 2017. Published February 2017. Originallyapproved in 1959. Last previous edition approved in 2011 as E147 61 (2011).DOI: 10.1520/E0147-61R17.2Committee on Microchemical Apparatus, “Recommended Specification forMicrochemica
15、lApparatus, Micro Kjeldahl Nitrogen,” Analytical Chemistry, Vol 23,1951, p. 523.3For 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
16、onthe ASTM website.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 theD
17、evelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1recommended for use with this apparatus, although any othersuitable combination may be substituted.6.2 The steam-generator vessel, Fig. 7, is a wide-m
18、outhedcommercially available resin reaction kettle. The interchange-able cover, with flat-ground rim and four ground-glasstubulations, is held in place with a suitable clamp. Thedistillation unit is connected to the center tubulation. Two ofthe outer three tubulations are used for the leads of theim
19、mersion-heater assembly, Fig. 8. The remaining tubulation isused for adding water to the kettle.6.3 The rate of steam generation may be controlled by a7.5-A variable transformer. The immersion heater shall be ofthe type that does not burn out when not immersed.NOTE 4Several methods of cleaning can b
20、e used. The followingmethod has been found satisfactory, particularly when boiling chips areemployed in the digestion: Turn off the steam generator while bothstopcocks are closed. The reduced pressure in the generator, brought aboutby cooling, causes the alkaline mixture in the distillation flask to
21、 besucked into the outer jacket. Open both stopcocks to drain off the liquid.Then, while steam is being generated and with both stopcocks closed, fillthe sample inlet funnel with water and immerse the tip of the condenserin about 100 mLof water contained in a beaker. Stop the steam generation,and op
22、en the stopcock of the funnel slowly, closing it before all the waterhas drained into the apparatus. Reduced pressure causes water to besucked from the beaker into the apparatus, thereby washing it. Open thestopcock in the drainage tube to empty the liquid that has collected in theouter jacket. If n
23、ecessary, start the steam generator again, and repeat therinsing procedure.7. Pregl Type (Parnas-Wagner) Distillation Apparatus7.1 The Pregl (Parnas-Wagner) type apparatus shall con-form to the requirements of Fig. 9, Fig. 10, and Fig. 11. Thesteam-generator vessel illustrated in Fig. 7 and the imme
24、rsionheater in Fig. 8 are recommended for use with this apparatus,although any other suitable combination may be substituted.TABLE 1 Digestion FlasksCapacity, mL Figure Use10 1 with digests of 1 mL or less30 2 with digests of 1 to 4 mL30 (Soltys) 3 with digests of 1 to 4 mL whendanger of spattering
25、isgreat.FIG. 1 10-mL Kjeldahl FlaskFIG. 2 30-mL Kjeldahl FlaskFIG. 3 30-mL (Soltys) Kjeldahl FlaskE147 61 (2017)2FIG. 4 Manifold for Micro Kjeldahl Digestion RackFIG. 5 Manifold for Micro Kjeldahl Digestion Rack (Circular Type)E147 61 (2017)3FIG. 6 Kjeldahl Distillation Apparatus, One-Piece ModelE14
26、7 61 (2017)4FIG. 7 Steam Generator Vessel, 2000-mL CapacityFIG. 8 Immersion Heater Assembly and Mounting PlatesE147 61 (2017)5FIG. 9 Steam Tube, Steam Trap, and Connecting TubeFIG. 10 Distillation Flask and Filling FunnelE147 61 (2017)6ASTM International takes no position respecting the validity of
27、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 any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to r
28、evision at any time by the responsible technical committee 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. Yo
29、ur comments will receive careful consideration at a meeting 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 cop
30、yrighted 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). 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:/ 11 Condenser Tube, Condenser Jacker (West Type), and Drain.E147 61 (2017)7
