ASTM_E_191_-_64_2011.pdf

Designation:E19164(Reapproved 2011)Standard Specification forApparatus For Microdetermination of Carbon andHydrogen in Organic and Organo-Metallic Compounds1This standard is issued under the fixed designation E191;the number immediately following the 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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This specification covers apparatus and basic equipmentfor the determination of carbon and hydrogen in organic andorganometallic compounds along the lines of the conventionalmethod of Pregl,but with modifications more in line withmodern practice.Owing to the diversity of apparatus by whichcorrect results can be obtained,this specification is intended toindicate what is acceptable rather than what is mandatory.NOTE1Specifications for several items subsequently listed weredeveloped by the Committee for the Standardization of MicrochemicalApparatus,Division of Analytical Chemistry,American Chemical Soci-ety.21.2 The values stated in inch-pound units are to be regardedas the standard.The metric equivalents of inch-pound unitsmay be approximate.2.Referenced Documents2.1 ASTM Standards:3E124 Specification for Weighing and Drying Apparatus forMicrochemical AnalysisE148 Specification for Apparatus for Microdetermination ofNitrogen by the Dumas Method(Withdrawn 1987)43.Oxygen Supply3.1 Any cylinder or other suitable source of oxygen free ofhydrogen and organic impurities may be used.Oxygen pre-pared from liquid air is satisfactory.4.Pressure Regulator4.1 The pressure regulator,shown in Fig.1 and Fig.2,5consisting of a bell and inlet tube submerged in a suitableconfining liquid,shall be used to supply air or oxygen,or both,at constant pressure to the combustion system.Substitution ofa fine gas-control valve and flowmeter for the pressure regu-lator is optional.5.Drying and Purifying Tube25.1 The conventional bubble-container U-tube shown inFig.3 shall be used for drying and purifying the entering air oroxygen,or both.6.Flowmeter6.1 The rate of gas flow shall be determined by the bubblecounter of the bubble-counter U-tube,or by a more accurateflow-meter,such as the floating ball-in-column.67.Combustion Unit7.1 The combustion unit shall consist of a long furnace,asample furnace,a constant-temperature heating mortar,acombustion tube,and a combustion-tube closure.7.1.1 Long Furnace:7.1.1.1 The long furnace shall have a maximum over-alllength of 8 in.(203 mm)with the wall thickness at the ends notto exceed14in.(6 mm).The furnace shall accommodatecombustion tubes up to 13 mm in outside diameter.Electricheating elements shall be easily replaceable.The furnace shallbe mounted firmly on a substantial support.7.1.1.2 The furnace shall be capable of continuous operationat temperatures up to 900C as measured inside the combustiontube at the middle of the furnace.The temperature drop fromthe center to points 1 in.(25 mm)and 134in.(45 mm)fromeither end shall not exceed 15 and 7%,respectively,based1This specification is under the jurisdiction of ASTM Committee E41 onLaboratory Apparatus and is the direct responsibility of Subcommittee E41.01 onApparatus.Current edition approved Oct.1,2011.Published November 2011.Originallyapproved in 1962.Discontinued in 1988 and reinstated in 1989.Last previousedition approved in 2005 as E191 64(2005).DOI:10.1520/E0191-64R11.2Committee for the Standardization of Microchemical Apparatus.Division ofAnalytical Chemistry,American Chemistry Society,1949 Report on RecommendedSpecifications for Microchemical Apparatus,Carbon-Hydrogen,Dumas Nitrogen,Sulfur,and Halogen,Analytical Chemistry Vol 21,p.1555(1949).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 onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.5Furter,M.F.,and Steyermark,A.,“Pressure Regulator for Use in Microdeter-mination of Carbon and Hydrogen,”Analytical Chemistry,Vol 20,1948,p.257.6Kuck,J.A.,and Altieri,P.L.,“Spherical Ground-Glass Joints vs.RubberTubing Connectors on the C and HAbsorption Train,”Mikrochimica Acta,1956,p.1556.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 upon the temperature in the middle of the furnace.7Meansshall be provided for varying the temperature.7.1.1.3 The furnace shall be equipped with some device forindicating the temperature at the middle of the furnace.7.1.2 Sample Furnace,Traveling Type(Note 2):7.1.2.1 The sample furnace shall have an over-all length notless than 212in.(64 mm)nor more than 4 in.(102 mm)withwall thickness at the ends not t