ASTM_E_1140_-_95_2010e1.pdf

Designation:E114095(Reapproved 2010)1Standard Practice forTesting Nitrogen/Phosphorus Thermionic IonizationDetectors for Use In Gas Chromatography1This standard is issued under the fixed designation E1140;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.1NOTEEditorial corrections were made to Footnote 3 in November 2010.1.Scope1.1 This practice covers testing the performance of anitrogen/phosphorus thermionic ionization detector(NPD)used as the detection component of a gas chromatographicsystem.1.2 This practice applies to an NPD that employs a heatedalkali metal compound and emits an electrical charge from thatsolid surface.1.3 This practice addresses the operation and performanceof the NPD independently of the chromatographic column.However,the performance is specified in terms that the analystcan use to predict overall system performance when thedetector is coupled to the column and other chromatographiccomponents.1.4 For general chromatographic procedures,Practice E260should be followed except where specific changes are recom-mended in this practice for the use of a nitrogen/phosphorus(N/P)thermionic detector.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specific safetyinformation,see Section 5,Hazards.2.Referenced Documents2.1 ASTM Standards:2E260 Practice for Packed Column Gas ChromatographyE355 Practice for Gas Chromatography Terms and Relation-ships2.2 CGA Standards:3CGA P-1 Safe Handling of Compressed Gases in ContainersCGA G-5.4Standard for Hydrogen Piping Systems atConsumer LocationsCGA P-9 The Inert Gases:Argon,Nitrogen and HeliumCGA V-7 Standard Method of Determining Cylinder ValveOutlet Connections for Industrial Gas MixturesCGA P-12 Safe Handling of Cryogenic LiquidsHB-3 Handbook of Compressed Gases3.Terminology3.1 Definitions:3.1.1 For definitions of gas chromatography and its variousterms,see Practice E355.3.2 Definitions of Terms Specific to This Standard:3.2.1 driftthe average slope of the noise envelope ex-pressed in amps/h as measured over12h.3.2.2 linear rangerange of mass flow rates of nitrogen orphosphorus in the carrier gas,over which the sensitivity of thedetector is constant to within 5%as determined from thelinearity plot.3.2.3 minimum detectabilitythe mass flow rate of nitrogenor phosphorus in the carrier gas that gives a detector signalequal to twice the noise level.3.2.4 noise(short term)the amplitude,expressed inamperes,of the baseline envelope that includes all randomvariations of the detector signal of a frequency greater than onecycle per minute.3.2.5 selectivitythe ratio of the response per gram ofnitrogen or phosphorus in the test substance to the response pergram of carbon in octadecane.4.Significance and Use4.1 Although it is possible to observe and measure each ofthe several characteristics of a detector under different andunique conditions,it is the intent of this practice that a1This practice is under the jurisdiction of ASTM Committee E13 on MolecularSpectroscopy and Separation Science and is the direct responsibility of Subcom-mittee E13.19 on Separation Science.Current edition approved Nov.1,2010.Published December 2010.Originallyapproved in 1986.Last previous edition approved in 2005 as E1140 95(2005).DOI:10.1520/E1140-95R10E01.2For 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.3Available from Compressed Gas Association(CGA),4221 Walney Rd.,5thFloor,Chantilly,VA 20151-2923,http:/.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 complete set of detector specifications be obtained at the sameoperating conditions,including geometry,flow rates,andtemperatures.To specify a detectors capability completely,itsperformance should be measured at several sets of conditionswithin the useful range of the detector.The terms and testsdescribed in this practice are sufficiently general so that theymay be used under any chosen conditions.4.2 Linearity and speed of response of the recorder shouldbe such that it does not distort or otherwise interfere with theperformance of the detector.Effective recorder response shouldbe sufficiently fast so that its effect on the sensitivity ofmeasurement is negligible.If additional amplifiers are usedbetween the detector and the final readout device,theircharacteristics should first be established.5.Hazards5.1 Gas Handling Safety