Selected ion flow tube: Difference between revisions

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The '''selected ion flow tube''', '''SIFT''', technique is a fast flow tube method for the study of the reactions of [[ion|ions]] ([[ion]] chemistry over a 20-year period has been crucial to the advancement and understanding of these interesting topics. Recently it has been developed as a very sensitive analytical technique '''SIFT-MS [[Selected Ion Flow Tube Mass Spectrometry]]''' for the quantification of trace gases in air and in human breath down to the ppb level in real time using [[Chemical Ionization]].
{{Final
 
|acronym=([[SIFT]])
===Instrumentation===
|def=Device in which ''[[m/z]]'' selected ions are entrained in an inert carrier gas and subsequently undergo [[ion/molecule reaction]]s with molecules introduced into the gas flow.
 
|rel=[[drift tube]]
'''The SIFT apparatus'''
|ref=N. G. Adams, D. Smith. Int. J. Mass Spectrom. Ion Phys. 21, 349 (1976). (http://dx.doi.org/10.1016/0020-7381(76)80133-7 )
 
}}
In the SIFT apparatus the ions are created in an [[ion source]] which is external to the flow tube. The ions are then extracted from the ion source, selected according to their mass-to-charge ratio using a [[quadrupole]] mass filter and injected into a flowing carrier gas (usually helium at a pressure of 0.5 Torr) via a small orifice ( ~1 mm diameter).
 
The carrier gas is inhibited from entering the quadrupole mass filter chamber by injecting it into the flow tube through a Venturi-type inlet at near-supersonic velocity in a direction away from the orifice. In this way a swarm of a single ion species thermalised at the same temperature as the carrier gas are convected along the flow tube ( ~1 m long), sampled by a downstream pinhole orifice, mass analysed and counted by a differentially-pumped quadrupole [[mass spectrometer]] system.  
 
 
== Related Terms ==
 
[[Drift Tube]]
 
 
== External Links ==
 
[http://www.jh-inst.cas.cz/~spanel/sift.
 
[http://www.chem.yorku.ca/profs/bohme/research/et__MAIN.html York University]
 
[[Category:Ionization]]
[[Category:Ionization]]
[[Category:Reactions]]
[[Category:Reactions]]

Latest revision as of 13:16, 8 January 2014

IUPAC RECOMMENDATIONS 2013
Selected ion flow tube (SIFT)
Device in which m/z selected ions are entrained in an inert carrier gas and subsequently undergo ion/molecule reactions with molecules introduced into the gas flow.
Related Term(s): drift tube
Reference(s):

N. G. Adams, D. Smith. Int. J. Mass Spectrom. Ion Phys. 21, 349 (1976). (http://dx.doi.org/10.1016/0020-7381(76)80133-7 )

From Definitions of Terms Relating to Mass Spectrometry (IUPAC Recommendations 2013); DOI: 10.1351/PAC-REC-06-04-06 © IUPAC 2013.

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