Editing Plasma afterglow (section)

=== Flowing afterglow  ===

A flowing afterglow is an [[ion source]] that is used to create ions in a flow of [[inert gas]], typically [[helium]] or [[argon]].<ref name="FergusonFehsenfeld1969">{{Cite book|last1=Ferguson|first1=E. E.|last2=Fehsenfeld|first2=F. C.|last3=Schmeltekopf|first3=A. L.|title=Ion-Molecule Reaction Rates Measured in a Discharge Afterglow|volume=80|date=1969|pages=83–91|issn=0065-2393|doi=10.1021/ba-1969-0080.ch006|series=Advances in Chemistry|isbn=978-0-8412-0081-4}}</ref><ref name="Ferguson1992">{{cite journal|last1=Ferguson|first1=Eldon E.|title=A Personal history of the early development of the flowing afterglow technique for ion-molecule reaction studies|journal=Journal of the American Society for Mass Spectrometry|volume=3|issue=5|date=1992|pages=479–486|issn=1044-0305|doi=10.1016/1044-0305(92)85024-E|pmid=24234490|url=https://zenodo.org/record/1258658|type=Submitted manuscript|doi-access=free}}</ref><ref name="Bierbaum2014">{{cite journal|last1=Bierbaum|first1=Veronica M.|title=Go with the flow: Fifty years of innovation and ion chemistry using the flowing afterglow|journal=International Journal of Mass Spectrometry|date=2014|issn=1387-3806|doi=10.1016/j.ijms.2014.07.021|bibcode = 2015IJMSp.377..456B|volume=377|pages=456–466}}</ref> Flowing afterglow ion sources usually consist of a dielectric discharge that gases are channeled through to be excited and thus made into plasma. Flowing afterglow ion sources can be coupled with a [[Selected-ion flow-tube mass spectrometry|selected-ion flow-tube]] for selection of reactant ions.<ref name="Squires1992">{{cite journal|last1=Squires|first1=Robert R.|title=Advances in flowing afterglow and selected-ion flow tube techniques|journal=International Journal of Mass Spectrometry and Ion Processes|volume=118-119|date=1992|pages=503–518|issn=0168-1176|doi=10.1016/0168-1176(92)85074-A|bibcode = 1992IJMSI.118..503S }}</ref> When this ion source is coupled with mass spectrometry it is referred to as flowing afterglow mass spectrometry.

'''Flowing-afterglow mass spectrometry''' uses a flowing afterglow to create protonated water cluster [[ions]] in a helium or argon carrier gas in a flow tube that react with sample molecules that are measured by a mass spectrometer downstream.<ref name="SmithŠpaněl2005">{{cite journal|last1=Smith|first1=David|last2=Španěl|first2=Patrik|title=Selected ion flow tube mass spectrometry (SIFT-MS) for on-line trace gas analysis|journal=Mass Spectrometry Reviews|volume=24|issue=5|date=2005|pages=661–700|issn=0277-7037|doi=10.1002/mas.20033|pmid=15495143|bibcode=2005MSRv...24..661S}}</ref> These systems can be used for [[trace gas]] analysis. This works by keeping the initial ionization source spatially separated from the target [[analyte]] and channeling the afterglow of the initial ionization towards the analyte. Analytes are added downstream to create ion products. Ions  Detection of ions is usually accomplished using a [[mass spectrometer]] or by [[optical spectroscopy]].<ref name="JohnsenSkrzypkowski2003">{{Cite book|last2=Skrzypkowski|first2=M.|last3=Gougousi|first3=T.|last4=Rosati|first4=R.|last5=Golde|first5=M. F.|date=2003|pages=25–35|doi=10.1007/978-1-4615-0083-4_3|last1=Johnsen|first1=R.|title=Dissociative Recombination of Molecular Ions with Electrons |chapter=Optical Spectroscopy of Recombining Ions in Flowing Afterglow Plasmas |isbn=978-1-4613-4915-0}}</ref>