Document Detail


Band acceleration device for enhanced selectivity with tandem-column gas chromatography.
MedLine Citation:
PMID:  16130667     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
An electrically heated and air cooled metal sheath surrounding the first 50 cm of the second column in a series-coupled, capillary-column ensemble of a non-polar and a polar column is used to obtain enhanced isothermal separation of component pairs that are separated by the first column in the ensemble but co-elute from the ensemble by virtue of the different selectivity of the two columns. As the first of the two components passes into the second column, a current pulsed through the metal sheath rapidly heats the first 50 cm of the second column thus accelerating the band for the first component. Ensemble retention-time shifts of several seconds are easily obtained. The device is then rapidly cooled to quiescent oven temperature by a flow of pressured air through the space between the metal sheath and the fused silica capillary column and an additional flow through a larger, co-axial plastic tube. Both heating and cooling require only a few seconds. If substantial cooling of the device occurs before the band for the second component enters the device, the band experiences less thermally-induced acceleration with the result that the separation of the two targeted components is enhanced in the ensemble chromatogram with no significant change in the pattern of peaks for the other mixture components. If the device is cooled to a temperature below oven temperature before the arrival of the band for the second component, this band will be slowed, and further enhancement of separation is achieved in the ensemble chromatogram. A band trajectory model, based on retention factor versus temperature data for the two components in the two columns, is used to predict peak separation and to aid in the selection of temperature-pulse initiation times.
Authors:
Mark Libardoni; Megan McGuigan; Young J Yoo; Richard Sacks
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of chromatography. A     Volume:  1086     ISSN:  0021-9673     ISO Abbreviation:  J Chromatogr A     Publication Date:  2005 Sep 
Date Detail:
Created Date:  2005-08-31     Completed Date:  2005-10-04     Revised Date:  2009-01-15    
Medline Journal Info:
Nlm Unique ID:  9318488     Medline TA:  J Chromatogr A     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  151-9     Citation Subset:  IM    
Affiliation:
Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
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MeSH Terms
Descriptor/Qualifier:
Chromatography, Gas / instrumentation*
Sensitivity and Specificity
Temperature

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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