Investigation of high-speed gas chromatography using synchronized dual-valve injection and resistively heated temperature programming.
High-speed temperature programming is implemented via the direct resistive heating of the separation column (2.3m MXT-5 Silicosteel column with a 180 microm I.D. and a 0.4 microm 5% phenyl/95% dimethyl polysiloxane film). Resistive temperature programming was coupled with synchronized dual-valve injection (with an injection pulse width of 2 ms), producing a complete high-speed gas chromatography (GC) system. A comparison of isothermal and temperature programmed separations of seven n-alkanes (C(6) and C(8)-C(13)) shows a substantial improvement of peak width and peak capacity with temperature programming. The system was further implemented in separations of a mixture of analytes from various chemical classes. Separations of the n-alkane mixture using three different temperature programming rates are reported. A temperature programming rate as high as 240 degrees C/s is demonstrated. The method for determination of temperature programming rate, based on isothermal data, is discussed. The high-speed resistive column heating temperature programming resulted in highly reproducible separations. The highest rate of temperature programming (240 degrees C/s) resulted in retention time and peak width RSD, on average, of 0.5 and 1.4%, respectively, for the n-alkane mixture. This high level of precision was achieved with peak widths-at-half-height ranging from 13 to 36 ms, and retention times ranging from 147 to 444 ms (for n-hexane to n-tridecane).
Reid
Vanessa R
VR
Department of Chemistry, Box 351700, University of Washington, Seattle, WA 98195-1700, USA.
McBrady
Adam D
AD
Synovec
Robert E
RE
D000473:Alkanes / Q000032:analysis*; D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods*; D006586:Hexanes / Q000032:analysis; D009795:Octanes / Q000032:analysis; D015203:Reproducibility of Results; D013696:Temperature
D000473:Alkanes; D006586:Hexanes; D009795:Octanes; C026385:n-hexane; C094074:tridecane; C017573:nonane; C026728:octane