High speed chromatography

Column temperature affects the relative retention of different compounds and elevated temperature permits high-speed chromatography to be conducted.25 Figure 25-28 suggests a systematic procedure for method development in which solvent composition and temperature are the two independent variables.1 For elevated temperature operation, pH should be below 6 to retard dissolution of silica. Alternatively, zirconia-based stationary phases work up to at least 200°C. 

Detector Time Constant - (D ) - The overall time constant of the sensor and electronics and is usually given in milliseconds. It is mainly of interest in high speed chromatography. 

High-speed chromatography combines column selectivity and special selectivity adjustment techniques with conventional 2DGC to improve the speed of analysis in what is essentially a rapid, heart-cutting technique. " Rapid chromatography requires cryofocusing of analytes in... 

A comprehensive GC X 2GC technique with differential flow modulation has been developed for rapid analysis of VOCs. " In comprehensive GC X 2GC, two secondary columns of different polarities are used, requiring a GC with two detectors to monitor the column effluents. The flow-switching device is a modification of the unit developed by Sacks and Akard " for high-speed chromatography. The flow of carrier gas to the columns is controlled by a three-port solenoid valve placed outside the GC oven and not in the sample flowpath. Parallel and serially positioned tee unions control the flows of carrier and auxiliary gases and interface the primary column effluent to the secondary columns. Bueno and Seeley " used a 5.0 m X 0.25 mm i.d. capillary column with a... 

R. Grix, R. E. Tecklenburg, Jr., J. T. Watson, J. F. Holland, G. E. Yefchak, B. D. Gardner, J. Allison, C. G. Enke, and H. WoUnik, A time-of-flight mass spectrometer for high-speed Chromatography, Proc. of the 39th ASMS Conf. Mass Spectrometry and Allied Topics, Nashville, TN, May 19-24, 1991. 

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