Density gradients in packed columns

Autor: Steven R. Goates, Andrew W. Orton, Brent A. Horn, L. Robert Baker, Marisa A. Stark
Rok vydání: 2009
Předmět:
Zdroj: Journal of Chromatography A. 1216:5588-5593
ISSN: 0021-9673
DOI: 10.1016/j.chroma.2009.05.042
Popis: Density gradients in packed capillary columns operating under the extreme pressure drops typical for solvating gas chromatography were investigated by on-column spectroscopic measurements and compared to a theoretical model. Laser-induced fluorescence was used to follow the elution of various analytes, and Raman spectroscopy was used to measure the density of the mobile phase, each with respect to column position. Mobile phase linear velocity initially increases gradually, and then rises rapidly near the column outlet. High flow rates near the column outlet are offset by a loss of mobile phase solvating power which ultimately limits the speed of separation. These results represent an extreme case for illuminating factors affecting supercritical fluid separation techniques in general.
Databáze: OpenAIRE