COMPARISON OF THE EFFICIENCY OF PACKED AND CAPILLARY COLUMNS TO BE USED IN SUPERCRITICAL FLUID CHROMATOGRAPHY FOR THE ANALYSIS OF NONVOLATILE COMPOUNDS

A mixture of two amides has been used as a probe to achieve van Deemter plots for both packed and capillary columns employing as nearly as possible the same stationary phase, 100% CO2 as the mobile phase and isothermal/isoconfertic conditions. Linear velocity was varied via the use of various flow restrictor inner diameters. Chromatographic operating conditions were not optimized, but were those that have become routine in many laboratories. Plots of both capacity factor vs density and resolution vs density at different temperatures are presented for each column. Based on this study, various conclusions are drawn regarding the optimum performance of each column under different operating conditions. Direct injection with the capillary column yielded different optimum chromatographic parameters relative to split injection wherein the column was not overloaded. © 1990 Friedr. Vieweg & Sohn Verlagsgesellschaft mbH.