Use of the kinetic plot method to analyze commercial high-temperature liquid chromatography systems: II. Practically constrained performance comparison

Using a set of experimentally determined plate height data obtained on three commercial high-temperature HPLC supports, and evaluating their isocratic separation speed potential under the application of a set of instrumental constraints, a qualitative map of the practically achievable critical pair separation speed potential of high-temperature HPLC has been established. The obtained data show that the gain in separation speed is more strongly affected by the instrumental limitations in the high-temperature range than it is for the low temperatures. For the presently considered case of alkylbenzene separations, the potential gain in analysis time that can be obtained by going from T = 30 to 120 °C in the presence of a typical set of instrumental limitations nevertheless remains of the order of a factor of 2–4. The study also shows that improvements on the instrumentation side (increased detector frequency, pumping flow rate, smaller extra-column volumes, …) are indispensable to fully benefit from the high temperature advantages for all separations requiring less than 10,000 effective theoretical plates.