Plate Theory and Extensions - Temperature Changes During the Passage of a Solute Through a Theoretical Plate in Gas Chromatography > Page 81
Condition (4) assumes that the heat convected from the plate by the flow of gas through it is negligible compared with that conducted from the plate to the surroundings. This assumption is reasonable for a GC system but will certainly not be true when the mobile phase is a liquid.
As the plate concept is to be employed the volume flow will be measured in plate volumes (v), i.e.,
Consider the heat balance of the plate,
Heat Capacity of Plate x Rise in Temperature =
Heat Evolved in Plate (HC) – Heat Conducted from Plate (GC)
Consider the heat balance over a time (dt) during which there is a flow of mobile phase (dv) and a temperature change (dq), then