Theory of fast capillary gas chromatography. Part 1: Column efficiency

Typically, fast GC requires high column pressure drop. Under that condition, known relations do not provide a complete description of dependence of [apparent] plate height, ĥ, on average velocity, u, of carrier gas. A complete descriptions for ĥ vs. u is derived and analyzed. It is shown that, under the high pressure drop, ĥ = B/u2 + C1 u2 + C2 u. This is substantially different from the Van Deemter equation ĥ = B/u + Cu for the low pressure drop. Analytical expressions for the minimum plate height and for the respective optimum u under the high pressure drop are derived and analyzed.