Question

Why does plate height depend on linear velocity, not volume flow rate?

Short answer

The solution is

the longitudinal diffusion ($\frac{\mathrm{B}}{{\mathrm{u}}_{\mathrm{x}}}$) is inversely proportional to the duration the solute spends on the column (${\mathrm{u}}_{\mathrm{x}}$).

Step-by-step solution

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We'll explain why plate height is affected by linear velocity but not by volume flow rate in this work.

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Volume flow rate

- for example,$1\frac{\mathrm{mL}}{\min }$ ; indicates how many mL of solvent pass through the column per minute.

Flow rate that is linear.

- For example,$1\frac{\mathrm{cm}}{\min }$ tells us how many cm the solvent travels per minute.

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As a result, linear flow rate defines how complete the two-phase equilibrium is:

- the van Deemter equation is used to calculate the value of equilibration time (mass transfer).

- furthermore, the longitudinal diffusion ($\frac{\mathrm{B}}{{\mathrm{u}}_{\mathrm{x}}}$)is inversely proportional to the duration the solute spends on the column (${\mathrm{u}}_{\mathrm{x}}$).