Column length is a structure-independent measure of solvent consumption in liquid chromatography

Column length (L) is a measure of solvent consumption in LC analysis. In its latter role, L is the specific solvent consumption - the void time (t_M) solvent consumption per unit of the column flow-area (A_F) which is the cross-sectional area of the column open space (external and internal pores). In t_anal-long LC analysis (isocratic or gradient), the solvent consumption (V_S) is V_S = A_FLt_anal /t_M regardless of flow rate (F) as long as all changes in column dimensions and operational parameters are translatable (in gradient analysis, the ratio of the gradient time (t_G) to t_M remains fixed).