| Abstract: | The negative effect of the liquid stationary phase film thickness on the column efficiency is strongest for peaks with retention factors, k, in the vicinity of k = 0.3–0.4 and rapidly diminishes with the departure of k from that region. Additionally, at the high pressure drop required for fast analysis of complex mixtures, the negative effect of the same film thickness diminishes with the increase in column length, regardless of the k values. In practice, it is recommended to ignore the film thickness and optimize the columns as thin film ones regardless of their actual film thickness. Accounting for the film thickness results only in a modest improvement in the resolution for a few affected peaks – those with k = 0.3–0.4. However, this improvement comes at the cost of a substantial increase in analysis time, and should be used only as the action of the last resort. |
