Backpressure indicator

Indicates the pressure drop across the column (in bar) at the given flow rate, eluent viscosity, and column geometry. In gradient mode, the backpressure indicator only shows "--". To see the backpressure, you must plot it by choosing "Plot backpressure" in the "Plot Options" control panel.

Calculation

The pressure drop across the column is calculated from the Darcy equation. See Thompson, J. D.; Carr, P. W. Anal. Chem. 2002, 74, 4150-4159.

where
ΔP = pressure drop across column
us = open tube flow velocity
η = eluent viscosity
L = column length
εe = interstitial porosity
dp = particle size

Remarks

For the purpose of this simulator, the pressure drop across the column is considered to be the only significant contributor to the backpressure. When adjusting the chromatographic conditions, be sure to check that the backpressure is within a reasonable range. Most HPLC instruments can reach a maximum pressure of 400 bar, while most UPLC instruments can reach a maximum pressure of 1000 bar.