4. Calibration curves

They can be plotted very simply by plotting the detector response as a function of the quantity or concentration injected. In ultraviolet, visible or fluorescence, due to Beer's law, all curves have a straight part at low concentrations. Then they curve more or less sharply before reaching a plateau, which indicates detector saturation. This applies to both TLC and forced-flow CP with elution. Strictly speaking, the area under the peak should be recorded, but the peak height may be more than sufficient in the case of well-resolved substances [19] .

Linearization of the calibration curve should be carried out by regression. Each solute has its own calibration curve.

• A relationship of the type y = Ax + B (with y detector response and x solute concentration)...