1. Solid phase extraction

1.1 Principle

Liquid-solid extraction is based on the distribution of compounds between the liquid phase (sample) and the solid phase (chosen adsorbent). To a first approximation, it is a process similar to elution chromatography, using the adsorbent as the stationary phase: if the solute has a strong affinity for the adsorbent, it remains totally bound to it during percolation of the aqueous sample (figure 1 ). The solute is then desorbed by a small volume of eluting solvent.

Knowledge of the retention mechanisms involved in liquid chromatography can therefore be directly transposed to this extraction technique, facilitating method development.