Fig. 1.

Frontal affinity chromatography (FAC) 1 a compound or mixture is continuously infused onto an affinity column (2). The column (backbone) material that is immobilized with target protein, such as a receptor, retains compounds with affinity. 3 detection of breakthrough of ligands with mass spectrometry (MS). 4a–7a snapshots of the chromatographic breakthrough process of the ligands at different time points during a FAC analysis. 4b–7b corresponding detection of breakthrough events with MS per ligand. At full breakthrough, the infused ligand concentration equals the eluted concentration