Frontal affinity chromatography combined on-line with mass spectrometry: a tool for the binding study of different epidermal growth factor receptor inhibitors.

Frontal affinity chromatography (FAC) is a simple but powerful method to analyze molecular interactions between an analyte and an immobilized ligand by calculating the extent of retardation of the elution front. By combination of FAC with a PE-Mariner electrospray ionization mass spectrometry, a very efficient and straightforward procedure was developed herein for analyzing the binding properties of different inhibitors of the epidermal growth factor receptor (EGFR). In this study, a polyclonal antibody prepared with a known anti-EGFR inhibitor coupled with bovine serum albumin was adopted as the stationary phase in the FAC system. Using the antibody to mimic the receptor, other different anti-EGFR inhibitors as well as the small-molecule half-antigen itself were recognized directly from the crude extract of herb, which afforded us a novel promising approach for the efficient screening of lead compounds or drug candidates from natural resources.