ELISA-based quantification of cibacron blue F3GA used as ligand in affinity chromatography

The development of an enzyme-linked immunosorbent assay (ELISA) for Cibacron Blue F3GA is reported. It quantifies a trace amount of blue dye used as an affinity chromatography ligand, rendering possible the measurement of traces of leached dye. Polyclonal antibodies were prepared after conjugation on the dye on KLH and injection into rabbits. The ELISA test was based on the competitive inhibition between a hemoglobin-dye complex adsorbed on the wells of a titration microplate and a free dye. The sensitivity of the assay was about 1000 times higher than a classical spectrophotometric assay and was modulated by some chemical substituents to the dye. The described ELISA assay was also successfully applied to the quantification of dye traces in the presence of human albumin.