Enzyme-linked immunosorbent assays based on peroxidase labels and enzyme-amplified lanthanide luminescence detection

The enzyme-amplified lanthanide luminescence (EALL) detection is developed and applied for the determination of peroxidase as marker in enzyme-linked immunosorbent assays (ELISA). The detection scheme is based on the peroxida se catalysed dimerisation of 4-hydroxyphenylpropionic acid (pHPPA) and the subsequent formation of a ternary complex with Tb(iii)EDTA. Quantum yields and fluorescence lifetimes of the luminescent species are presented to give an estimate of the potential of this procedure. Two different ELISA were p erformed with the EALL detection scheme. For the first, a model ELISA for t he determination of goat anti-rabbit IgG, a limit of determination of 3 mug dm(-3) (2 fmol) of the antibody could be achieved. As second model assay, a commercial ELISA kit was successfully validated for the new detection sch eme. Photometric and EALL detection were in good agreement for the determin ation of human anti-gliadin IgA in serum.