pIMAGO-biotin enables detection and quantitation of phosphorylated proteins immobilized on a microplate using streptavidin-linked fluorophore at 800 nm absorbance for detection. The kits include pIMAGO-biotin reagent, streptavidin-linked Fluor 800 detection reagent, blocking buffer, pIMAGO buffer, high-binding 96-well adsorption plates and a control phosphoprotein.