The AEC coloring system consists of two items: a concentrated AEC stock solution and five substrate buffer capsules. The contents of one capsule should be dissolved in 100 ml 30% ethanol. After complete dissolution, 20 ml of this buffer is thoroughly mixed with 1320 µl AEC stock solution (toxic, use fume hood). After mixing, the solution should be clear. This amount is sufficient for two ELISPOT plates (192 determinations). Once prepared, the solution is stable for 30 minutes at room temperature or for 6 months at -20ºC. The system provides an effective substrate for the streptavidin-HRP conjugate (CT353) generating red-colored spots on PVDF membranes. Upon ordering, you will receive one vial AEC stock solution (7 ml, to be stored at -20ºC upon arrival) and five substrate buffer capsules for 960 determinations.