Description_x000D_ Application_x000D_ o-Phenylenediamine is a peroxidase substrate suitable for use in ELISA procedures. The substrate produces a soluble end product that is orange-brown in color and can be read spectrophotometrically at 450 nm. The OPD reaction may be stopped with 3 N HCl or 3 M H2SO4 and read at 492 nm._x000D_ Packaging_x000D_ 1 kg in glass bottle_x000D_ 10, 25, 50, 100 g in glass bottle_x000D_ Caution_x000D_ May darken in storage.