TMB Membrane Substrate is a ready to use solution. It contains 3,3’,5,5’-tetramethyl-benzidine in a mildly acidic buffer in a one bottle format. TMB Membrane Substrate develops an insoluble, permanent dark blue reaction in the presence of peroxidase. The substrate is intended for western blot, dot blots, and line assays and offers comparable performance and sensitivity to some chemiluminescent substrates. This substrate is not recommended for microwell or immunohistochemical applications. Stable for 2 years, from the date of manufacture, when stored at room temperature (15 to 25C) or 48 months when stored at 2-8C.