This product is not recommended for enzyme-linked immunosorbent assay (ELISA) applications due to the resulting insoluble, dark-blue reaction product. This solution is intended for membrane-based applications, such as Western blotting. For enzyme-linked immunosorbent assay applications, use a 3,3',5,5'-tetramethylbenzidine (TMB) substrate that produces a soluble reaction product.
Please see the link below to review additional information available in the product datasheet:
https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/153/539/t0565-pis-ms.pdf
Please see the following link to review product T0440, a soluble TMB substrate suitable for use in ELISA:
https://www.sigmaaldrich.com/product/sigma/t0440

