TMB (3, 3', 5, 5'-tetramethylbenzidine) is a chromogenic substrate for Horseradish Peroxidase (HRP). TMB produces a deep blue color during the enzymatic degradation of hydrogen peroxide by HRP, and the addition of a stop solution gives a clear yellow color that absorbs at 450nm. This substrate gives higher signal and has a higher sensitivity in ELISA than OPD (ortho-phenylenediamine dichloride).

TMB X-tra characteristics are:

• High sensitivity
• Stable and robust
• Aqueous based – no organic solvents (REACH Annex XVII compliant)
• Low lot-to-lot variation
• Suitable for use in electrochemical assays

For traceable pipetting, we recommend using pink colored TMB X-tra Prestained (cat. no. 4810). The pink indicator disappears after addition of the stop solution.

The product is available in bulk quantities and as customized solutions.