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T0440 Sigma

3,3′,5,5′-Tetramethylbenzidine (TMB) Liquid Substrate System for ELISA

peroxidase substrate

Synonym: TMB



Frequently Asked Questions

Frequently Asked Questions are available for this Product.


TMB is a substrate for horseradish peroxidase. Develops a soluble blue reaction product that may be read at 370 or 655 nm. For endpoint assays the reaction may be stopped with acid, forming a yellow reaction product that may be read at 450 nm. Recommended for ELISA (microwell) procedures, not recommended for membrane applications.


Stable at least one year at 2-8 °C.

Physical form


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LC-MS Grade Solvents and Reagents

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Safety Information

NONH for all modes of transport

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis. These documents are located on the product detail page under Useful Links & Tools. Click on the following link to search for a Certificate of Analysis. Please click the following link to see the details on our Product Dating Information.
How do I get lot-specific information or a Certificate of Analysis?
A Certificate of Analysis is available by lot number and can be obtained through our Advanced Search Option: http://www.sigmaaldrich.com/catalog/AdvancedSearchPage.do
Do I need to add hydrogen peroxide to Product T0440, 3, 3′,5,5′-Tetramethylbenzidine (TMB) Liquid Substrate System for ELISA?
No hydrogen peroxide should be added to product T0440. The product, which contains  a peroxidase substrate,  already contains hydrogen peroxide.  This solution is ready to use for ELISA assays.  Instructions for use can be found on our data sheet at our website. Click on the link: http://www.sigmaaldrich.com/sigma/datasheet/t0440dat.pdf
What is the concentration of the TMB and what is the solvent in Product T0440, 3, 3′,5,5′-Tetramethylbenzidine (TMB) Liquid Substrate System for ELISA?
The concentration of TMB in this formulation and the identity of the solvent are considered proprietary information. The product is a ready-to-use peroxidase substrate containing TMB in a mildly acidic buffer. Instructions for use can be found on our data sheet at our webite. Click on the link: http://www.sigmaaldrich.com/etc/medialib/docs/Sigma/Datasheet/5/t0440dat.pdf
Do I need to dilute Product T0440, 3, 3′,5,5′-Tetramethylbenzidine (TMB) Liquid Substrate System for ELISA?
No, the product should not be diluted.. The product is ready-to-use for ELISA applications. If the intensity of the reaction needs to be reduced, it is recommended that the antibodies or  conjugates be diluted. Usage information  is described on our data sheet at our website.  Click on the link:  http://www.sigmaaldrich.com/sigma/datasheet/t0440dat.pdf
What is the difference between products T0440, 3, 3′,5,5′-Tetramethylbenzidine (TMB) Liquid Substrate System for ELISA,  and T8665, 3,3′,5,5′-Tetramethylbenzidine (TMB) Liquid Substrate System?
Both products are comparable and either one can be used in ELISA procedures. The formulations which are proprietary may have some slight differences.
How do I find price and availability?
There are several ways to find pricing and availability for our products.  Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers. 
What is the Department of Transportation shipping information for this product?
Transportation information can be found in Section 14 of the product's (M)SDS. To access the shipping information for this material, use the link on the product detail page for the product, or search here. 
My question is not addressed here, how can I contact Technical Service for assistance?
Use the option to the right to "Ask a Question" by email of a Technical Service Scientist.
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