STOPT Reagent – Liquid, Clear, colorless liquid

Description: Stop and stabilize TMB microwell substrate reactions.
Stop Solution for TMB Substrates (STOPT) is a proprietary acidic formulation used to stop TMB microwell substrate reactions. It is suitable for all endpoint ELISAs using a tetramethylbenzidine (TMB) substrate reaction for color development.

TMB substrates are oxidized by peroxidase enzymes to yield a soluble blue-green reaction product. In endpoint assays, the reaction can be stopped by adding equal volumes of Stop Solution for TMB Substrates. Addition of STOPT changes the chromagen color from blue-green to yellow, where it can be read at 450 nm, and concurrently stabilizes the yellow TMB product for one hour. Stopping the reaction will increase the sample absorbance value up to 3-fold. To avoid overdeveloping the TMB substrate reaction, the blue-green reaction product should be periodically monitored on an ELISA plate reader using 620-650 nm absorbance filter settings. When OD values reach approximately 0.7 units, the reaction should be stopped with STOPT.

For best results, the absorbance should be monitored and read before values exceed 2.5 OD units. If the yellow reaction product yields OD values above 2.5 units, it is recommended to dilute the antibodies/conjugates or shorten the incubation period.

Stop Solution for TMB Substrates is ready to use at 1X. Stop the reaction by adding an equal volume of STOPT to the substrate in every well of the plate.

Small volumes of STOPT reagent vial(s) may occasionally become entrapped in the seal of the product vial during shipment and storage. If necessary, briefly centrifuge the vial on a tabletop centrifuge to dislodge any liquid in the container`s cap. Certain products may require to ship with dry ice and additional dry ice fee may apply.

MBS258078 is a reagent targeting STOPT. Also known as Stop Solution for TMB Substrates (Liquid).