P9187 Sigma-Aldrich



Synonym: OPD Peroxidase Substrate

  •  NACRES NA.83




SIGMAFAST OPD (o-Phenylenediamine dihydrochloride) tablets have been developed for use as a soluble substrate for the detection of peroxidase activity in enzyme immunoassays (EIA). OPD is the EIA substrate of choice as it exhibits high sensitivity. EIA applications utilizing OPD may be read in timed assays or stopped with dilute acid solutions for delayed readings.
SIGMAFAST OPD has been used in saliva- virus-like particles (VLP) binding assay. It has also been used to develop enzyme linked immunosorbent assay (ELISA) plates for the detection of rituximab in rat serum samples.

Features and Benefits

SIGMAFAST OPD Tablets require no additional buffers or steps to prepare an active substrate solution.


This substrate is hygroscopic and light sensitive


Each tablet set dissolved in 20 mL deionized water yields a ready-to-use buffered solution containing OPD and urea hydrogen peroxide.

One OPD tablet and one urea hydrogen peroxide/buffer tablet, dissolved in 20 ml of water, provides 20 ml of ready-to-use substrate. When the tablet is dissolved in this manner, the final concentrations will be 0.4 mg/ml OPD, 0.4 mg/ml urea hydrogen peroxide, and 0.05 M phosphate-citrate, pH 5.0. Tablets are individually packaged in foil packets.

Legal Information

SIGMAFAST is a trademark of Sigma-Aldrich Co. LLC

Safety & Documentation

Safety Information

Signal word 
UN 3316 9
WGK Germany 


Certificate of Analysis (COA)

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Certificate of Origin (COO)

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Protocols & Articles


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