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P7288 Sigma

o-Phenylenediamine dihydrochloride

tablet, 20 mg substrate per tablet




Dissolve one tablet in 0.05 M phosphate-citrate buffer, pH 5.0, to the desired concentration (typically an OPD concentration of 0.4 mg/ml is used). Add 40 μl of fresh 30% hydrogen peroxide per 100 ml of substrate buffer solution, immediately prior to use. Tablets are individually packaged in foil packets.


o-Phenylenediamine is a peroxidase substrate suitable for use in ELISA procedures. The substrate produces a soluble end product that is orange-brown in color and can be read spectrophotometrically at 450 nm. The OPD reaction may be stopped with 3 N HCl or 3 M H2SO4 and read at 492 nm.

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Suggested Laboratory Gloves

Laboratory GlovesThis substance has been tested against several types of hand protection for CE compliance. Click below to find the recommended gloves for handling this product.

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Safety Information

Signal word 
UN2811 - class 6.1 - PG 3 - MP - EHS - Toxic solids, organic, n.o.s., HI: all
WGK Germany 


Certificate of Analysis

Certificate of Origin

Protocols & Articles


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