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o-Phenylenediamine dihydrochloride

peroxidase substrate

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Linear Formula:
CAS Number:
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Quality Level




white to off-white


258 °C (dec.) (lit.)

storage temp.


SMILES string




InChI key


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General description

o-Phenylenediamine dihydrochloride (OPD) is a chromogenic substrate that can be used in enzyme-linked immunosorbent assay (ELISA) procedures as it utilizes horseradish peroxidase conjugates. The substrate produces a soluble end product that is orange-brown and can be read spectrophotometrically at 450 nm. The OPD reaction may be stopped with 3N HCl or 3M H2SO4 and read at 492 nm.


o-Phenylenediamine dihydrochloride has been used as a peroxidase substrate in enzyme-linked immunosorbent assay (ELISA) procedures.


May darken in storage.



Hazard Classifications

Acute Tox. 3 Oral - Acute Tox. 4 Dermal - Acute Tox. 4 Inhalation - Aquatic Acute 1 - Aquatic Chronic 1 - Carc. 2 - Eye Irrit. 2 - Muta. 2 - Skin Sens. 1

Storage Class

6.1C - Combustible, acute toxic Cat.3 / toxic compounds or compounds which causing chronic effects




Not applicable


Not applicable

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Areano Ethério Moreira de Farias et al.
Tropical animal health and production, 51(4), 745-752 (2018-11-14)
Goat breeding in the Northeast region of Brazil plays an important socioeconomic role. However, there are significant losses caused by sanitary deficits and infectious diseases, particularly caseous lymphadenitis (CL). Although CL is considered endemic in Northeastern Brazil, a comprehensive and
Bikash R Sahu et al.
The Journal of infectious diseases, 198(3), 434-443 (2008-07-01)
Filaria-specific antibodies of immunoglobulin (Ig) G, IgE, and IgM isotypes have been correlated with acquired immunity in the literature, but the status of filaria-specific IgA and its role in human filariasis has not been addressed. The present study attempts to
Andrew K I Falconar et al.
Clinical and vaccine immunology : CVI, 13(9), 1044-1051 (2006-09-09)
We compared dengue virus (DV) isolation rates and tested whether acute primary (P) and acute/probable acute secondary (S/PS) DV infections could be correctly classified serologically when the patients' first serum (S1) samples were obtained 1 to 3 days after the
E O'Connor et al.
Journal of immunological methods, 229(1-2), 155-160 (1999-11-11)
The ability to detect a protein is always limited to the sensitivity of the assays available. Progress in improving the sensitivity of protein detection will allow a more complete understanding of biological systems. Of particular interest to the field of
Guy Mollett et al.
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 69(7), 1130-1135 (2018-12-13)
Visceral leishmaniasis (VL), caused by the Leishmania donovani complex, is a fatal, neglected tropical disease that is targeted for elimination in India, Nepal, and Bangladesh. Improved diagnostic tests are required for early case detection and for monitoring the outcomes of


NBT-BCIP substrate system aids in western blotting and immunohistological staining, producing a blue-purple insoluble end product.

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