| Product Name | o-Phenylenediamine dihydrochloride, tablet, 30 mg substrate per tablet |
| Quality Level | 200 |
| Form | Tablet |
| mp | 258 °C (dec.) (lit.) |
| Solubility | water: 1 tablet/10 mL, clear, colorless |
| storage temp. | 2-8°C |
| SMILES string | Cl[H].Cl[H].Nc1ccccc1N |
| InChI | 1S/C6H8N2.2ClH/c7-5-3-1-2-4-6(5)8;;/h1-4H,7-8H2;2*1H |
| InChI key | RIIWUGSYXOBDMC-UHFFFAOYSA-N |
| Manufacturer | Sigma-Aldrich Solutions |
General Description
o-Phenylenediamine dihydrochloride is a binucleophile and its condensation with α,β-unsaturated carbonyl compounds and aldehydes yields benzimidazoles.
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.
Application
o-Phenylenediamine dihydrochloride has been used as a substrate for horse radish peroxidase in detecting:
- human immunoglobulin
- CTLA4Ig in serum samples
- albumin in culture medium
Preparation Note
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 ÎĽl of fresh 30% hydrogen peroxide per 100 ml of substrate buffer solution, immediately prior to use. Tablets are individually packaged in foil packets.