CAS Registry Number

CAS 69-78-3 — 5,5'-Dithio-bis(2-nitrobenzoic acid)

5,5'-Dithio-bis(2-nitrobenzoic acid), also known as DTNB or Ellman's reagent, is a chemical used to quantify free thiol groups in biological samples. It reacts specifically with sulfhydryl groups to produce a yellow-colored anion detectable at 412 nm. CAS: 69-78-3, Molecular Formula: C14H8N2O8S2, Molecular Weight: 396.35 g/mol, Storage: 2 to 8 °C, Signal Word: Warning. Molekula supplies 5,5'-Dithio-bis(2-nitrobenzoic acid) from research to bulk quantities with full documentation and ISO 9001:2015 traceability.