Ellman's reagent

Ellman's reagent
Names
	Preferred IUPAC name 5,5′-Disulfanediylbis(2-nitrobenzoic acid)
	Other names 3,3′-Disulfanediylbis(6-nitrobenzoic acid); 5-(3-Carboxy-4-nitrophenyl)disulfanyl-2-nitrobenzoic acid; Dithionitrobenzoic acid; 5,5′-Dithiobis(2-nitrobenzoic acid)
Identifiers
CAS Number	69-78-3 ;
3D model (JSmol)	Interactive image;
Abbreviations	DTNB
ChEBI	CHEBI:86228 ;
ChEMBL	ChEMBL395814 ;
ChemSpider	6018 ;
ECHA InfoCard	100.000.650
EC Number	200-714-4;
PubChem CID	6254;
UNII	9BZQ3U62JX ;
CompTox Dashboard (EPA)	DTXSID5058779 ;
	InChI InChI=1S/C14H8N2O8S2/c17-13(18)9-5-7(1-3-11(9)15(21)22)25-26-8-2-4-12(16(23)24)10(6-8)14(19)20/h1-6H,(H,17,18)(H,19,20) Key: KIUMMUBSPKGMOY-UHFFFAOYSA-N ; InChI=1/C14H8N2O8S2/c17-13(18)9-5-7(1-3-11(9)15(21)22)25-26-8-2-4-12(16(23)24)10(6-8)14(19)20/h1-6H,(H,17,18)(H,19,20) Key: KIUMMUBSPKGMOY-UHFFFAOYAD;
	SMILES c1cc(c(cc1SSc2ccc(c(c2)C(=O)O)[N+](=O)[O-])C(=O)O)[N+](=O)[O-];
Properties
Chemical formula	C14H8N2O8S2
Molar mass	396.34 g·mol−1
Melting point	240 to 245 °C (464 to 473 °F; 513 to 518 K) (decomposes)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Ellman's reagent (5,5′-dithiobis-(2-nitrobenzoic acid) or DTNB) is a colorogenic chemical used to quantify the number or concentration of thiol groups in a sample. It was developed by George L. Ellman.