3,3 ', 5,5'-tetramethylbenzidine

Structural formula
General
Surname	3,3 ', 5,5'-tetramethylbenzidine
other names	TMB
Molecular formula	C 16 H 20 N 2
Brief description	white, faint-smelling crystals
External identifiers / databases
CAS number 54827-17-7 EC number 259-364-6 ECHA InfoCard 100.053.949 PubChem 41206 ChemSpider 37605 Wikidata Q2259258
properties
Molar mass	240.34 g mol −1
Physical state	firmly
density	0.45 g cm −3 ( bulk density )
Melting point	168-171 ° C
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 315-319-335 P: 261-305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

3,3 ', 5,5'-Tetramethylbenzidine is a chemical compound from the class of benzidines and is used as a chromogen in immunohistochemistry .

After activation by peroxidase , TMB is blue with an absorption maximum at 650 nm. When sulfuric acid is added, TMB turns yellow at 450 nm. TMB is photosensitive.

Oxidation of 3,3 ', 5,5'-Tetramethylbenzidine (TMB)

use

TMB is used in biochemistry due to its color properties in the course of immunostaining , e.g. B. used in ELISA . Together with hydrogen peroxide and a phosphate-citrate buffer , TMB is used as a reaction starter. The fixation solution (sulfuric acid) brings about the color change after the samples have turned blue thanks to the TMB. If the reaction has stopped, the ELISA is evaluated with an ELISA reader ( photometer ).

Individual evidence

1. ↑ ^{a b c d e f} data sheet 3,3 ′, 5,5′-tetramethylbenzidine, ≥99% from Sigma-Aldrich , accessed on June 12, 2013 ( PDF ).
2. ↑ TL Martin, EJ Mufson, MM Mesulam: The light side of horseradish peroxidase histochemistry . In: J Histochem Cytochem . 32, No. 7, 1984, p. 793. PMID 6736628 .