Title: Sirius Red
CAS Registry Number: 2610-10-8
CAS Name: 7,7￠-(Carbonyldiimino)bis[4-hydroxy-3-[[2-sulfo-4-[(4-sulfophenyl)azo]phenyl]azo]-2-naphthalenesulfonic acid] hexasodium salt
Synonyms: C.I. 35780; C.I. Direct Red 80; Sirius Red F3B
Molecular Formula: C45H26N10Na6O21S6
Molecular Weight: 1373.07
Percent Composition: C 39.36%, H 1.91%, N 10.20%, Na 10.05%, O 24.47%, S 14.01%
Literature References: Sulphonated tetrakisazo dye. Dye molecules bind parallel to helical native collagen. Water and light stability: J. J. Porter,
Text. Res. J. 43, 735 (1973). Spectral study: J. P. Hart, W. F. Smyth,
Spectrochim. Acta 36A, 279 (1980). Staining mechanisms: L. Feldskov Nielsen
et al., Biotech. Histochem. 73, 71 (1998). Use as stain for collagen: F. Sweat
et al., Arch. Pathol. 78, 69 (1964); D. A. Lee
et al., J. Mater. Sci.: Mater. Med. 9, 47 (1998).
Properties: uv max (buffered): 220, 235, 290 nm (e 1.2 ′ 104, 1.3 ′ 104, 1.2 ′ 104). vis max (buffered): 420, 520, 545 nm (e 0.8 ′ 104, 2.5 ′ 104, 2.6 ′ 104). pK1-6 < 2; pK7.8 >13.
pKa: pK1-6 < 2; pK7.8 >13
Absorption maximum: uv max (buffered): 220, 235, 290 nm (e 1.2 ′ 104, 1.3 ′ 104, 1.2 ′ 104); vis max (buffered): 420, 520, 545 nm (e 0.8 ′ 104, 2.5 ′ 104, 2.6 ′ 104)
Use: Stain for connective tissue. Dye for cellulose fibers.
