7954. Pyranine

Nomenclature

CAS number: 6358-69-6; 27928-00-3 (free acid)
8-Hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt; C.I. 59040; C.I. Solvent Green 7; HPTS.
C16H7Na3O10S3; mol wt 524.39.
C 36.65%, H 1.35%, Na 13.15%, O 30.51%, S 18.34%.

Description and references

Fluorescent dye with pH-sensitive spectral properties. Prepn: E. Tietze, O. Bayer, Ann. 540, 189 (1939). Use as a pH probe for liposome interiors: K. Kano, J. H. Fendler, Biochim. Biophys. Acta 509, 289 (1978); for phospholipid vesicles: N. R. Clement, J. M. Gould, Biochemistry 20, 1534 (1981); in yeast cells: A. Pe~na et al., J. Bacteriol. 177, 1017 (1995); in organelles: C. C. Overly et al., Proc. Natl. Acad. Sci. USA 92, 3156 (1995); in cytosol: B. S. Gan et al., Am. J. Physiol. Cell Physiol. 275, 1158 (1998). Effects of salt and polyethylene glycol concentration on pKa: Y. Avnir, Y. Barenholz, Anal. Biochem. 347, 34 (2005). Review of use as a biological stain: Conn's Biological Stains, R. W. Horobin, J. A. Kiernan, Eds. (BIOS Scientific Publishers Ltd, Oxford, UK, 10th ed., 2002) 399-400.

Chemical structure

Properties

Crystals from aq acetone. pKa 7.22 ± 0.04. Changes from blue to green at pH 6.5-7.5. Highly sol in water; slightly sol in glacial acetic acid. Absorption max (acidic aq soln): 403 nm. Absorption max (aq alkali soln): 454 nm. Emission max (aq alkali soln): 511 nm.

Use

Fluorescent pH indicator for biological systems. Biological stain; dye for solvents, cosmetics and pharmaceuticals.