2577. Cresol Purple
Nomenclature
CAS number: 2303-01-7
4,4′-(1,1-Dioxido-3H-2,1-benzoxathiol-3-ylidene)bis[3-methylphenol]; m-cresolsulfonphthalein. C21H18O5S; mol wt 382.43.
C 65.95%, H 4.74%, O 20.92%, S 8.38%.
Description and references
pH sensitive dye. Prepn: W. R. Orndorff, A. C. Purdy, J. Am. Chem. Soc. 48, 2212 (1926). Solvent effects: J. Barbosa et al., Mikrochim. Acta 106, 327 (1992). Ionization and spectral properties: R. Casula et al., Talanta 40, 1781 (1993); M. C. Aragoni et al., ibid. 42, 1157 (1995). Titrimetric determn: K. Vytras et al., Analyst 114, 479 (1989). Use as pH indicator for emission of NO2 in museum collections: J. Fenn, Polym. Prepr. 37, 170 (1996); in wine: E. N. Gaiao et al., Analyst 124, 1727 (1999); in buffered solns: S. Paula et al., Biochemistry 38, 3025 (1999).
