Purification Methods
The free acid is purified by dissolving it in conc H2SO4 which on dilution precipitates resorufin and is filtered off, washed well with hot H2O and dried. [Eichler J Prakt Chem 139 113 1934.] Detailed UV and IR studies were reported by Musso & Mattheis Chem Ber 90 1814 1957]. [pKa: Musso & Rathjen Chem Ber 92 751 1959, Beilstein 27 1V 2263.]
The monoacetate [1152-14-3] M 252.2, m 2 2 3o is a fluorogenic substrate used for hydrolytic enzymes, and its fluorescence has Emax 593nm (Eex 500nm, in 0.1M phosphate pH 8.0 with lipase) [Kitson & Kitson Biochem J 322 701 1997]. [Beilstein 27 IV 2263.]
The O7-methylresorufin (7-methoxy-3H-phenoxazin-3-one) [5735-89-3] M 227.2, m > 2 2 0o has fluorescence at Emax 585nm (Eexcit 571 nm in deacylase solution) and is used to differentiate isoenzymes of cytochrome P-450. It is insoluble in H2O and dilute alkali but is soluble in EtOH and CHCl3 to give an orange yellow colour. [Kehrmann Justus Liebigs Ann Chem 372 352 1910, Beilstein 27 II 108.]
