Rhodamine B base is a fluorescent biological staining dye. Rhodamine B base is also used as a laser dye, tunable around 610 nm with the fluorescence yield being temperature dependent. Dyes and metabolites, Environmental Testing
Major impurities are partially dealkylated compounds not removed by recrystallisation. Purify the dye by chromatography, using ethyl acetate/isopropanol/ammonia (conc)(9:7:4, RF 0.75 on Kieselgel G). It has also been crystallised from a concentrated solution in MeOH by slow addition of dry diethyl ether; or from EtOH containing a drop of conc HCl by slow addition of ten volumes of dry diethyl ether. The solid is washed with ether and air dried. The dried material has also been extracted with *benzene to remove oil-soluble material prior to recrystallisation. Store it in the dark. [Beilstein 18 II 486, 18 III/IV 8246, 19/8 V 669.]
