These light-emitting types of dyes like rhodamine & aniline blue are used to label proteins
... 
that is similar to fluorescein but has pH-independent fluorescence... [DOC] [TLE] Fluorescent Indicators for Intracellular pH - CiteSeerX [PAR] division and are observed in some common disease types such as ... fluorescent 
dye, emission at one carefully chosen wavelength may be ... tors were used to 
measure intracellular pH values before that .... Like fluorescein, 
carboxyfluorescein, and fluorescein sul- ......