Figure 7. The structural formulae of phloxine B in an acidic (left) and alkaline environment (right). In the alkaline range an aqueous solution of this dye fluoresces orange, whereas in the acidic range the fluorescence is quenched.

From

Fascinating school experiments with fluorescent dyes

Matthias Ducci

World Journal of Chemical Education. 2023, 11(3), 74-79 doi:10.12691/wjce-11-3-9