Figure 4.

Fluorescence response of R19-S to hypohalous acids, chloramines, and bromamines. Reactions were carried out in PBS by mixing 10 μm R19-S and 10 μm of each oxidant while vortexing. The fluorescence response was measured at 5 (gray bars) and 60 min (black bars) using a platereader. TauCl, taurine chloramine; TauBr, taurine bromamine. Results are expressed as a percent of the fluorescence observed with HOCl at 60 min (white-filled bar) and are mean ± S.D. from three independent experiments. The products with HOI, as well as having high fluorescence, showed a different UV-visible spectrum from that with HOCl, with higher absorbing peaks in the 515 nm excitation band region.