Coumarinboronicacidpinacolateester (CBE) is a more soluble form of coumarinboronicacid that can be used to detect peroxynitrite , hypochlorous acid, and hydrogen peroxide. Peroxynitrite oxidizes CBE into the fluorescent product 7-hydroxycoumarin (COH), which displays excitation emission maxima of 332 470 nm, respectively.