For bromination, the mobile phase was a 0.001 M KBr mixture of water, methanol, and acetonitrile (6:2:2, v/v) with 350 ml of 4 M nitric acid for the 1 L mobile phase, and the column was an Agilent Sb-Aq (250 mm 4.6 mm and 5mm: Palo Alto, CA, USA).
Wavelengths for excitation and emissionwere 365 nm and 435 nm,
respectively.