Antipyrine Based Arsenate Selective Fluorescent Probe for Living Cell Imaging

Condensation of salicylaldehyde and 4-aminoantipyrine has yielded a new fluorescent probe (APSAL) capable of detecting intracellular arsenate at the micromolar level for the first time. The structure of the probe has been established by different spectroscopic techniques and confirmed from X-ray crystallography. Common anions, viz., F-, Cl-, Br-, I-, N-3(-), NCO-, NO2-, NO3-, SCN-, CN-, CH3COO-, SO42-, ClO4-, and HPO42- do not interfere. The binding constant of APSAL for H2AsO4- has been determined using the Benesi-Hildebrand equation as 8.9 x 10(3) M-1. Fluorescence quantum yield of APSAL (0.016) increases more than 12 times upon binding arsenate ion.