A novel ratiometric fluorescent probe for selective detection of bisulfite in living cells

A new type of ratiometric fluorescent probe, 8-(diethylamino)-2-methyl-4-oxo-4H-pyrano[2,3-b] chromen-10-ylium tetrafluoroborate (APCT), is reported. A new type of ratiometric fluorescent probe, 8( diethylamino)-2-methyl-4-oxo-4H-pyrano[2,3-b] chromen-10-ylium tetrafluoroborate (APCT), is reported. This probe can successfully detect bisulfite anions with a detection limit of 6.1 X 10(-7) M based on Michael-type addition reaction in pH = 7.4 Tris buffer solution containing 70% DMSO (v/v). The response time of the probe is approximately 5 min. Upon treating with bisulfite anions, the probe exhibits an obvious blue shift from 560 nm to 510 nm and the fluorescence intensity ratio at 510 nm and 560 nm (I510/I560) displays a good linear relationship with the concentration of HSO3- in the range of 20-120 mu M. Additionally, the preliminary cell imaging experiments using HeLa cells demonstrate that the probe can be used to detect intracellular bisulfite anions.