BCECF is a fluorescent probe commonly used to measure pH. It is a dual-excitation ratiometric pH indicator with a pKa of ~6.98. Measurements of pH are made by determining the ratio of emission intensity, detected at 535 nm, when excited at 490 nm versus the emission intensity when excited at 440 nm. BCECF is membrane impermeable, whereas the acetoxymethyl ester, BCEBF-AM is membrane permeant.
