Intracellular pH measurements using the fluorescence of 9-aminoacridine

Abstract9-Aminoacridine is a fluorescent weak base which distributes across the plasma membrane according to the pH gradient, and can be used to monitor changes in intracellular pH in eukaryotic cells. A calibration technique using the ionophore nigericin is described which allows us to measure intracellular pH values of chick skeletal muscle cells