Intracellular pH: a new approach using quantitative microspectrofluorometry

Microspectrofluorometry is used to obtain the fluorescence spectrum of an isolated living cell. When cells are preincubated with 1,4-diacetoxy-2,3-dicyanobenzol, the components of the cellular fluorescense spectrum can be resolved, i.e. the characteristic fluorescence spectrum of each ionized form of the probe and the intrinsic cell fluorescence spectrum due to NAD(P)H. This allows the determination of the intracellular pH with good accuracy. Comparison between the intensity of the intrinsic cell fluorescence and the probe fluorescence intensity offers an opportunity to monitor the intracellular amount of a drug.<>