MQAE is a fluorescent indicator that is quenched via collision with chloride, and is more sensitive and selective than ³⁶Cl and microelectrode-based methods for chloride measurement in cells. In Vitro: Bath-applied to acute brain slices, MQAE provides high-quality labeling of neuronal cells and their processes^[1]. MQAE fluorescence is adequate and comparable method for measuring cAMP-dependent chloride transport in individual cells^[2]. MQAE can be used to measure intracellular chloride concentration in primary cultures of rat aortic smooth muscle cells (VSMC)^[3].