BCECF AM is the most popular green fluorescent, intracellular pH indicator. BCECF has a pKa of ~7, and exhibits pH-dependent, dual-excitation properties (Ex/Em 430nm/535nm and 490nm/535nm) for ratiometric analysis. Ratiometry is optimal for imaging applications, and reduces effects of photobleaching, heterogenous dye loading, and variable cell morphology. For HTS applications, BCECF can also be used in non-ratiometric mode using standard fluorescein excitation and emission settings. Excitation: 450, 500 nm | Emission: 530 nm | Purity: >95%