DAPI, which is used in an optical microscope that uses fluorescence, has a chemical formula of C16H15N5 with a molar mass of 277.331 gmol.
Chemical formula C16H15N5 Molar mass 277.331 gmol It is used extensively in fluorescence microscopy. A fluorescence microscope is an optical microscope that uses fluorescence instead of, or in addition to, scattering, reflection, and attenuation or absorption, to study the properties of organic or inorganic substances. 
