Propidium Iodide Spectrum
Molecular Structure of Propidium Iodide. Diagram depicts the skeletal structure of propidium iodide, chemical formula C27H34I2N4.
Propidium Iodide (PI) binds nucleic acids by intercalation in the bases. When bound to nucleic acid it has an excitation maxima ~535 nm and an emission maxima ~615 nm. On a flow cytometer PI is typically excited by 488 or 561 nm and can be detected in a 610/20 bandpass.
Propidium Iodide Spectrum. Analysis of excitation, dotted line, and emission, solid line, of propidium iodide in aqueous solution.