Fluorescence analysis of cells using a laser light source.

A quantitative microfluorometric instrument is described that employs a helium cadmium laser (442 nm) as the illumination source. The instrument consists of a double grating monochromator in front of a gallium arsenide photomultiplier that is interfaced with a desktop computer. The versatility of the instrument in making quantitative nucleic acid measurements on acridine orange and Feulgen-Schiff stained cells is demonstrated. The ploidy levels of several populations are easily determined, and the Feulgen fluorescent emissions are considerably greater than those obtained with a standard mercury lamp.