Evaluation of Excitation Light Sources for Incident Immunofluorescence Microscopy

A variety of fluorescent excitation light sources were compared using a standard fluorescein solution or a bacterial conjugate with immunofluorescent microscopy. Quantitative data were obtained with microscope photometric apparatus. Both the quantitative data and comparative conjugate titering suggest that the 450-W xenon arc excited significantly more fluorescence than did the more commonly used 250-W mercury arc or the 100-W halogen lamp. The conjugate could be diluted 4 to 32 times more using the 450-W xenon. Additional advantages of 450-W xenon excitation include sufficient energy of wave lengths between 470 to 490 mm, thus permitting narrow-band excitation resulting in less autofluorescence and the ability to perform fluorescent-antibody procedures without the darkening of ambient room light.