Comet Labs WN591 Manual de usuario descargar pdf (Pagina 9)

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Figure 2. The path of light through a microscope during observation of fluorescence of ethidium

bromide. A typical microscope setup is shown, where the excitation light is passed to the slide

through an objective. For ethidium bromide, excitation light is green, emission light is orange. The

slide is illuminated by light from a mercury lamp (A). A mercury lamp emits light of different

wavelengths across the spectrum of visible and UV light. Only green light passes through the

excitation filter. DNA-bound ethidium bromide is excited by the green light and emits weak orange

light, which can be detected either by looking through the eyepieces (B) or by a camera (C).

Because relatively much of the excitation green light is reflected in all directions, an emission filter

is used that absorbs green light but passes light with higher wavelengths. See also Figure 1B for

explanation about the properties of filters.

filtering of excitation light

camera

source of excitation light

for fluorescence

(e.g. mercury lamp)

source of white light

(e.g. halogen lamp)

eyepiece

objective

microscope slide

excitation filter

detection of emitted light

through eyepieces

detection of emitted light

with a camera

emission filter

mirro

C B

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Comet Labs WN591 Manual de usuario Pagina 9