BIO RAD 170-6555, Инструкция по эксплуатации

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Software Reference
The Exposure Time is influenced by how intensely the fluorophore is emitting light. This, in turn, is pro-
portional to the concentration of the substance containing the fluorophore in the gel; greater intensity
means shorter exposure. The Exposure time... setting should prevent overexposure of bands of inter-
est; saturation is acceptable only if it is indicated for bands that will not be quantized.
To see the results of overexposure, select HiLite Saturated Pixels from the Options menu. This selec-
tion functions as a toggle: If a checkmark appears next to your selection, saturated areas are displayed
in yellow in the image and the amount of saturation can be read in the Pixel Table. To turn off the dis-
play of saturated areas, again select HiLite Saturated Pixels.
To detect underexposure, move the Marking Cursor over the centers of the bands of interest. As you
move the cursor watch the Mouse Table. The Gray pixel values should range between 50,000 and
60,000. If the center of the band shows a value below 50,000, the image may be considered underex-
posed.
If the image shows lanes of differing intensities, adjust the SE1000 Camera Control window’s Percent
Saturation... to limit the percentage of detectors and corresponding pixels that are saturated within a
region. For example, if your band(s) of interest were averaging a 12,000 pixel value at a .8 second
exposure time, you might want to take a second exposure with the exposure time set to 1.6.
The table below provides guidelines for typical gels, and is intended as a starting point for imaging.
Table 2.
Typical Exposure Strategies
Image Type Percent Saturation Exposure Time
Oligosaccharide 0 - 5 –
Monosaccharide - 6 seconds
Protein 25 –
DNA 0 - 5 –
Note that prolonged or repeated exposure of the gel to UV light can lead to bleaching, which is the result
of exposing a fluorescently tagged gel to the UV light source for a period which causes the fluorophore
to diminish its light output.
Image Resolution
The image may be acquired for display at Normal Resolution or High Resolution. To capture the image
and present it as data, a series of exposures is taken whenever the camera is triggered. The data is
averaged to create the final pixel values which are used for display and analysis. Selecting High
Resolution doubles the number of exposures that are taken. This yields a higher image quality, but risks
bleaching the gel. For this reason, Normal resolution is recommended.