RE: Area or height??

From: Gerhard Nebe-von-Caron (Gerhard.Nebe-von-Caron@Unilever.com)
Date: Wed Feb 28 2001 - 13:00:44 EST


After Howard wrote me that he hadn't said what I thought he said I have to
apologise. I was to dense to read "density of fluorescent.." and read
"intensity" instead.  I was actually trying to think about the slit scanning
peak to reflect the intensity distribution within the cell. In case of the
ideal doublet you get a 'twin peak' signal but still the correct area or
integral for the total event. Thus the peak in slit scans does not reflect
total fluorescence but the maximal signal density as said by Howard in the
first place.  I think I have to get a faster / digitised internal translation
chip (or a coffee).

Gerhard

by the way thanks for the pun Howard


Howard wrote:
 When the illuminating beam height is close to or smaller than the cell or
particle diameter, passage through the beam produces a "slit-scan"; the pulse
height is now proportional to the density of fluorescent or scattering material
in the cell, but not to the area.  The height is thus sensitive to shape; the
area is not, and that is why plots of peak vs. integral can be used to remove
data from many (but usually not all) doublets in DNA analysis in instruments
with small beam heights.



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