Spectral Archives

Howard Shapiro HPANDA at HARVARDA.HARVARD.EDU
Wed Dec 7 19:10:07 EST 1994


It would be a great idea to have fluorescence spectra available on line;
the raw data are probably more valuable than graphics files because, in my,
experience, one of the things people most often want to do with spectra is
plot other spectra over or alongside them.  It's fairly simple to use
spreadsheet programs to plot spectra from the tabular data.
The instrument we use does excitation and emission scans, and can produce
2-D spectral histograms as contour plots as well as more conventional
excitation and emission spectra.  The down side of this is that it
generates much bigger data files than it would if emission were measured
only at the excitation maximum and vice versa, but even the 2-D spectral
files are small compared to list mode flow data.
The big problems are normalization and correction.  Both, as currently
practiced, often involve use of solutions of a standard compound such as
rhodamine 101.  This material is very good in its applicable wavelength
range, but, when you start looking a red and IR-excited dyes, PMT
response goes to hell and there aren't well-recognized standards for
either response correction or normalization.  However, with enough of
us working on the problem and contributing data, we might arrive at
acceptable standards over the broad wavelength range of interest to
cytometer users.  Count me in.
--Howard





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