weird emission spectral peak of a blank buffer

Posted by yuansheng sun on
URL: http://confocal-microscopy-list.275.s1.nabble.com/weird-emission-spectral-peak-of-a-blank-buffer-tp7579220.html

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

Dear Listers,

Recently, we got two weird peaks in the emission spectrum of our blank
buffer (1-molar Tris at pH 7.3), measured on a spectrofluometer.  The Tris
buffer is what we use to make our dye solutions to be measured on the
spectrofluometer.  It is always freshly prepared.  One small peak of the
blank buffer shows at about 20 nm plus the excitaion wavlength
and the other huge peak appears at about twice of the excitation
wavelength.  We found this with the emission spectrum measurements using 5
different excitation wavelengths - 250 nm, 280 nm, 285 nm 300 nm, and 350
nm.  We also observed the similar things with DI water.  Any explanation
and suggestion would be appreciated.  Thanks a lot in advance.

Yuansheng Sun