Is anyone familiar with a problem of a fluorescence signal from beads
falling down over a course of few hours/a day on B-D FACSort analyzer?
Here are the details:
- We measure an Fl1 signal from FCS beads with 15.8K FITC in linear mode.
First thing in the morning the mean value read for the beads is ~ 550 on a
scale of 1024 ( laser was warmed up for 30 min).
- Beads are always in PBS 0.1% BSA and for every measurement we use fresh
beads. Beads are not expired.
- Every hour a signal drops 10-20 channels, so at the end of the day the
difference is ~80-160 channels.
- All "Instrument status" values are looking good and constant.
I have been experiencing this problem for a few months. In the mean time
the instrument underwent maintenance service , exchange of a board with FL1
electronics, cleaning etc..
"The problem" makes my life a little difficult so the question is how to get
rid of it. One can suggest a reward together with the solution ( if it works!).
Thanks for taking your time.
Visia
Visia Dragowska