Post Sort Quenching

BIGOS@Darwin.Stanford.EDU BIGOS at Darwin.Stanford.EDU
Mon Feb 10 03:22:28 EST 1997


Dave Parks and I spent some time looking at loss of 
fluorescence of PE to try to figure out why low power 
Fascans did better than high power jet-in-air sorters at 
measuring PE stained cells. We determined the PE 
saturation curve and found that the dye saturated 
significatly at 100mW. Moreover, we observed that with 
several hundred milliwatts of 488nm illumination, PE was 
kicked into some unusal state from which it didn't 
recover.  Re-analysis of sorted cells minutes later had 
lost up to 45% of their origional fluorescence. With 
less laser illumination, this effect was minimized. For 
FITC we did not notice much change - 5% at most. We did 
not look at Cy5PE at that time.

>From our experience we would expect that with the low 
laser power that you are using (15mW) the losses for 
FITC and PE will be small.

-Marty Bigos
Stanford Shared FACS Facility



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