Re: Sorting Difficulties

Joseph Webster (
Mon, 21 Oct 1996 10:28:11 +1100

Hi Vincent et al
Re: droplet breakoff drifting;

The main causes of this I have experienced are
1 - Not sufficient warmup time
2 - Air bubbles in the nozzle
We use an extra inline filter in the saline tubing for sterile sorting,
and sometimes there have been bubbles there too.

We try to run the drop drive and deflection field for at least half an
hour before starting a sort, and flush the nozzle with 70% ethanol to
get any air out. (you then must get out the ethanol of course...)

My experience is limited to FACS IV, FACS 440 & FACStar Plus, so I
can't comment on other machines.
On the FACStar Plus I routinely prepare as above, make a slight
correction (usually one quarter drop, sometimes half) after about
half an hour sorting and if there is any further change over several
hours I wonder why.

Cheers, Joseph Webster

At 03:45 PM 18/10/96 -24000, Vincent Falco wrote:
>To All:
>In the time course of performing a sort (1-2hrs.) my sorter is experiencing
>drifts in droplet breakoff(as observed by the camera screen on the
>sorter).When this is observed,the sort is stopped and the drop delay/droplet
>breakoff is checked by performing the ususal bead count matrix over several
>drop delays.Typically, the drop delay has in fact changed from its original.
>While I want to hear any and all responses as to what the problem may be(my
>performance or the sorter)assume for the time that there is absolutely no
>clogs,no air/fluidic leaks, and all electronics completely in fine tune.
>New England Medical Center

Joseph Webster (O.I.C. Flow Cytometry)
Centenary Institute of cancer Medicine & Cell Biology
Locked Bag No.6, Newtown, NSW 2042, AUSTRALIA.
Ph: 61-2-9565-6110 Fax: 61-2-9565-6101

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