[Cytometry] FACScan sample flow rate very low

Raymond Lannigan rlannigan at cytekdev.com
Fri May 11 13:42:13 EDT 2012


HI David,
	Sounds like your event rate is really low, while having what appear to be
normal sample voltages. If you have a pressure gauge, try measuring the
sample pressure at the flow cell (green line). It should be approx. 4.6
PSI in HI and 4.1 PSI in low. If this is correct, remove the outer drip
tube from the sample injection probe to check the drip rate. The probe
should drip at a rate of 1 drop every 6-10 seconds. If your drip rate is
correct, check sheath flow rate at the input to the waste tank (orange
line). This should be 18mL/min.
Hope this helps,
Ray
Raymond Lannigan
Cytek Development Inc.
540-207-6709 (Cell)
804-234-8110 (office)
804-414-7789 (fax)






On 5/10/12 11:19 PM, "David Halvorsen" <david.halvorsen at sens.org> wrote:

>Greetings,
>
> 
>
>Our FACScan began to malfunction several weeks ago.  Initially air was
>flowing directly through the pressure transducer and purging the flow cell
>of sheath fluid.  After the transducer was replaced, the instrument began
>to
>read tagged cells and calibration beads as expected, but with a very low
>sample flow rate.  The FACSComp program fails the initial PMT test every
>time stating "event rate too low".
>
> 
>
>When I run samples of known concentration for a specified time, I get
>values
>that agree with an estimated flow rate of 0.038 uL/minute for the Hi
>setting.  The manual states that this rate should be 60 uL +-7ul per
>minute.
>
> 
>
>The sample voltages for different conditions are:
>
> 
>
>Lo 6.30 volts
>
>Hi 5.80 volts
>
>Standby initially at 8.64 volts, but drops to 6.45 volts over several
>minutes 
>
>When I interrupt a Lo or Hi run by moving the sample support arm to the
>side
>I get a voltage of 10.23 volts
>
> 
>
>Any ideas?
>
> 
>
>David Halvorsen
>
>Research Associate
>
>SENS Foundation
>
>110 Pioneer Way, Suite J,
>
>Mountain View, CA 94041, USA
>
>(650) 938-6100
>
> 
>
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