Re: FACSCalibur Mistery

You could also check the hydrophobic (ptfe) filters on the air lines going 
to the bulhead tubing connector cluster near the air pump & pressure 
regulator board, as well as the one protecting the pressure tranducer behind 
the fluidic switch.  These can become partially blocked with water and offer 
a pressure resistance (any filter inline with the air line to the sample 
port should be checked first, since if this one is blocked the machine 
thinks it's pressuring the sample tube, but in fact only pressurises the 
filter).

(Checking for restrictions to flow in other tubing might help, there's 
sometimes a build up of algal/fungal growth in the tubing behind the fluidic 
control which may well interfere with pressure measurements)
----- Original Message ----- 
From: "Smith, Vidal" <vsmith@guavatechnologies.com>
To: cyto-inbox
Sent: Monday, September 27, 2004 10:48 PM
Subject: RE: FACSCalibur Mistery


> (1)Check for small leaks at the seal for the sample tube. (2)Check for 
> leakage via the
> droplet containment module.
>
> -----Original Message-----
> From: Cappella, Paolo [Nervianoms]
> [mailto:paolo.cappella@nervianoms.com]
> Sent: Wednesday, September 15, 2004 5:05 AM
> To: cyto-inbox
> Subject: FACSCalibur Mistery
>
>
> Dear Flow users,
> In my lab there is a mistery, a FACSCalibur Mistery... In our facility two
> BD FACSCaliburs full-optional with 96wells plate loader (MAS).
> This FACSCalibur have two different behaviors, also using manual injection
> port. The first cytometer, made in 2001, have more high acquisition event
> rate than the second one (around half rate), made in 2003 using same
> reference beads (Red Nile Pharmingen or others) and same flow rate
> (HI,Med,Low). Performance in terms of CV% on all two cytometers are below
> 2-3% on all fluorescence channels.
> I tell you what we did together BD peoples:
> * Check sheat pressure (around 4.5psi) and all connection at different
> times (6-month maintanance). Each time the problem didn't change.
> * Sample Voltage: On this Calibur we decided to decrease the setting
> (-0.2V) to increase pressure inside tube. A little increase was observed 
> not
> comparable to first cytometer. We also change pressure controller board 
> and
> the pressure trasducer was checked on first cytometer
> * Sheat pressure: we decide to increase a little bit the sheat
> pressure by regulator. Also in this case there wasn't appreciable results.
> * We change the needle and also the valves-group that some times gave
> some problems.
> Now we don't know really the next.
> I have two ideas about other causes:
> * Could sample is diluted into Flow Chamber due to not correct
> hydrodynamic focusing? In this case i think that CV% should be high. Is it
> true?
> * I read that to initiate flow is applied in SIP (Sample Injection
> Port) a burst of about 9 psi. Is it correct? Is possible check the real
> pressure inside SIP, expecially if is present in my FACSCalibur the
> additional pressure. If i had a lower burst this could be explain because
> rate is low and because sometimes the sample acquisition didn't start
> (using MAS autosampler).
> Can you help me?
> Paolo Cappella
> Flow Cytometry Unit
> Biology Dept. - Bdg.75
> Nerviano Medical Science srl
> Via Pasteaur 10 - I 20014 Nerviano
> tel. +390331581367
>
>
>
>
>
>