Re: [ccp4bb] air bubbles in the Bio-Rad Duoflow system

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Small lysozyme crystals protocol
From: Jacob Keller j-keller2 {- at -} MD {- dot -} NORTHWESTERN {- dot -} EDU
Date: 2008-07-04

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Subject: Re: Small lysozyme crystals protocol
From: "Mathews, Irimpan" iimathew {- at -} SLAC {- dot -} STANFORD {- dot -} EDU
Date: 2008-07-04

Subject: Re: air bubbles in the Bio-Rad Duoflow system
From: Artem Evdokimov artem {- at -} XTALS {- dot -} ORG
Date: 2008-07-04

Most likely you have a reasonable pressure differential in some spot -
somewhere in the system air bubbles get compressed (and dissolved) under
high pressure, then the pressure drops as you reach the column, and the
bubbles re-form. This may not happen with water due to lower viscosity or
perhaps less initial bubbles. Moving the flow restrictor (backpressure
generator) may have something to do with this.

Solutions - try adjusting the backpressure valve to a considerably lower
value and move it back where it belongs. Check your system for kinks in the
tubing, clogged tubes, or user-installed thin tubes where the system design
calls for thicker ones.

Artem

-----Original Message-----
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Ailong
Ke
Sent: Thursday, July 03, 2008 5:13 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] air bubbles in the Bio-Rad Duoflow system

Hello All,

I own a Bio-Rad Duoflow system for almost a year. The machine lived
up to some of the recommendations I saw on this board. However, there
is this annoying problem with air bubbles entering columns and I
cannot figure out the source. The system would be free of any air
bubbles in the beginning, and performs fine when water is loaded
using needle/syringe into the 5ml superloop and then injected into
the column. When protein samples are injected the same way, a lot of
air bubbles would appear and get trapped inside the ion exchange
column, leaving yellowish marks on the Uno columns and eventually
reducing their performance. I've been a FLC/AKTA user for about ten
years and have never seen such problems. I doubt it is due to a
faulty injection valve because we recently had it replaced for other
reasons. We did move a backpressure generator (a little black piece)
from post-column position to before-column, otherwise we cannot run
sizing columns in a reasonable flow rate.

I'd like to hear if you have similar experiences and how you fixed
the problem. Thanks a lot!

Ailong

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CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Small lysozyme crystals protocol
From: Jacob Keller j-keller2 {- at -} MD {- dot -} NORTHWESTERN {- dot -} EDU
Date: 2008-07-04

Next message:
Subject: Re: Small lysozyme crystals protocol
From: "Mathews, Irimpan" iimathew {- at -} SLAC {- dot -} STANFORD {- dot -} EDU
Date: 2008-07-04