Help me! AIR BUBBLES trapped in HPLC column...

[new...@plaza.snu.ac.kr]

*Urgent!*

Some or probably quite many air bubbles seem to be trapped in my HPLC column: 18C reverse phase column, pore size 7um.
Could you give me any suggestions to remedy this problem as quickly as possible?
I am much disappointed not to be able to proceed my experiments any more.
:-(

Thanks...

--
email : new...@plaza.snu.ac.kr
address :
Lee, Ji Hyun
Laboratory of Physical Pharmacy(Prof. Lee, Bong Jin)

Seoul National University
College of Pharmacy
Shinlim-Dong, Kwanak-Gu
Seoul 151-742, Korea.

[Dr E. Buxbaum]

new...@plaza.snu.ac.kr () wrote:
>*Urgent!*
>
>Some or probably quite many air bubbles seem to be trapped in my HPLC >column: 18C reverse phase column, pore size 7um. Could you g=

ive me any >suggestions to remedy this problem as quickly as possible?
>I am much disappointed not to be able to proceed my experiments any >more.

After some nasty remarks about prevention being better than cure I would
suggest to run the column with degassed solvent at the highest possible
flow rate (i. e., just before pressure cut out) for some 30 min or so.
The column should be upside down, so that the flow is upward.
Alternatively, if column construction allows, you could also try to run
it in reverse direction (i.e., feed the buffer into the exit of the
column).

[Harvard Morehead]

>
>
> *Urgent!*
>
> Some or probably quite many air bubbles seem to be trapped in my HPLC
column: 18C reverse phase column, pore size 7um.

> Could you give me any suggestions to remedy this problem as quickly as

possible?
> I am much disappointed not to be able to proceed my experiments any more.

> :-(
>
> Thanks...
>
>
>
> --
> email : new...@plaza.snu.ac.kr
> address :
> Lee, Ji Hyun
> Laboratory of Physical Pharmacy(Prof. Lee, Bong Jin)
>
> Seoul National University
> College of Pharmacy
> Shinlim-Dong, Kwanak-Gu
> Seoul 151-742, Korea.
>

I have had some luck by running overnight at a slow rate (0.1 ml/min for an
analytical column), with the column with the outlet up, so that any bubbles
will float trhough the column, and using very thouroughly degassed water.
The water will dissolve any air, and any bubbles will be pushed up through
the column.
Good luck!
-Harvard Morehead
harv...@aol.com
-no cool .sig
.

[kevin....@nottingham.ac.uk]

In article <5g20eq$d...@clarknet.clark.net>, Harvard Morehead
<har...@mail.clark.net> wrote:

> > *Urgent!*
> >
> > Some or probably quite many air bubbles seem to be trapped in my HPLC
> column: 18C reverse phase column, pore size 7um.
> > Could you give me any suggestions to remedy this problem as quickly as
> possible?
> > I am much disappointed not to be able to proceed my experiments any more.
> > :-(

I usually find that methanol or acetonitrile will dislodge gas trapped in
the column, I think what you should be asking is where this gas has come
from - check that you do not have a leak on the inlet side of your column
and thus that you are not actually introduciong air onto the column as you
run it.

[Rainer Hofmann]

new...@plaza.snu.ac.kr () wrote:
>Some or probably quite many air bubbles seem to be trapped in my HPLC column: 18C reverse phase column, pore size 7um.
>Could you give me any suggestions to remedy this problem as quickly as possible?
>I am much disappointed not to be able to proceed my experiments any more.

I guess the problem is poor degassing of solvents. At pressure levels
in a hplc column there aren't any free gas bubbles. But when pressure
drops at the column's outlet gas is set free again and bubbles disturb
detection.
You should use Helium to purge solvents and to keep them under a
Helium atmosphere. Online degassing systems are also available.

--
Rainer Hofmann rhof...@freiburg.netsurf.de
Kalkackerweg 20 fax: +49 761 4764136
79111 Freiburg phone: +49 761 4764135
Germany

[LIn Chung-Yen]

Rainer Hofmann wrote:

Hi:
You can degas solvents under sonicator and use air pump to remove air
bubles in solvent.
Try it, it works to me many years!!

Lin Chung-Yen
Institute of Zoology,
National Taiwan Univ.

Taiwan

[Dr E. Buxbaum]

LIn Chung-Yen <l...@formosa.g1.ntu.edu.tw> wrote:

> Hi:
>You can degas solvents under sonicator and use air pump to remove air
>bubles in solvent.
>Try it, it works to me many years!!

Just remember to do this with the pure chemicals, before you mix them
into the solvent mixtures commonly used in HPLC. If you degass the
mixtures, their composition may change due to evaporation.