By Anonymous on Monday, July 5, 2004 - 11:04 am:

I would like to know how does helium acts to degass mobile phase and what are the recomendations for more efficient degassing.

-------------------------------------------------------------------------------------------------------
By Anonymous on Tuesday, July 6, 2004 - 07:05 am:

Helium gas is inert gas and lighter gas. when you purge your mobile phase with helium gas it will replaces the dissolved gases. Helium gas after replacing other gas helium itself escape from mobile phase and your mobile phase get degass.

-------------------------------------------------------------------------------------------------------
By tom jupille on Tuesday, July 6, 2004 - 10:35 am:

Uhhh, not quite. Helium works not because it's inert, but because it's *insoluble*. Dissolved gases from the mobile phase diffuse into the helium bubble and are swept from the system, but very little helium diffuses out of the bubble into the mobile phase because of helium's low solubility.

-------------------------------------------------------------------------------------------------------
By Anonymous on Tuesday, July 6, 2004 - 10:50 am:

Thank u all for our comments

-------------------------------------------------------------------------------------------------------
By HW Mueller on Tuesday, July 6, 2004 - 11:52 pm:

Well, it turns out that He dissolves enough in H2O to raise the baseline in a UV detector almost as much as N2 in H2O (comparing to H2O degassed under vacuum). It just seems to have less degassing tendency.
It appears that I mentioned that before, maybe I should publish these exprimental results.

-------------------------------------------------------------------------------------------------------
By HW Mueller on Wednesday, July 7, 2004 - 12:18 am:

Arghh, I meant "less outgassing tendency", above.

-------------------------------------------------------------------------------------------------------
By Anonymous on Wednesday, July 7, 2004 - 01:59 am:

Girls, in our lab, had tried to make me breath helium in and talk, while exhaling it. They said, my voice will be like that of cartoon creatures.

-------------------------------------------------------------------------------------------------------
By Alexander on Wednesday, July 7, 2004 - 05:51 pm:

As I've heard, He has an unusual solubility - temperature dependence. While other gases increasingly soluble at lower temperatures, He has the lowest solubility in cold water and higher solubility in hot water. So, when you cool the degassed buffer, the excessive He will actually eliminate, sort of “preservingâ€