By Anonymous on Tuesday, November 18, 2003 - 09:12 am:

I get ghostpeaks if I just inject the eluent. I get a 2 min wide peak (about 2 mn after injection)without a column connected.

I changed some parts in the Rheodyne valve (8125) but it got worse (2 peaks instead of 1).

Also the pressure drops every time I inject up to 80 psi.

I am thankful for every suggestion.

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By shital pathak on Tuesday, November 18, 2003 - 01:06 pm:

I think Changing the purge(injector wash)solution and washing of injector should solve the problem.

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By Anonymous on Tuesday, November 18, 2003 - 05:34 pm:

What is mobile phase?

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By Anonymous on Tuesday, November 18, 2003 - 11:48 pm:

Is it possible that air enters your system when you inject?

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By Anonymous on Wednesday, November 19, 2003 - 12:54 am:

The mobile phase is 0.05% TFA in water. And I am using a capLC with flow rate of 2.5 uL/min.

I do think that air enters the system when I inject. The last time I tried, I got air spikes with the second peak.

Also, if I wash the sample loop there is air coming out. And I am sure I don´t put any air in with the syringe. But I don´t know if this happened recently or if it always did that because i never checked that before.

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By zelechonok on Wednesday, November 19, 2003 - 08:25 pm:

If you degas your mobile phase and not degas your sample you can see the air dissolved in your sample as a broad peak like you described.
If you bypass degasser (you can do it with isocratic method) this peak should disappear.