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gcms signal consistently decrease within the assay

Posted: Mon Sep 29, 2014 3:23 pm
by jiangds06
I saw signal decrease after each run. Sample preparation is liquid liquid extraction with ethyl acetate. Is this because of residual water in the ethyl acetate phase?

Re: gcms signal consistently decrease within the assay

Posted: Mon Sep 29, 2014 6:34 pm
by Steve Reimer
Increasing water in the MS source will cause a loss of response.

Re: gcms signal consistently decrease within the assay

Posted: Tue Sep 30, 2014 1:00 pm
by jiangds06
Thank you so much. So how can fix this issue?
Increasing water in the MS source will cause a loss of response.

Re: gcms signal consistently decrease within the assay

Posted: Tue Sep 30, 2014 2:17 pm
by bunnahabhain
Use anhydrous sodium sulfate to dry your ethyl acetate sample after extraction.

Re: gcms signal consistently decrease within the assay

Posted: Thu Oct 02, 2014 5:12 pm
by jiangds06
tried that. but analytes are adsorbed in the sodium sulfate.
Use anhydrous sodium sulfate to dry your ethyl acetate sample after extraction.