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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Baeyesr on May 07, 2019, 05:46:44 AM

Title: Inconsistent liquid-liquid extraction yield.
Post by: Baeyesr on May 07, 2019, 05:46:44 AM

Hi everyone

I'm currently doing some tests on the robustness of a liquid-liquid extraction and i have some results i cannot explain and cannot find in literature.
When i repeat the extraction multiple times, al my components mostly stay within 10% around the mean extraction yield. But some components (palmitic acid, erucamide and n-heptacosane) vary a lot and non consistent between tests. Sometimes only palmitic acid varies, sometimes all three.
I have attached a screenshot of one of my tests with most components censored because of secrecy reasons.

Thanks in advance!

Additional info:
All tests are spiked with an automatic syringe from the same stock solution.
Every extraction test consist of 3 extractions at varying pH (Neutral, acidic, alkaline)
Extracion yield is the area under a peak on a GCMS measurement.

Title: Re: Inconsistent liquid-liquid extraction yield.
Post by: phth on May 10, 2019, 01:58:33 AM

Surfactants coat surfaces. I would guess precipitates/coats the surfaces, micelles, and hard to tell.  Salt concentration varies and that effects the surface tension and how the molecules interact with the surface.