No! Obviously, something is WRONG with your method.

I Found a published paper with low recoveries ( =32%). The authors justified it by that the method could nt regenerate all the compounds.

Dear Bouchra!

It depends on the properties of the materials you are dealing with and which solvent you are using. Sometimes changing parameters can affect the efficiency like flow rate and mixing speed (rpm) so try to make an optimization to your process. And please check the system you are working with.

Regards

Yahya

Thank you Mr JANI for your answer.

I'm workin with a GC-MS as a method of separation for detection of pesticides by liquid liquid extraction in plasma.

I think it's related to my matrix that can interfer my extraction. Also an evaporation step is used in my process.

Why did you give up so easily? Who said that method development is easy? It is the nature of liquid-liquid extraction that you will not get 100% in the first shake, let alone getting proper solvent to do the job. To check the recovery, please be certain that you don't have other factors such as matrix effect as part of the evaluation because it may skew the result. You need to check on pure solvent and need to study the nature of the analyte. Is it ionizable with basic or acid functional group and of course the solubility of the analyte in your chosen solvent. How about the stability? Keep trying till you get above 80% and don't give up so easily. We are here to help.

Thank you very much for your reconforting answer.

That's the start of the hard work that it need.

Indipendently from what you do in your extraction procedure, I think you agree with me about that nothing is wrong in the measurements. You have to find a better solvent for this extraction. Check the nature of your chemicals compounds that you want to extract remembering that "similar dissolves similar". Try to find on literature if someone else tried to extract this compounds and which solvents he used for that. It will be a good beginning.

Good luck!

Here is the example. I am trying to extract beta carotene from cat food using Acetonitrile water salting out ( QuEChERS method). Salt will separate water from acetonitrile and lipophilic compound should be moving into the acetonitrile phase. However, my recovery is only 50%. Checked the literature and found that most methods use hexane. I switched to hexane and recovery is more than 90%.