The composition of the desired mobile phase is dictated by the intended use.

If you want to analyse amino acids than phospate is probably not suitable, since its second pKa around 7 is to high for usual amino acid separations.

Marie-Laure Fauconnier

Hi Dr Rawaah Y. Al-sharrab . I hope the following link could help:

https://www.thermofisher.com/om/en/home/life-science/cell-culture/mammalian-cell-culture/reagents/balanced-salt-solutions.html?gclid=Cj0KCQjw7MGJBhD-ARIsAMZ0eetPQYF9s--HAMPEZmKIYAn1I-8gHkkGQkbirAljSVcDkTIB4bd34GIaAmRvEALw_wcB&ef_id=Cj0KCQjw7MGJBhD-ARIsAMZ0eetPQYF9s--HAMPEZmKIYAn1I-8gHkkGQkbirAljSVcDkTIB4bd34GIaAmRvEALw_wcB:G:s&s_kwcid=AL!3652!3!391186515811!p!!g!!phosphate%20buffer%20saline&cid=bid_clb_cce_r01_co_cp0000_pjt0000_bid00000_0se_gaw_nt_pur_con

Jos Wielders thanks but I'm not using phosphate buffer as mobile phase, I want to use it as a surrogate matrix to simulate the plasma if possible.

Thanks Ali

I will ask her

Dear Rawaah

Do you use surrogate matrix to prepared calliberation standard?

Thanks Aref Wazwaz

And I'm not a Dr., Just a graduate student

Yes Ali

I want to use to prepare calibration curve, limit of detection and quantification, accuracy, precision and recovery. (Partial validation)

Unfortunately, the second pdf file refuses to download

I hope its meet your needs

Thanks a lot Ali

The second two.

Thanks a lot Ali, it is useful

Dear Rawaah,

many thanks for sharing this very interesting technical question with the RG community. As an inorganic chemist I must admit that I'm absolutely not a proven expert in biochemistry. However, I just came across a potentially useful article which might help you in your analysis. Please have a look at this paper:

Surrogate matrix and surrogate analyte approaches for definitive quantitation of endogenous biomolecules

Article Surrogate Matrix And Surrogate Analyte Approaches For Defini...

Unortunately this article has not been posted by the authors as public full text on RG. However, it is not that old (2012) and three of the authors have RG profiles. Thus you have a good chance to request the full text directly from one of the authors via RG (provided it is of interest to you).

Good luck with your work and best wishes!

Thanks alot, Frank T. Edelmann

Hope you a lot of luck in your work too