Chromatography Forum

Hi everyone,

I have just a simple question to ask, if someone can give me an answer.
I would like to know what the stability of aminoacids in a water solution is.
I am trying to measure the concentration of an AA in plasma and I need to prepare a calibration solution of the aminoacid (the aminoacid is a drug allready disolved in water), two or three different concentrations but I do not know for how long I will be able to use them as calibrators for my method.
Please help me if you have any experince with that.

Thank you

Amino acids should be stable for the duration of your experiments, you might want to dissolve it in ACN/water vs. just water. Some of the amino acids, which contain hydroxy and carboxyl group might self-condense to form a ring or polymerize.

I've worked for weeks with aqueous solutions of amino acids without observing any deterioration, with the exception of glutamine. At low pH, it will deamidate and form pyroglutamic acid, with a half life of about 12 hours. If you just plan to use plain water, though, then there shouldn't be a problem.

Thank you for your responses.

I plan to use a Tranexamic acid solution to spike the plasma in order to have my calibration samples.
So this is why I asked for how long I can keep the Tranexamic acid aqueous solution at room temperature.
Let me know what you think about this.

Thanks