derivatization of MOPS

[rafanugo]

Dear all
I am trying to measure by GCMS an analyte after derivatizated to trimethylsilyl. Standards samples in water give good results after drying with N2 gas and derivatization. But when trying to do the same in culture medium (to see real matrix efect) I am getting lower signals. I am wondering wether the MOPS compound (3-(N-morpholino)propanesulfonic acid, buffer) is reacting with the BSTFA+TMCS and then interfering in the reaction. Any experience about that would be wellcome
Thanks
Rafael

[Don_Hilton]

Any compound with an active proton will react with MSTFA/TMCS. While the amine functionality in the MOPS molecule does take up protons, it may not be a strong enough base to keep those protons from reacting with MSTFA/TMCS. Try adding some anhydrous pyridine in the derivitization. Or you may have to increase the quantity of MSTFA/TMCS.