Dear fellow researchers

I started the procedure for amino acid extraction from rhizosphere soils planning for GC-MS detection. However, due to pandemics, GC-MS is no longer available, and now I have 0.22 um filtered soil suspensions prepared in 2 mM formic acid, which are frozen. The next step would be the passage through a DOWEX 50W-X8 column to remove interfering organic components and the recovery of the amino acid fraction retained by the resin in 6 M NH4OH. The eluate would then be dried on a rotary evaporator and the residue dissolved in 70% methanol and stored frozen until derivatization for GC-MS. But now we will move to ultra high performance liquid chromatography and we are asked to have our extracted amino acids in 6M hydrochloric acid. Any idea on how to change the extraction procedure from the solutions in 2mM formic acid we have now to the amino acids extracted in 6M HCl?