I have lyophilized the cell-free supernatant of Lactobacillus and tried to re-dissolve it in several solvents including ethanol, methanol, and ethyl acetate, but none of them worked properly (no dissolution). Since I cannot use water for GC–MS assays, I am looking for alternative solvents or approaches that could effectively solubilize the sample for analysis.

Has anyone encountered a similar issue or can suggest suitable solvents or preparation methods compatible with GC–MS?