Cell storage in a -80 °C freezer. To test the influence of low temperature storage on cell's metabolomics profiles, dried cells were stored in a -80 °C freezer, aiming to minimize changes in cellular metabolites. After the storage for 48 h, dried cells were taken out from the -80 °C freezer and then immediately placed into a desiccator (at room temperature) to eliminate water condensation. Cells were maintained in the desiccator for ~10 min, allowing them to reach the room temperature prior to SCMS experiments. To evaluate the influence of quenching and storage on cell metabolites, we prepared cells using different protocols and performed SCMS experiments (Figure ). Four groups of cells (i.e., Groups 1, 2, 3, and 4) were prepared using different processes (Table , Figure ). Cells in all groups were washed by AF solution before undergoing additional processes.