FIG. 9.
Impact of sample drying. Approximately 30 mg mouse liver was extracted using 40:40:20 with 0.1 M formic acid. The extract was divided into multiple 200 μl portions, dried using indicated methods, and redissolved in 200 μl of 10 mM NH4HCO3 in water. Samples were analyzed by LC-MS and the peak area of each compound compared to those in the original extract. It was found that the majority of metabolites, including uridine-diphosphate-glucose, were not affected by this solvent evaporation process. On the contrary, there was a significant decrease of NADPH, which partially oxidized to NADP+. NADH decreased as well but NAD+ did not increase detectably because the initial concentration of NAD+ is higher than NADH in this sample. Results are the average of four biological replicates and the error bar is the SD.