Evaluation of Electrospray Ionization Effects on Jurkat T-Human Leukemia Cell Washing Buffers Lipid Extraction Methods by LC-MS

摘要

Cell washing with traditional buffers (PBS and HEPES) results in a reduced peak area for lipid species. HEPES is not a compatible buffer for LC-MS lipid analysis due to a 75-95% decrease in peak area for the LPC and PC lipid classes. Preliminary results suggest the reduction in peak area can be attributed to less efficient lipid extraction in the presence of HEPES. Residual PBS causes ion suppression of lipids due to incomplete removal of salts present in the buffer (NaCl, KCl, Na_2HPO_4, CaCl_2, and MgCl_2. Ammoniated buffers enhance the ESI signal as shown by an increase in peak area and ion intensity for the ammoniated adduct of the PG and TG lipid standards. The Folch lipid extraction method is better than the MTBE method for global lipid analysis of Jurkat cells due to higher lipid recovery and sample-to-sample reproducibility. Future investigations will evaluate the lipid extraction process for cells washed with HEPES using spiked lipid standards and endogenous compounds. Additionally, lipid classes influenced by the MTBE and Folch extraction solvent systems of cells will be further identified.