(208a) Effective Peptide Mass Spectrometry in High Salinity Environment Using Surface Peptide Adsorption / Desorption Kinetic Model

Signaling peptides have been known to have important role in the physiological mechanisms. Currently available approaches for analyzing peptides have drawbacks such as loss of peptides and complicated steps for sample preparation. We developed an efficient platform for mass analysis of neuropeptides which has a patterned surface adsorbing peptides. Drop-drying a droplet of neuropeptides dissolved in artificial seawater on a pattern surface pushed the crystallized salts toward the edge via coffee ring effect as the water evaporated, while collecting peptides on the central C18-terminated gold region via hydrophobic interaction. Our approach greatly simplifies the sample preparation for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). We also found that our patterns can be regenerated and used 5 times or more without any performance degradation. We have developed a simple kinetic model that describes the correlation between the evaporation rate and the surface coverage of peptides. The model describes adsorption-desorption kinetics using adsorption equilibrium constant, and calculate the adsorption of peptides onto C18-terminated silicon substrate. Moreover, the performance could be dramatically increased by concentrating absorbed peptides into a crystal using PDMS contact printing. Applying these drop-dry methods to MALDI-MS sample preparation potentially enables high-throughput analyses, including time-lapse mass analysis. Our approach is easily accessible to researchers who do not have special expertise in mass spectrometry, so it is possible to contribute to bringing new ideas to neuropeptide analysis.