Increased Sensitivity for Neuropeptide Analysis by Atmospheric Pressure Matrix-Assisted Laser Desorption/Ionization (AP-MALDI) with Dynamic On-chip Preconcentration/Focusing Targets

摘要

We have shown the first successful coupling of the AP-MALDI to dynamic focusing targets, yielding substantial S/N ratio gains with negligible matrix background. The focusing effect allowed deposition larger sample volumes up to 20(mu)L and the S/N gains were 200-900 and 100-400 for hydrophobic and WCX focusing targets respectively as a result of the unique surface properties of the focusing targets. The enhanced sensitivity of AP-MALDI method enabled high-throughput protein identification from a diluted solution of a derivatized protein digest, with concentration as low as 2.10~(-8)M, preconcentrated and focused on hydrophobic target.