Dual Desorption Electrospray Ionization−Laser Desorption Ionization Mass Spectrometry on a Common Nanoporous Alumina Platform for Enhanced Shotgun Proteomic Analysis

A gold coated nanoporous alumina surface was used for dual ionization mode mass spectrometric analysis using desorption electrospray ionization (DESI) and laser desorption ionization (LDI). DESI and LDI mass spectrometry (MS) from the nanoporous alumina surface were compared with conventional electrospray ionization (ESI) mass spectrometry and matrix assisted laser desorption ionization (MALDI) for analysis of tryptic digests of proteins. Combined use of DESI and LDI offer greater peptide coverage than either method alone and comparable peptide coverage as with dual MALDI and ESI. This dual ionization technique using a common platform with same sample spot demonstrates a potential time and cost-effective tool for improved shotgun proteomic analysis.