Carbon Nanotube Enhanced MALDI MS: Increasing Sensitivity Through Sample Concentration

• Main Author: Schumacher, Joshua
• Format: Others
• Published: Scholar Commons 2010
• Subjects: Mass Spectrometry; Carbon Nanotube; Peptide Detection; American Studies; Arts and Humanities
• Online Access: http://scholarcommons.usf.edu/etd/3595; http://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=4854&context=etd

Matrix-assisted laser desorption/ionization (MALDI) is a technique used in mass spectrometry for the ionization of biomolecules. A matrix solution is mixed with the analyte molecules to be investigated, and then spotted onto a specialized MALDI plate. The solvents evaporate leaving only the re-crystallized matrix with analyte dispersed throughout the crystals. Sample ionization is accomplished with a laser in the MALDI instrument. The spot diameter of the target is usually several orders of magnitude larger than the diameter of the laser, making it necessary to perform multiple laser investigations to accurately evaluate the analyte in the target spot. Experiments were performed to utilize patterned areas of carbon nanotubes to provide sites for preferential crystallization of the liquid matrix/analyte solution, which led to lateral concentration for non-aqueous based matrices and produced a final dried matrix/analyte spot that was approximately the diameter of the laser spot at the point of investigation. This work shows the results of using aligned carbon nanotubes as the substrate for the matrix/analyte deposition and demonstrates an increase in signal to noise ratio and an improved detection capability of low analyte concentrations compared to the standard MALDI preparation technique.