Manganese oxide nanoparticle-assisted laser desorption/ionization mass spectrometry for medical applications

We prepared and characterized manganese oxide magnetic nanoparticles (d = 5.6 nm) and developed nanoparticle-assited laser desorption/ionization (nano-PALDI) mass spectrometry. The nanoparticles had MnO2 and Mn2O3 core conjugated with hydroxyl and amino groups、 and showed paramagnetism at room temperature. The nanoparticles worked as an ionization assistng reagent in mass spectroscopy. The mass spectra showed no background in the low m/z. The nanoparticles could ionize the samples of peptide、 drug and proteins (approx. 5、000 Da) without using matrix、 i.e. 2、5-dihydroxybenzoic acid (DHB)、 4-hydroxy-α-cinnamic acid (CHCA) and liquid matrix、 as conventional ionization assisting reagents. Post source decay spectra by nano-PALDI mass spectrometry will yield information of chemical structure of analyte