Transition metal oxide nanoparticles as surfaces for surface-assisted laser desorption/ionization mass spectrometry of asphaltenes

Abstract

We report the first use of NiO, Fe₃O₄, TiO₂, and Co₃O₄ nanoparticles as surfaces for surface-assisted laser desorption/ionization (SALDI) mass spectrometry of asphaltenes. Higher <i>signal-to-noise</i> ratios (S/Ns) for asphaltene species were observed using NiO and Fe₃O₄ nanoparticles for SALDI as compared to LDI, where both surfaces consistently provided 2- to 3-fold improved S/Ns. The new SALDI detection method showed reliable adsorption data measuring supernatant solutions after 24 hour asphaltene adsorption on NiO, Fe₃O₄, and Co₃O₄. These results indicated that NiO has a higher adsorption affinity than Fe₃O₄ and Co₃O₄ for asphaltene molecules, corroborating reported asphaltene adsorption on metal oxide nanoparticles.