Nanoparticle TiO2 Films Prepared by Pulsed Laser Deposition: Laser Desorption and Cationization of Model Adsorbates

Titanium dioxide is a low-cost photocatalytic material in the chemical industry. This work provides extended insights into the use of TiO2 nanostructures in laser-assisted laser desorption ionization (LDl) of small peptides and synthetic polymers. The investigation evaluates the interfacial morphologies in the nanoscale that enhance the LDI efficiency in nanoparticle-assembled TiO2 films prepared by lenitosecond and nanosecond linked laser deposition (PLD) at different laser wavelengths. It is shown that PLD provides robust substrates yielding LDI pulse energy thresholds and signal/noise ratios in the mass spectra for detection of canonized adducts that can be comparable to those obtained with TiO2 nanoparticle suspensions and with conventional organic matrices. The best LDI performance is found for nanosecond PLD crystalline substrates of the anatase polymorph and for femtosecond PLD amorphous substrates, with average nanoparticle sizes in both cases in the range of 25-55 nm.