Titanium dioxide anatase as matrix for matrix-assisted laser desorption/ionization analysis of small molecules

The use of inorganic species as assisting materials in matrix-assisted laser desorption/ionization (MALDI) analysis is an alternative approach to avoid interfering matrix ions in the low-mass region of the mass spectra. Reports of the application of inorganic species as matrices in MALDI analysis of small molecules are, however, scarce. Nevertheless, titanium dioxide (TiO2) powder has been reported to be a promising matrix medium. In this study we further explore the use of TiO2 as a matrix for the MALDI analysis of low molecular weight compounds. We present results showing that nanosized TiO2 anatase and TiO2 rutile perform better as MALDI matrices than a commercial TiO2 anatase/rutile mixture. Moreover, when using nanosized TiO2 anatase as a matrix, high-quality mass spectra can be obtained with strong analyte signals and weak or non-existing matrix interference ions. Furthermore, our results show that the phase type plays an important role in the application of TiO2 as a MALDI matrix. Copyright (C) 2008 John Wiley & Sons, Ltd.