In this study we apply the technique of depth profiling to analyse the concentration of elements in the near surface region of smart-phone display glass. We will look at the distribution of alkali and alkali earth metals - in particular K which is a key element in the glass toughening process. Two different depth profiling methods were used, monatomic Ar and Ar cluster, and a comparison is made regarding the ion bombardment effects of these two methods.  We emphasise the importance of ion choice when depth profiling inorganic materials in particular those containing light alkali metals.

Analysis of biomolecules on surfaces is essential to various applications of biosensors and biomolecule engineering. Matrix-assisted laser desorption/ionisation (MALDI) is now an established technique for mass spectrometry of biomolecules. Different matrix-analyte preparation protocols have been shown to influence the desorption or ablation process resulting in either high or low metastable fragmentation. It has been speculated that following laser ablation the velocities of the analyte and matrix can be regarded as a valuable and meaningful characteristic of the MALDI process. However, the interaction and distribution of the analyte with respect to the matrix is poorly understood. Here we study the distribution of a selection of biomolecules as a function of matrix material using high resolution imaging X-ray photoelectron spectroscopy (XPS).

XPS imaging is an important tool for investigating the lateral distribution of surface chemistry on the micron scale.  Photoelectrons emitted from core electronic levels of surface atoms may be focused to form a two dimensional image on a suitable detector to allow the lateral distribution of the photoelectrons to be determined.  AXIS spectrometers have a pulse counting delay line detector (DLD) system which allows images to be quantified.  Spectra may be generated from every pixel in an image hence the chemical state of a sample surface may be quantitatively determined at high lateral and high energy resolution.  In this example silicon dioxide particles dispersed on the surface of a silicon wafer were analysed to demonstrate the flexibility of XPS imaging.

Here we investigate the oxidation of Co(OH)₂ using the catalysis cell. The catalysis cell allowed us to treat the sample under high temperature high pressure conditions similar to those found in industrial reactors. Careful analysis of the XPS spectra generated after each successive treatment shows that once calcined above 200 ºC the surface of the catalyst changes from hydroxide to oxide. Peak fitting the Co 2p region identified Co to be present as Co₃O₄.