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.