 Detection limit is in the parts per thousand range, but parts per million (ppm) are achievable with long collection times and concentration at top surface.XPS is routinely used to analyze inorganic compounds, metal alloys, semiconductors, polymers, elements, catalysts, glasses, ceramics, paints, papers, inks, woods, plant parts, make-up, teeth, bones, medical implants, bio-materials, coatings, viscous oils, glues, ion-modified materials and many others.Somewhat less routinely XPS is used to analyze the hydrated forms of materials such as hydrogels and biological samples by freezing the them in their hydrated state in an ultrapure environment, and allowing multilayers of ice to sublime away prior to analysis.