“…In contrast to a “freeze-drying” procedure 10 that means, in fact, the cooling of desiccated samples, the fast-freezing allows both volatile surface species and a thin, 1–2 nm, film of the aqueous phase containing near-surface solutes, adsorbates and adhered solid species to be kept. Cryo-XPS has been successfully used for the investigation of many objects, for example, electrical double layers, 8,11 the products of sorption and chemical reactions, including at metal sulfides, 12–15 living cells and viruses, 16 and so forth. However, a number of methodological questions remain unclear, requiring further investigation with a wide range of objects.…”