The differences in chemical structure within activated carbon granules were estimated for oxidised and unmodified carbon substrates. Samples from various parts of the carbon granules were obtained using the spouted-bed attrition method. A commercial granulated active carbon (Norit R3ex) demineralised with concentrated HF and HCl acids was used. Suitable powdered and core samples were obtained by stripping off successive layers of granules from carbon oxidised with concentrated HNO3 and from unmodified carbon for comparison. The following techniques were employed to characterise the surface properties of these samples: selective neutralisation and pa-metric titration of functional groups, and transmission FTIR spectroscopy. The distribution of oxygen chemically bound to the internal surface of the granules is discussed on the basis of the results.