Results from a study of the degradation products formed by the oxidation at the wet/dry interface of pure cellulose Whatman filter paper n. 5 are presented. Analysis techniques were thin layer chromatography (TLC) Fourier transform infrared spectroscopy (FTIR) and gas chromatography coupled to mass spectrometry (GC/MS). Their advantages and drawbacks in identifying the degradation coumpounds of the wet/dry interface are discussed. IR spectra showed the presence of carbonyl groups from aldehydes and ketones of polar and mildly polar compounds and the presence of ethylenic links of less polar compounds. The presence of conjugated systems could explain the brown colour observed. TLC and GC/MS could identify sugars and uronic acids in the degradation products extracted from the cellulose. Their formation from the cellulose chain is explained.