FTIR - Deconvolution spectra of paper documents

Infrared spectra of paper samples often show many overlapped hands in the most significant region of 1400-1900 cm(-1). The digital deconvolution reveals the underlying information, as shown by some examples of both authentic items and reference samples, appositely prepared. The IR absorbance of oxidized groups (both unconjugated and conjugated) in cellulose, as well as gelatine, rosin and lignin can be detected with the deconvolution technique even in the presence of the broad band at similar to 1630 cm(-1) due to adsorbed water. The deconvolution technique allows a rough identification of the mechanism of degradation which leads to yellowing and browning of the paper samples.