Some calcium compounds, such as hydroxyapatite (HA), are widely recognized as materials capable of separating proteins, nucleic acids, and viruses in aqueous systems using chromatography. For this reason, exploring alternative routes for forming calcified resins is of great interest. One of these routes is the biomineralization or biomimetic process. The present study analyzes the calcification deposits obtained on chitosan substrates as potential adsorbents. Adsorption experiments were performed with acids and basic proteins (cytochrome C, bovine serum albumin (BSA), and trypsin inhibitor), and the capacity results were compared to an HA ion exchange liquid chromatography model. The correlation with chemical structures of deposits was also determined. Chitosan was shown to be a very strong absorbent of acid proteins, and calcification increased this capacity by more than 10 times.