A band around 1,630 cm−1 is assigned to the bending vibration of water molecules bound to the silica matrix. No peak was found between 2,800 and 3,000 cm−1. It means that there were no original organic compounds in the silica after controlled combustion and extraction. This result corresponds well with the carbon measurement by CHN analysis reported in Table 4. The FTIR spectra showed no significant changes in the peak position for extracted silica and nanosilica.