Synchrotron-based micro Fourier transform infrared mapping to investigate the spatial distribution of amorphous and crystalline calcium carbonate in earthworm-secreted calcium carbonate balls

A study was conducted to determine whether the amorphous calcium carbonate (ACC) in the granules was stabilised by organic molecules. Aside from good old fashioned scientific curiosity there were potential industrial benefits in understanding the stability of the different forms of calcium carbonate as this material is used in a whole host of industries. Calcium carbonate was easily identified using FT-IR spectroscopy (see Figure 2). Crystalline carbonate phases such as calcite have distinct bands, while ACC lacked the distinct vibrational band at approximately 714 cm-1).