Molecular Modeling of Montmorillonite Adsorption

The molecular model for montmorillonite was drawn in ISIS Draw 2.0 and then imported into HyperChem 8.0. The aflatoxin, carnitine, and choline structures were energy-minimized using the semiempirical quantum mechanical AMI method. The model was constructed using the unit cell coordinates of muscovite.³⁴ These coordinates were then converted to orthogonal coordinates in an Excel spreadsheet that was constructed from a public domain C program. The unit cells were replicated in three-dimensional space by applying the symmetry operations for a C2/c space group.³⁵ The d00l spacing of the model was then set to the corresponding dimensions of the exchanged montmorillonite (21 Å) based on the report of Greenland and Quirk.³⁶ Aflatoxin, carnitine, and choline were inserted into the interlayer and on the external surface³⁷ to illustrate the proposed sites of aflatoxin adsorption.^{1 (link),2 (link)}