Adsorption of chiral aromatic amino acids onto carboxymethyl-beta-cyclodextrin bonded Fe3O4/SiO2 core-shell nanoparticles

作者：Ghosh Sudipa; Badruddoza A Z M; Uddin M S^*; Hidajat K

来源：Journal of Colloid and Interface Science, 2011, 354(2): 483-492.

DOI：10.1016/j.jcis.2010.11.060

• Magnetic nanoparticles
• Surface functionalization
• Carboxymethyl-beta-cyclodextrin
• Amino acids
• Chiral
• Adsorption

Surface of magnetic silica nanoparticles is modified by grafting with carboxymethyl-beta-cyclodextrin (CM-beta-CD) via carbodiimide activation. The functionalized magnetic core-shell nanoparticles (MNPs) are characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infra Red (FTIR) spectroscopy, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Vibrating Sample Magnetometer (VSM). These nano-sized particles are scrutinized for adsorption of certain chiral aromatic amino acid enantiomers namely, D- and L-tryptophan (Trp), D- and L-phenylalanine (Phe) and D- and L-tyrosine (Tyr) from phosphate buffer solutions. Adsorption capacities of the coated magnetic nanoparticles toward amino acid enantiomers are in the order: L-Trp > L-Phe > L-Tyr and under the same condition, adsorption capacities are higher for L-enantiomers than the corresponding D-enantiomers. All the equilibrium adsorption isotherms are fitted well to Freundlich model. FTIR studies depict significant changes after adsorption of amino acids onto nanoparticles. The stretching vibration frequencies of N-H bonds of the amino acid molecules are changed with complex formation through host-guest interaction. The structure and hydrophobicity of amino acid molecules emphasize the interactions between amino acid molecules and the nano-adsorbents bearing cyclodextrin, thus play important roles in the difference of their adsorption behaviors.

• 出版日期2011-2-15