Preparation of chiral graphene oxides by covalent attachment of chiral cysteines for voltammetric recognition of tartrates

The authors describe the preparation of a chiral graphene oxides (GOs) by covalent attachment of D- or L-cysteine using a one-step hydrothermal method. The resulting chiral functionalized GOs shows circular dichroism with intensities similar to those produced by the cysteines. This indicates that the chirality of cysteines is well preserved in the chiral GOs. The material is reasonably stable at temperatures from 20 to 200 degrees C and at pH values from 0 to 14. A glassy carbon electrode (GCE) was modified with the chiral GOs and then tested for recognition capability for L- and D-tartrate (0.5mM). The enantioselectivity of thechiral GOs appears to be the result of a synergistic effect where GO increases theconductivity and cysteine provides the chiral environment. The method is assumed to provide a useful general scheme for development of advanced carbonaceous materials with chiral recognition capabilities.