Surface modifications and analytical applications of graphene oxide: A review

Graphene oxide (GO) has attracted substantial interest in various fields of science and technology, owing to its remarkable mechanical, electrical and optical properties. It is prepared using the modified Hummers' method and employed as a precursor for the fabrication of graphene-based nanostructure materials. The facile synthesis of reduced graphene oxide and surface-modified GO using GO offers extensive opportunities in analytical chemistry. The surface modification of GO is realized via elemental doping and covalent and non-covalent bonding. It results in the functionalization of GO with different groups such as C–N, NN, N–H, and C–O–C. GO-based sensor technologies are extensively applied to identify numerous trace level analytes. These fluorescent, and electrochemical sensors are utilized primarily for detecting organic, inorganic, and biomolecules and for humidity sensing and bioimaging. The present review provides a holistic summary of not only the important literary aspects associated with GO but also the diverse practical applications of GO-based analytical strategies for the assaying of various target molecules.