Identifying quinone-like species on the surface of graphitic carbon and multi-walled carbon nanotubes using reactions with 2,4-dinitrophenylhydrazine to provide a voltammetric fingerprint

Quinone groups on the surface of edge-plane and basal-plane pyrolytic graphite electrodes, and, for the 1st time, bamboo-like multi-walled carbon nanotubes (b-MWCNTs), are labeled with a voltammetric tag, 2,4-dinitrophenylhydrazine (2,4-DNPH). The voltammetric response of these materials was studied in both aq. and nonaq. electrolyte solns., and mechanisms are proposed for each media involving the voltammetrically controlled cleavage of the 2,4-DNPH adduct. Thus, these materials can be used for potentiometrically controlled chem. release, and as such may find application in, for example, drug delivery systems. In aq. media, this cleavage results in the conversion of the surface quinonyl groups into surface arylnitroso species. This conversion is confirmed by studying the voltammetric response of the arylnitroso/arylhydroxylamine redox couple, formed after cleavage of the 2,4-DNPH adduct in the presence of L-glutathione, which was shown in the authors' previous work to react with arylnitroso species on the surface of graphitic carbon materials. [on SciFinder(R)]