Differential Pulse Voltammetric Determination of Hydroxylamine at an Indenedione Derivative Electrodeposited on a Multi-Wall Carbon Nanotube Modified Glassy Carbon Electrode

The electrodeposited thin films of an indenedione derivative on multi-wall carbon nanotubes modified glassy carbon electrode (MWCNT-GCE) shows one pair of peaks with surface confined characteristics. The indenedione MWCNT modified GCE (IMWCNT-GCE) presents a highly catalytic activity toward hydroxylamine electro-oxidation. The anodic peak potential for hydroxylamine oxidation at IMWCNT-GCE is about 140 mV whereas at MWCNT-GCE and indenedione modified GCE (IMGCE), the peak potentials appear at about 505 and 525 mV respectively. The results show that there is an enhancement of the anodic peak current of hydroxylamine oxidation at IMWCNT-GCE as compared to the value obtained at IMGCE or MWCNT-GCE. The results also suggest that a combination of MWCNT and mediator definitely improves the characteristics of hydroxylamine oxidation. Furthermore, differential pulse voltammetry exhibits two linear dynamic ranges of 1.0-10.0 and 10.0-100.0 mu mol L-1 with sensitivity of 0.1955 and 0.0841 mu A L mu mol(-1) respectively and a lower detection limit of 0.8 mu mol L-1 for hydroxylamine. Excellent electrochemical reversibility of the redox couple, technical simplicity, and good electrocatalytic activity for hydroxylamine are the advantages of this modified electrode. Finally, the activity of IMWCNT-GCE was also investigated for hydroxylamine determination in two natural samples.