RESUMO
Mesoporous carbon nanorods (MCNRs) were prepared from honey as the carbon source and by using crab (Brachyuran) shells as the hard template. The unique nanostructure of the MCNRs with their uniform mesoporous size, abundant defective sites and numerous oxygen-functional groups was characterized by nitrogen adsorption-desorption isotherms, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Cyclic voltammograms of a glassy carbon electrode (GCE) modified with MCNRs revel a higher peak current density and lower peak potential (-0.03 V vs. Ag/AgCl) for ascorbic acid (AA) electrooxidation compared to a conventional GCE and a carbon nanotube-modified GCE. Figures of merit for this sensor include (a) a wide linear range (10-2770 µM), (b) high electrochemical sensitivity (216.91 µA mM-1 cm-2) and (c) a low detection limit (2.3 µM). These compare favorably to the respective data for a CNT-modified GCE (50-2150 µM, 5.20 µA mM-1 cm-2 and 26.8 µM) and a plain GCE (100-2000 µM, 0.58 µA mM-1 cm-2 and 54.6 µM). The modified GCE was successfully applied to the determination of AA in (spiked) real samples including an injection, soft drinks and fresh lemon juice. Therefore, the new sensor can be considered as an affordable tool for electrochemical sensing of AA in real samples. Graphical abstract Mesoporous carbon nanorods (MCNRs) were prepared by using honey as the carbon source and crab shells as the hard template. The MCNRs modified a glassy carbon electrode (MCNRs/GCE) was used for the ascorbic acid (AA) detection by amperometry.