Multiwalled carbon nanotubes modified electrodes with encapsulated 1,4-dihydro¬pyridine-4-nitrobenzene substituted compounds

Abstract

We report a voltammetric study of several nitroaromatic compounds such as the drugs: Nifedipine, Nitrendipine, Furnidipine and Nisoldipine in multiwalled carbon nanotubes (MWCNT) modified electrodes. All the compounds are strongly encapsulated in the three dimensional structure of the MWCNT and then reduced to the corresponding hydroxylamine derivatives. In the case of the modified electrode with MWCNT the answer in current are remarkably increased (approximately 40 times). This current multiplier effect is due to the nitro compounds are not only superficially adsorbed but this really encapsulated in the nanotube network covering the GCE. The nitro reduction peak was linearly dependent with the concentration of the nitroaromatic compound with detection limit (LOD) of 1.2 ∙10-8 mol∙L-1 and a quantification limits (LOQ) of 3.9∙10-8 mol∙L-1 for the case of Nitrendipine. All the studied nitrocompounds followed equivalents behaviours. Obviously from this result it is possible to postulate this technology as a very useful tool to develop analytical methods to determine these nitroaromatic drugs in real samples such as biological fluids. From the obtained results it is possible to conclude that for the studied 1,4-dihydropyridine-4-nitrobenzene substituted compounds a greater difficulty of reduction implies a greater ability to encapsulation.