A Cubic Silsesquioxane Chemically Modified with a PAMAM Dendrimer G0: an Application in Electro-Oxidation of Ascorbic Acid

Abstract

Octa-(3-chloropropyl) octasilsesquioxane (SS) was functionalized with a PAMAM dendrimer (SP) and characterized by some spectroscopic techniques such as Fourier Transform Infrared, Nuclear Magnetic Resonance, X-ray diffraction, X-ray Dispersive Energy Spectroscopy, Scanning Electron Microscopy and cyclic voltammetry. As a fast application, after there the Ag+ was adsorbed by SP and in a second step, the resulting material was reacted with potassium hexacyanoferrate (III) (AgHSP). The cyclic voltammogram of the AgHSP showed two redox pairs with formal potentials (Eθ’) of Eθ’ (I) = 0.26 V and Eθ’ (II) = 0.71 V (v = 20 mV s−1, KNO3 1.00 mol L−1, pH 7.00) assigned to processes Ag0 / AgI and FeII (CN)6 / FeIII (CN)6, respectively. The analytical application of this new material (AgHSP) was tested in the rapid detection of acid ascorbic by strong electrocatalysis using graphite paste electrode (GPE). The limit of detection (LOD) obtained for this system was 7.034 × 10−5 mol L−1 with an excellent amperometric sensitivity of 0.0835 A / mol L−1.