Electrode Based on Nickel‐containing SBA‐15 for the Determination of Copper in Ethanol Biofuel

Abstract

A sensor based in a graphite–polyurethane composite electrode modified with the mesoporous nanostructured silica with hexagonal array of pores called Santa Barbara Amorphous type material (SBA‐15) containing nickel was built. The presence of Ni, incorporated during the synthesis of SBA‐15, resulted in an increase in sensitivity when compared to the other electrodes based on the unmodified SBA‐15. A procedure was proposed for the determination of Cu2+ in ethanol biofuel by square wave stripping voltammetry with linear response in concentration levels of 1.0×10−8 and 1.0×10−7 mol L−1, resulting in a limit of detection of 1.83×10−10 mol L−1 and precision (RSD) of 2.09 %.

Electrochemical Sensor Based on NiAlPO‐5 for Determination of Cu2+ in Ethanol Biofuel

“…However, the application of NiAlPO‐5 with Ni/Al ratios of 0.5 and 1.0 promoted evident improvements on the electrode responses in comparison with the others ratios (Figure ‐C and 3‐D). NiAlPO‐5 (0.5 and 1.0 ratios) exhibited characteristic peaks of oxidation referent to the Ni 2+ ‐Ni 3+ process in the zeolite structure, near 0.30 V as reported in literature . In addition, these voltammograms exhibited a oxidation peak of copper ion at −0.05 V indicating an irreversible behavior for this metal .…”

“…The influence of the modifiers AlPO‐5 and NiAlPO‐5 in the electrochemical response of electrodes for determination of Cu 2+ in ethanol was studied by SWSV technique using 8.0 mL of HCl 0.1 mol L −1 and 2.0 mL of supporting electrolyte in anhydrous ethanol media. In this comparison study, were used values of deposition potential (E dep ), deposition time (t dep ), pulse amplitude (Amp), step potential (E step ), frequency ( f ), previously optimized in literature .…”

“…As waited unmodified GPU electrode containing only graphite as conducting material does not present adequate properties to preconcentrate Cu 2+ in low levels of concentration on the electrode surface. Differently, AlPO‐5 material has some proprieties that can confer an improvement in preconcentration stage and consequently a better voltammetric response, even containing a neutral structure.…”

“…Based on these informations, a possible mechanism is proposed (Reactions: 1–3) for determination of Cu 2+ with the modified electrode by SWSV similarly as reported in the literature : …”

“…The influence of the modifiers AlPO-5 and NiAlPO-5 in the electrochemical response of electrodes for determination of Cu 2 + in ethanol was studied by SWSV technique using 8.0 mL of HCl 0.1 mol L À1 and 2.0 mL of supporting electrolyte in anhydrous ethanol media. In this comparison study, were used values of deposition potential (E dep ), deposition time (t dep ), pulse amplitude (Amp), step potential (E step ), frequency (f), previously optimized in literature [16]. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 According to the voltammograms ( Figure 4A), it is notable that the modification of graphite-polyurethane electrode promotes an improvement of the analytical signal of current.…”