Alumina micro powder

Glassy carbon electrode (3 mm diameter) was purchased from CH Instrument USA. Polishing pads were obtained from Buehler, IL, USA and Alumina micro powder (1.0, 0.3 and 0.05 μm alumina slurries) was used for polishing the Glassy carbon electrode (GCE). Pristine multi-walled carbon nanotubes (95% purity, 10–20 nm); Iron(III) chloride (FeCl₃), zinc nitrate hexahydrate (Zn(NO₃)₂ · 6H₂O), 29H,31H-Phthalocyanine (29H,31H-Pc), 2,3-Naphthalocyanine (2,3-Nc), dopamine hydrochloride, ascorbic acid and other reagents are of analytical grade and obtained from Sigma-Aldrich, Merck chemicals and LABCHEM respectively. Ultra-pure water of resistivity 18.2 MΩ was obtained from a Milli-Q Water System (Millipore Corp., Bedford, MA, USA) and was used throughout for the preparation of solutions. A phosphate buffer solution (PBS) of 7.0 was prepared with appropriate amounts of NaH₂PO₄ · 2H₂O, Na₂HPO₄ · 2H₂O, and H₃PO₄, and adjusted with 0.1 M H₃PO₄ or NaOH. Prepared solutions were purged with pure nitrogen to eliminate oxygen and prevent any form of external oxidation during every electrochemical experiment.

Glassy carbon electrode (3 mm diameter) was purchased from CH Instrument USA. Polishing pads were obtained from Buehler, IL, USA and Alumina micro powder (1.0, 0.3 and 0.05 μm alumina slurries) was used for polishing the Glassy carbon electrode (GCE). Pristine multi-walled carbon nanotubes (95% purity, 10–20 nm); Iron(III) chloride (FeCl₃), zinc nitrate hexahydrate (Zn(NO₃)₂.6H₂O), 29H,31H-Phthalocyanine (Pc), 2,3-Naphthalocyanine (Nc), (±)-Epinephrine hydrochloride, L-Norepinephrine hydrochloride, dopamine hydrochloride, ascorbic acid and other reagents are of analytical grade and obtained from Sigma-Aldrich, Merck chemicals and LABCHEM respectively. Ultra-pure water of resistivity 18.2 MΩ was obtained from a Milli-Q Water System (Millipore Corp., Bedford, MA, USA) and was used throughout for the preparation of solutions. A phosphate buffer solution (PBS) of 7.0 was prepared with appropriate amounts of NaH₂PO₄.2H₂O, Na₂HPO₄.2H₂O, and H₃PO₄, and adjusted with 0.1 M H₃PO₄ or NaOH. Prepared solutions were purged with pure nitrogen to eliminate oxygen and prevent any form of external oxidation during every electrochemical experiment.