Electrochemistry at cobalt(II)tetrasulfophthalocyaninemulti- walled carbon nanotubes modified glassy carbon electrode: a sensing platform for efficient suppression of ascorbic acid in the presence of epinephrine

Abstract

Electrochemistry of water-soluble cobalt(II) tetrasulfophthalocyanine (CoTSPc) electrodeposited on glassy carbon nanotube pre-modified with acid-functionalized multi-walled carbon nanotubes (MWCNT) is described. Both charge transfer resistances toward [Fe (CN)6]3−/4− redox probe and electrocatalytic responses toward epinephrine (EP) detection follow the trend: bare GCE<GCE-MWCNT<GCE-CoTSPc<GCE-MWCNTCoTSPc. EP analysis was then carried out in details using GCE-MWCNT-CoTSPc. The catalytic rate constant value kch=2.2×107 (mol cm−3)−1 s−1 was obtained from rotating disk electrode experiment. Interestingly, GCE-MWCNTCoTSPc efficiently suppressed the detection of ascorbic acid (the natural interference of neurotransmitters in physiological conditions) showing good sensitivity (0.132±0.003 A l mol−1), limit of detection (4.517×10−7 mol l−1), and quantification (15.056×10−7 mol l−1). In addition, GCE-MWCNT-CoTSPc was conveniently used to determine EP in epinephrine hydrochloric acid injection with recovery of 101.1±2.2%.