The electrochemical investigation of carboxamide-PEG2-biotin-CoPc using composite MWCNTs on modified GCE: the sensitive detections for glucose and hydrogen peroxide

Abstract

The electroanalytical study of a synthesized novel tetra-cobalt(II) carboxamide-PEG₂-biotin phthalocyanine (CoTPEG₂BAPc) composite with MWCNTs to create a biosensor with a high response to glucose in the presence of H₂O₂. The glucose biosensor can be easily detected by casting onto GCE, and and it displays intrinsic electrocatalytic ability for the enzymatic oxidation and reduction of glucose and H₂O₂, showing higher catalytic activity than that of a bulk CoTPEG₂BAPc electrode. Under optimal conditions, the biosensor shows a wide linear response to glucose (CV: 2–16; DPV: 2–22; CA: 5–50 μmol) and H₂O₂ (CV: 5–25; DPV: 2–22; CA: 5–50 μmol), good sensitivity towards glucose (CV: 0.947; DPV: 1.978; CA: 0.101 μA μM⁻¹ cm⁻²) and H₂O₂ (CV: 1.250; DPV: 1.888; CA: 0.162 μA μM⁻¹ cm⁻²), and a stable long-term life and LOD for glucose (CV: 0.33; DPV: 2; CA: 12.5 μmol L⁻¹) and H₂O₂ (CV: 1.5; DPV: 5; CA: 10 μmol L⁻¹). The amperometry selectivity studies involving different biomolecules, including AA, DA, UA, L-cysteine, and glycine, show that they do not affect glucose and H₂O₂ determination. Our present work exhibits very attractive and practical performance for biosensor applications.