A novel bio-electrochemical ascorbic acid sensor modified with Cu4(OH)6SO4nanorods

Abstract

Cu₄(OH)₆SO₄ (brochantite) is an undesirable oxidation product of copper-bearing sulfides, and it is seldom considered to be biologically and electrochemically active. In this paper, we report that Cu₄(OH)₆SO₄ nanoparticles in fact possess an intrinsic electrocatalytic activity, which is explored as a biosensing material to oxidize L-ascorbic acid (AA). The Cu₄(OH)₆SO₄ nanorod modified biosensor exhibits excellent performance for the determination of L-ascorbic acid with a response time of less than 8 s, a linear range between 0.017 and 6 mM, and a sensitivity of 17.53 μA mM⁻¹. A high selectivity towards the oxidation of AA in the presence of dopamine (DA) and acetyl aminophenol (AP) is also observed at their maximum physiological concentrations. The good analytical performance and long-term stability, low cost and straightforward fabrication method made the Cu₄(OH)₆SO₄ nanomaterials promising for the development of effective electrochemical sensors for a wide range of potential applications in medicine, biotechnology and environmental chemistry.