A novel bio-electrochemical ascorbic acid sensor modified with Cu-4(OH)(6)SO4 nanorods

Cu-4(OH)(6)SO4 (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 Cu-4(OH)(6)SO4 nanoparticles in fact possess an intrinsic electrocatalytic activity, which is explored as a biosensing material to oxidize L-ascorbic acid (AA). The Cu-4(OH)(6)SO4 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 mu A 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 Cu-4(OH)(6)SO4 nanomaterials promising for the development of effective electrochemical sensors for a wide range of potential applications in medicine, biotechnology and environmental chemistry.