Dopamine determination using a biosensor based on multiwall carbon nanotubes paste and burley tobacco-peroxidase

Abstract

Abstract: The development of an enzymatic biosensor for dopamine determination based on multiwall carbonnanotubes (MWCNTs) and peroxidase obtained from the crude extract of burley tobacco (Nicotiana tabacum L.)was proposed. Peroxidase catalyzes the oxidation of dopamine to dopamine quinone. The influence on theresponse of analytical parameters of biosensors such as enzyme concentration, dopamine concentration, pH, andphosphate buffer solution concentration were investigated. The analytical parameters obtained, including sensitivity,linearity, and stability, were investigated. The proposed method for dopamine determination presented good selectivityeven in the presence of uric acid and ascorbic acid. The sensor presented a higher response for dopamine in0.010 M phosphate buffer at pH 6.50, with an applied potential of -0.15 V. The detection limit of the electrodewas 2.7×10 −6 M (S/N = 3) and the relative standard deviation of the measurements, which were repeated 10times using 5.0×10 −2