Electrochemical biosensing of promethazine using glassy carbon electrodes modified with bamboo type multi-walled carbon nanotubes dispersed in double-stranded calf-thymus DNA

EMILIANO N. PRIMO,; OVIEDO M B; SANCHEZ CRISTIAN; MARÍA D. RUBIANES ; RIVAS G. A.

BIOELECTROCHEMISTRY

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2014 vol. 99 p. 8 - 16

1567-5394

We report the quantification of promethazine (PMZ) using glassy carbon electrodes (GCE) modified with bamboo-like multi-walled carbon nanotubes (bCNT) dispersed in double stranded calf-thymus DNA (dsDNA) (GCE/bCNT-dsDNA). Cyclic voltammetry measurements demonstrated that PMZ presents a thin film-confined redox behavior at GCE/bCNT-dsDNA, opposite to the irreversibly-adsorbed behavior obtained at GCE modified with bCNT dispersed in ethanol (GCE/bCNT). Differential pulse voltammetry-adsorptive stripping with medium exchange experiments performed with GCE/bCNT-dsDNA and GCE modified with bCNTs dispersed in single-stranded calf-thymus DNA (ssDNA) confirmed that the interaction between PMZ and bCNT-dsDNA is mainly hydrophobic. These differences are due to the intercalation of PMZ within the dsDNA that supports the bCNTs, as evidenced from the bathochromic displacement of UV-Vis absorption spectra of PMZ and quantum dynamics calculations at DFTB level. The efficient accumulation of PMZ at GCE/bCNT-dsDNA made possible its sensitive quantification at nanomolar levels (sensitivity: (3.50±0.05)×108μA·cm-2·M-1 and detection limit: 23nM). The biosensor was successfully used for the determination of PMZ in a pharmaceutical product with excellent correlation. © 2014 Elsevier B.V.