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An electrochemical sensor based on molecularly imprinted polymer (MIP) film for dodecyl gallate detection at the surface of a glassy carbon electrode (GCE) was proposed in this paper. The GCE was modified with f-MWCNT and the MIP synthesis was performed in situ by means of electropolymerization using ortho-phenylenediamine as the monomer. The stepwise preparation of the MIP and NIP (non-imprinted polymer) was characterized electrochemically by means of cyclic and square wave voltammetry employing ferrocyanide/ferricyanide as a redox probe. The selective capacity performance of the MIP and its imprinted effect to the template molecule (analyte) was compared to the NIP. They were also characterized by scanning electron microscopy technique (SEM). The analytical performance of the MIP sensor performed using square wave voltammetry showed linear range from 0.50 to 8.0 × 10 −9 mol L −1 , with a correlation coefficient of 0.9921. The sensor presented detection and quantification limit of 0.22 × 10 −9 and 0.67 × 10 −9 mol L −1 , respectively. The apparent dissociation constant (K D) calculated was of 1.26 × 10 −4 mol L −1 and 5.27 × 10 −1 mol L −1 for the MIP and NIP respectively.

The scientific question addressed in this work is: what hides beneath first order kinetic constant k (s −1) measured for hybridization of a DNA target on a biosensor surface. Kinetics hybridization curves were established with a 27 MHz quartz microbalance (9 MHz, third harmonic) biosensor, constituted of a 20base probe monolayer deposited on a gold covered quartz surface. Kinetics analysis, by a known twostep adsorption-hybridization mechanism, is well appropriate to fit properly hybridization kinetics curves, for complementary 20-base to 40-base targets over two concentration decades. It was found that the K 1 (M −1) adsorption constant, relevant to the first step, concerns an equilibrium between non hybridized targets and hybridized pre-complex and increases with DNA target length. It was established that k 2 (s −1), relevant to irreversible formation of a stable duplex, varies in an opposite way to K 1 with DNA target length.