Electropolymerization of diaminofluorene and its electrochemical properties

AbstractPoly 2,7-diaminofluorene (PDAF)/Au modified electrode was prepared using 2,7-diamino fluorene (DAF) dissolved in acetonitrile (ACN) containing 0.1M LiClO4 using consecutive multisweep cyclic voltammetry (CV) and controlled potential electrolysis (CPE) techniques. Factors affecting the film formation, such as limits of potential cycling, sweep rate, number of sweeping cycles, monomer concentration, and also polymerization techniques were examined in detail. It was found that the optimum conditions, using a potentiodynamic technique on Au electrode as the working electrode, are by sweeping the potential between –200mV and 800mV at a sweep rate of 50mV/s for 10 cycles using 5mM DAF monomer solution. The obtained modified electrode was active only in acidic aqueous solutions (pH range from 0 to 2) and its activity was found to be pH dependent. PDAF was isolated and characterized using UV–vis, 1HNMR and SEM analyses. The electrical conductivity was found to be 1.5×10−5Scm−1. An electropolymerization mechanism was proposed and discussed based on the obtained experimental data and molecular orbital calculations. The obtained modified electrode has been found to improve the electrochemical reversibility and decrease the overpotential of hydroquinone. PDAF/Au was stable chemically and electrochemically both in aqueous and organic solutions, making it an excellent candidate for sensing and/ or electrocatalytic applications

Inactivation of Listeria monocytogenes in raw and hot smoked trout fillets by high hydrostatic pressure processing combined with liquid smoke and freezing

High hydrostatic pressure (HHP; 200 MPa for 15 min), liquid smoke (0.50%, v/v) and freezing (−80 °C, overnight) was used to eliminate Listeria monocytogenes in BHI broth, raw and smoked trout. The bactericidal effect of liquid smoke solutions (L9 and G6), HHP and their combinations was evaluated against L. monocytogenes LO28, EGD-e and 10403S and further continued with the most resistant strain (10403S) to the combined treatment. For first time, a synergistic effect of liquid smoke and HHP was observed and was further enhanced by freezing prior to HHP. The effect of HHP and liquid smoke, prior to freezing was highest in BHI compared to raw and smoked trout. A major synergistic effect of HHP, liquid smoke and freezing was observed, reaching a 5.48 or 1.93 log CFU/g reduction when smoked or raw trout was used respectively. Furthermore, high injury levels occurred, among treatments reaching up to 55.98%