complex based on Ntripodal ligand immobilized in a Nafion® film for biomimetic detection of catechols: Application to dopamine. Electrochimica Acta, Elsevier, 2016, 221, pp.80-85 AbstractA complex based on bis-pyrazolyl N-tripodal ligand known to present a good catalytic activity for the oxidation of 3,5-di-tert-butylcatechol is used to prepare a novel biomimetic sensor for the determination of catechol derivatives. The modified electrode prepared by encapsulation of the complex in a Nafion ® film leads to an electrochemical signal 4.4 times higher than with a glassy carbon electrode for dopamine detection in pH 7 medium. After optimization of the conditions used to immobilize the catalyst on the electrode surface, a calibration curve was obtained with linearity in the range of 30 to 320 mol L -1 and a detection limit of 8 mol L -1 .The sensor was not affected by ascorbic acid and uric acid in similar concentrations to dopamine and its electrochemical response was stable after 40 determinations. The biomimetic sensor can also be used for the detection of other catechol derivatives.

An electrode modified by a Ti complex in Nafion ® was used in the electrochemical detection of nitroaromatic compounds (NACs). The catalyst reduces nitroaromatic groups by a 6-electron process and with a high apparent rate constant k 1 that was estimated to be at least 19000 mol -1 L s -1 by simulation of the first step of the cathodic reduction of 4-nitrophenylacetic acid used as model molecule. The modified electrode was prepared and optimized in terms of Nafion ® and catalyst concentrations. In the chosen analytical medium, the Ti catalyst-containing electrode shows a good stability in the presence of nitro species. A standard deviation around 15% was calculated on the analysis performed with 28 different modified electrodes, which could be expected for a drop-coating process. We show that the modified electrode detects several nitroaromatic compounds such as nitrophenols, mononitroaniline and dinitrotoluene with detection limits ranging from 1 to 9 × 10 -4 g L -1 (0.2-5.1 × 10 -6 mol L -1 ). As an interesting feature, the sensor exhibits a good selectivity towards NACs detection since titanocene did not catalyze the reduction of nitroaliphatic compounds.