Ti-Catalyst Biomimetic Sensor for the Detection of Nitroaromatic Pollutants

Alizée Lemaire (1) , Philippe Hapiot (1) , Florence Geneste (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

An electrode modified by a Ti complex in Nafion was used in the electrochemical detection of nitroaromatic compounds (NACs). The catalyst reduced nitroaromatic groups by a six-electron process with a high apparent rate constant, k1, which was estimated to be at least 19 000 mol–1 L s–1 by simulation of the first step of the cathodic reduction of 4-nitrophenylacetic acid, which was 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 showed 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 × 10–4 to 9 × 10–4 g L–1 (0.2 × 10–6 to 5.1 × 10–6 mol L–1). As an interesting feature, the sensor exhibits good selectivity toward NAC detection because titanocene does not catalyze the reduction of nitroaliphatic compounds.

Keywords: NAC index; Biomimetic sensor; Nafion; Titanocene; Nitroaromatic pollutants

Domains: Chemical Sciences; Analytical chemistry; Chemical Sciences; Other; Environmental Sciences; Environmental Engineering

Alizée Lemaire, Philippe Hapiot, Florence Geneste. Ti-Catalyst Biomimetic Sensor for the Detection of Nitroaromatic Pollutants. Analytical Chemistry, 2019, 91 (4), pp.2797-2804. ⟨10.1021/acs.analchem.8b04671⟩. ⟨hal-02015559⟩