Ti-Catalyst Biomimetic Sensor for the Detection of Nitroaromatic Pollutants

Anal Chem. 2019 Feb 19;91(4):2797-2804. doi: 10.1021/acs.analchem.8b04671. Epub 2019 Feb 5.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aniline Compounds / analysis*
  • Biomimetics / methods
  • Catalysis
  • Dinitrobenzenes / analysis*
  • Electrochemical Techniques / methods
  • Electrodes
  • Environmental Pollutants / analysis*
  • Fluorocarbon Polymers / chemistry
  • Limit of Detection
  • Nitrophenols / analysis*
  • Titanium / chemistry*

Substances

  • Aniline Compounds
  • Dinitrobenzenes
  • Environmental Pollutants
  • Fluorocarbon Polymers
  • Nitrophenols
  • nitroaniline
  • perfluorosulfonic acid
  • Titanium