Eletrodo de carbono vítreo modificado com nanotubos de carbono e nanopartículas de óxido de ferro na análise simultânea de benzoquinona e catecol em água subterrânea

Abstract

Benzoquinone (BQ, 1,4-dihydroxybenzene) and catechol (CC, 1,2-dihydroxybenzene) are byproduct derived from benzene, and considered as emerging microcontaminants due to their persistent toxicity for plants and animals. Therefore, it is of great importance to monitor these contaminants in groundwater. This work propose a procedure to determine BQ and CC in undergroundwater of fuel stations with a voltammetric sensor based in a multiwalled carbon nanotubes functionalized with carbonyls and iron oxide nanoparticles (NTCPM- COOH/Fe2O3) in 0.1 M Britton Robson (BR) buffer solution, pH 5.0, by cyclic voltammetric (CV) and differential pulse voltammetry (DPV) techniques. The proposed sensor presented an excellent electrochemical performance for the oxidation of BQ and CC. Under optimized experimental conditions, the anodic peak currents for the individual determination of the analytes were linear in the 4 to 36 μmol L-1 concentration range for both BQ and CC, with limits of detection (DL) of 0.99 μmol L-1 and 0.72 μmol L-1, respectively. Additionally, the anodic peak currents for the simultaneous determination were linear in the range of 12 to 70 μmol L-1, for both analytes. Through the calibration curves it were calculated their DL: 1.56 (BQ) and 0.97 μmol L-1 (CC). Good results were obtained in terms of recovery (BQ: 99.08 %; CC: 96.62% ), precision (standard deviadion for BQ: 4.52 % and for CC: 5.60 %). These results indicate that this method is sufficiently suitable as an alternative method for determining BQ and CC content in underground water.