A sensitive electrochemical nanosensor based on iron oxide nanoparticles and multiwalled carbon nanotubes for simultaneous determination of benzoquinone and catechol in groundwater

ABSTRACT

Benzoquinone (BQ, 1,4-dihydroxybenzene) and catechol (CC, 1,2-dihydroxybenzene) are 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 proposes a novel sensor based on a multiwalled carbon nanotubes functionalised with carbonyls, and iron oxide nanoparticles (MWCNT-COOH/Fe₂O₃) for simultaneous determination of BQ and CC. The nanomaterials were characterised by Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Cyclic Voltammetry (CV). The electrochemical determination of BQ and CC has been studied using differential pulse voltammetry (DPV) technique on glassy carbon electrode (GCE) modified with MWCNT-COOH/Fe₂O₃ nanocomposite (MWCNT-COOH/Fe₂O₃/GCE). The developed new method under optimised experimental conditions was applied successfully for the simultaneous determination of BQ and CC in spiked underground water sample, pH 5.0 (Britton Robson – BR buffer). For DPV measurements, the following parameters were used after optimisation: E_initial = 0.0 V, E_final = 0.40 V; scan rate = 0.01 V s⁻¹ and pulse amplitude = 0.07 V. The linearity range of both analytes BQ and CC was 8–100 µmol L⁻¹ with limits of detection (DLs) of 3.46 µmol L⁻¹ and 1.52 µmol L⁻¹, respectively. Good average results of recovery (n = 3) were obtained in spiked environmental samples for BQ (sample 1: 98.16%; sample 2: 100.55%) and CC (sample 1: 97.44%; sample 2: 97.84%), with precision (relative standard deviation) of 4.5% and 5.6%, respectively.

KEYWORDS:

• Benzene derivatives
• iron oxide nanoparticles
• carbon nanotubes
• underground water
• glassy carbon electrode

Acknowledgments

The authors are grateful to CNPq (PQ 2017, Proc. 310664/2017-9), CAPES-PROCAD AM (Edital PROCAD AMAZÔNIA 2018 – Line 2; Number SCBA: 88887.200615/2018-00) and FAPEMA (Proc.N^o UNIVERSAL-01136/17) and ANP (Research Project PMQC/BIOPETRO, No 1.029/2016-ANP-007.639), for the financial support and fellowships received.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [PQ 2017, Proc. 310664/2017-9]; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [SCBA 450  88887.200615/2018-00]; Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão [Proc.No UNIVERSAL-01136/17]; Agência Nacional do Petróleo, Gás Natural e Biocombustíveis [1.029/2016-ANP-007.639].