Abstract
The simultaneous determination of hydroquinone and catechol was conducted in aqueous and real samples by means of differential pulse voltammetry (DPV) using a glassy carbon electrode modified with Gold Nanoparticles (AuNP) and functionalized multiwalled carbon nanotubes by drop coating. A good response was obtained in the simultaneous determination of both isomers through standard addition to samples prepared with analytical grade water and multivariate calibration by partial least squares (PLS) in winery wastewater fortified with HQ and CT from 4.0 to 150.00 µM. A sensitivity of 0.154 µA µM−1 and 0.107 µA µM−1, and detection limits of 4.3 and 3.9 µM were found for hydroquinone and catechol, respectively. We verified the reliability of the developed method by simultaneously screening analytes in spiked tap water and industrial wastewater, achieving recoveries over 80%. In addition, this paper demonstrates the applicability of chemometric tools for the simultaneous quantification of both isomers in real matrices, obtaining prediction errors of lower than 10% in fortified wastewater.
Highlights
The determination of phenolic/polyphenolic compounds is a hot topic in the environmental, food and industrial fields [1]
Cyclic voltammetry (CV) was used to characterize and studied towards HQ using the different Multi-walled carbon nanotubes (MWCNT) in aqueous media
In order to obtain the highest current response, a previous pH study was performed in the range of 1.0–7.0 (Figure S1), indicating that the highest current for HQ oxidation is achieved at pH 2.0 for MWCNT-NH2 and MWCNTCOOH systems
Summary
The determination of phenolic/polyphenolic compounds is a hot topic in the environmental, food and industrial fields [1] Dihydroxybenzene compounds, such as hydroquinone (HQ) and catechol (CT), are toxic (100 μM in lymphocyte/human) and persistent in the environment [2,3,4,5]. The main difficulty in the simultaneous determination of both isomers lies mainly in the overlapping of the oxidation peaks, together with the loss of linearity in the voltammetric response due to competition between the two compounds for the electrode surface. Both problems can be solved by modifying the working electrode. In the last few years, many efforts have been devoted to developing modified electrodes able to increase the separation between both peaks together with the subsequent application of chemometric tools [6]
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