Ruthenium Red-functionalized sol-gel and multi-walled carbon nanotubes for electrochemical simultaneous detection of three dihydroxybenzene isomers

Abstract

In this proof-of-concept study, sol–gel was functionalized with Ruthenium Red (RR) using 3-glycidoxypropyl trimethoxysilane as the coupling agent and multi-walled carbon nanotubes (MWCNTs) and characterized with FT-IR, SEM and TEM as well as electrochemical techniques. The functionalized sol–gel (fSG) nanocomposite was used for the modification of a graphite paste electrode (GPE/fSGRR-MWCNTs) for the speciation of dihydroxybenzene compounds, hydroquinone (HQ), catechol (CC), and resorcinol (RS) which are known as hazardous water pollutants. The DPV measurements were performed in phosphate buffer solution at pH 5.0 from −0.2 to 1.0 V vs. Ag/AgCl. The nanocomposite-modified electrode displayed stable and continuous three well-separated oxidation peaks at 0.20, 0.30 and 0.72 V for HQ, CC, and RS, respectively. The limit-of-detection (LOD) was determined to be 0.049, 0.008 and 0.015 μM for HQ, CC, and RS, respectively. The modified GPE/fSGRR-MWCNTs showed good stability, reproducibility, sensitivity, and selectivity properties to determine all three compounds. The electrochemical performance of the GPE/fSGRR-MWCNT has been evaluated for simultaneous determination of dihydroxybenzene isomers in creek water, residential wastewater, and commercial hair dye, with satisfactory recoveries between 95 and 104%. This modified GPE/fSGRR-MWCNTs showed better stability, reproducibility, sensitivity, and selectivity properties to determine all three compounds when compared with the similar modified electrodes recently reported in the literature. Therefore, this novel RR-containing nanocomposite-modified sensor can be a promising pre-screening tool for the inexpensive and rapid detection of HQ, CC, and RS in on-field environmental studies.