Printex 6L Carbon Nanoballs used in Electrochemical Sensors for Simultaneous Detection of Emerging Pollutants Hydroquinone and Paracetamol

We report the use of Printex 6L Carbon nanoballs (CNB) as electrode material for electrochemical detection of hydroquinone (HQ) and paracetamol (PARA). Nanoballs with diameters between 20 and 25 nm are amorphous, impurity-free according to energy-dispersive X-ray spectroscopy, and formed homogeneous films on glassy carbon (GC) electrodes. Their conductive behavior was confirmed with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which could be exploited in differential pulse voltammetry (DPV) to detect HQ and PARA at low overpotential (67 and 341 mV vs. Ag/AgCl for HQ and PARA, respectively) between 8.0 x 10(-8) and 2.3 x 10(-4) mol L-1. The limit of detection for these GC/CNB sensors was 13.0 and 8.0 x 10(-9) mol L-1 for HQ and PARA, respectively, being competitive with other devices made with carbonaceous materials. In spite of their simplicity, the sensors were also stable, reproducible and robust against typical interferents in biological fluids such as nitrite, sulfite, the antibiotic amoxicillin, sodium dodecyl sulfate (SDS) and humic substances. Experiments with natural waters from a creek indicated that electrochemical sensing of HQ and PARA with GC/CNB is as efficient as standard chromatography. Because CNB are much simpler and cheaper to produce than other carbon materials, e.g. graphene and nanotubes, their use may be advantageous in other electroanalytical applications. (C) 2017 Elsevier B.V. All rights reserved. (AU)