Copper nanoparticles and carbon nanotubes-based electrochemical sensing system for fast identification of tricresyl-phosphate in aqueous samples and air

An electrochemical method has been developed for the determination of tricresyl phosphate (TCP) in aqueous media and air. Although TCP is not an electroactive species, conversion of TCP by acid hydrolysis to cresol enables electrochemical detection techniques to be exploited. Amperometric detection was performed using glassy carbon electrode (GC), glassy carbon electrode covered with multiwall carbon nanotubes (GC/MWNTs), and glassy carbon electrode covered with multiwall carbon nanotubes and copper (GC/MWNTs/Cu). It was demonstrated that the most favorable was GC/MWNT/Cu electrode since the electrodeposition of copper onto the MWNT led to enhancement of the analytical response and the possibility of detecting cresol at a low potential (0.54 V versus Ag/AgCl) and higher currents when compared with other electrodes. Scanning electron microscopy with chemical analysis by energy dispersive X-ray techniques was used for the characterization of the distribution of the Cu nanoparticles on the electrode surface. The linear range of cresol detection was 10–160 μM with detection limit of 0.6 μM. The method demonstrates an interesting and desirable alternative for TCP determinations and was used for the determination of TCP in aqueous media and three different concentrations of air samples.