Detection of pharmaceuticals and anions in water using carbon-based electrodes

Abstract

Important resource for supporting life in all ecosystems, water is daily affected by the anthropogenic pressures which will impose serious repercussions over its quality. For this reason, at global level several regulations were adopted in order to reduce the pollution, but also to improve the quality of water. With all this, in the last years, the occurrence in water of a new class of emerging pollutants - pharmaceuticals was revealed by several studies. Their detection mainly through chromatographic methods is quite laborious and timeconsuming. In this context, an alternative to classical methods is developed by employing the applications of electroanalysis. The aim of this study consisted of the development of fast and low-cost individual/simultaneous procedure for pharmaceuticals detection in aqueous solutions using electrochemical techniques and carbon-based electrode materials. In addition, similar procedures for the detection of specific anions in water by using the same carbon-based electrode materials were developed. Several types of composite electrodes based on carbon nanofiber and carbon nanotube were prepared. The morphostructural, electrical and electrochemical characterization of these electrodes showed a great potential for electroanalytical applications. The electrochemical behaviour of each target analyte on the composite electrodes was studied by cyclic voltammetry in the presence of various concentration ranges. Based on the best sensitivity and lowest potential detection value, it was selected the electrode materials for voltammetric/amperometric detection schemes. The individual/simultaneous detection protocols for target pharmaceutical compounds, i.e., fluoxetine, naproxen, tetracycline, and for sulfide and nitrite anions were developed in relation with the electrode material and the electrochemical technique. The obtained results are very promising and constitute the first step for developing in-situ or infield detection applications.