Pharmaceuticals contaminants in waters exhibit a significant threat on the human health and the ecosystem quality. This research demonstrates the utility of a silver-doped zeolite-modified carbon nanofiber-epoxy (AgZ-CNF) prepared by two-roll mill method in development of the fast methodology for the detection of fluoxetine (FXT) in the aqueous solution. The results showed the role of zeolite that improved the sensitivity and the limit of detection of FXT resulted to the possibility to propose a specific preconcentration-based detection protocol. The silver contributed to decreasing the anodic over potential for FXT oxidation and hence, for FXT detection. The best sensitivity of 2.007 μA μM-1 and lowest limit of detection of 19 nM are were obtained for preconcentration-cyclic voltammetry based scheme, which is very promising for the detection of FXT at trace levels. Also, the chronoamperometry operated at 0.350 V/SCE specific to silver involving and +1.1V/SCE characteristics to the carbon nanofiber, allowed FXT detection in the aqueous solution. The long life time and the stable response for FXT detection was found for AgZ-CNF composite electrode, which suggests its practical utility in FXT determination in the real water sources.

In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP) and diclofenac (DCF) in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF) electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV) was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA) and multiple-pulsed amperometry (MPA). This electrode exhibited the possibility to selectively detect IBP and DCF by simple switching the detection potential using CA. However, the MPA operated under optimum working conditions of four potential levels selected based on CV shape in relation to the potential value, pulse time, and potential level number, and order allowed the selective/simultaneous detection of IBP and DCF characterized by the enhanced detection performance. For this application, the HKUST-CNF electrode exhibited a good stability and reproducibility of the results was achieved.