Development of electrochemical sensor based on nanoparticles for the determination of various food additives and vitamins

The aim of the present thesis is development of an electrochemical sensor based on nanoceria (CeO2) particles for the determination of various food additives (food colorants) and vitamins. For this purpose firstly the carbon paste prepared by mixing graphite powder, CeO2NP and non-electroactive binder liquid (such as mineral oils) was placed on the body polyetheretherketone electrode body. The prepared electrodes was called as nanoceria modified carbon paste electrode (CeO2NP/ MCPE). The surface morphology of CeO2NP/ MCPE was examined via the Scanning Electron Microscope and the EDX analysis was performed. The electron transfer properties of CeO2NP/ MCPE were studied by electrochemical impedance spectroscopy and cyclic voltammetry techniques. The obtained results were compared with those obtained at unmodified carbon paste electrode (CPE). Besides, the amount of CeO2NP in the paste composition was optimized. In the second part of the study, electrochemical oxidation behaviours of the various vitamins (ascorbic acid, vitamin B2 and vitamin B9) and the various food colorants (tartrazine, sunset yellow and brilliant blue) were studied by using CeO2NP/ MCPE. For each species linear working range and detection and limits were determined. The effects of potential interfering substances present in real samples on the response were also studied. Finally, analytical applicability of the prepared sensor was investigated and the recovery values (%) were calculated.