Direct electrosynthesis of graphene oxide nanoparticles on the pencil lead electrode surface: Application to electroanalysis determination of L-tyrosine

l-Tyrosine (L-Tyr) is an essential amino acid that extensively exists in human body. It is a vital precursor for neurotransmitters and hormone in mammalian animals such as dopamine and norepinephrine, and also plays a pivotal role in food processingindustry, pharmaceutical field and agricultural industry as well [1]. Tyr and Tryptophane are vital constituents of proteins, which are indispensable in human nutrition for establishing and maintaining a positive nitrogen balance. These compounds are sometimes added to dietary and food products and to pharmaceutical formulations due to the scarcely present in vegetables. For simple, sensitive and less expensive detection of Tyr and Trp, the methods based on electroanalysis might be the most notable due to their electrochemical activity [2]. In this research, an electrochemical sensor based on graphenaized pencil lead electrode for sensitive determination of l-tyrosine (L-Tyr) was presented here. Pencil lead electrode was graphenized by applying DC potantial in acidic media. Electron transfer behavior of graphenized pencil lead electrode was investigated in 5 mM K3[Fe(CN)6]/K4[Fe(CN)6] solution using cyclic voltammetry. The electrochemical response of modified electrodes toward L-Tyr was investigated by cyclic voltammetry (CV), amperometry in detail .To further study the practical applicability of the fabricated sensor, it was applied to detect real samples and the received results were satisfactory. X-ray photoelectron spectroscopy and SEM, and electrochemical techniques were used for characterization of the electrode surface.