Electrochemical analysis of L-Tryptophan at highly sensitive poly(Glycine) modified carbon nanotube paste sensor

In the present work, we developed poly(Glycine) modified carbon nanotube paste electrode (PGMCNTPE) as a biosensor for eliciting the electrooxidation of L-Tryptophan (TRP). The surface of the sensors was characterised by Field emission scanning electron microscopy (FE-SEM) and Electrochemical impedence spectroscopy (EIS). The analysis of TRP was succeeded at the surface of PGMCNTPE for their high electrical conductivity and electrostatic interaction, that amplified the oxidation peak current by 8 fold in cyclic voltammetry (CV) and by 12 fold in differential pulse voltammetry (DPV) as compared to unmodified electrode. The activity of sensor on TRP was manifested to be irreversible reaction proceeding with the transfer of 2e− and 2H+ and adsorption controlled. Under the optimal state, it was noteworthy that the execution of the sensor revealed to have a low detection limit of 0.42 μM on a broad linear range of 20 μM to 100 μM. Lastly, the determination of TRP was exploited successfully in the pharmaceutical supplement.