A Simple and Rapid Electrochemical Determination of L-Tryptophan Based on Functionalized Carbon Black/Poly-L-Histidine Nanocomposite

In the present work, the functionalized carbon black/poly-l-histidine modified glassy carbon electrode (f-CB/PLH/GCE) was fabricated and applied for the amperometric determination of Try. The proposed modified electrode was prepared by non-hazardous, inexpensive, simple electro polymerization method. The successful formation of f-CB/PLH composite was scrutinized by field-emission scanning electron microscopy, transmission electron microscopy, optical microscope, energy dispersive X-ray spectroscopy, Fourier transform infra-red spectroscopy, Raman spectroscopy and electrochemical impendence spectroscopy. Besides, the electrocatalytic activity of the f-CB/PLH composite was examined by cyclic voltammetry and amperometric techniques. Remarkably, the wide linear range responses from 0.025–124.98 μM with the lowest detection limit 0.008 μM and an appreciable sensitivity of 1.126 μA mM −1 cm −2 was obtained. In addition, f-CB/PLH/GCE exhibits the good selectivity in presence of various inorganic, biological and co-existing interfering compounds. Furthermore, the practical feasibility of the sensor electrode was demonstrated in milk and human urine samples.