Voltammetric determination of tryptophan at graphitic carbon nitride modified carbon paste electrode

Abstract

Herein, we reported carbon paste electrode modified with graphitic carbon nitride (g–C3N4–CPE) to determine of tryptophan (Trp) using voltametric techniques. Various spectroscopic and electrochemical techniques were used to characterize the as-synthesized g-C3N4 and the assembled electrodes. The transfer coefficient, rate constant and the diffusion coefficient of Trp in this system were found to be 0.28, 1.9 × 104 M−1s−1 and 3.2 × 10−5 cm2s−1, respectively. The linear range was obtained for the detection of Trp using LSV is from 0.1 μM to 120 μM at pH 5. The limit of detection (LOD) (3σ/m) was 0.085 μM. The demonstrated modified CPE was also effectively used for the detection of Trp in milk with percentage recovery of 98 %–105.2 %. Furthermore, the modified CPE exhibited good repeatability, reproducibility and appropriate selectivity.