Macrocyclic Compounds Based Chemically Modified Electrodes for Voltammetric Determination of L-Tryptophan Using Electrocatalytic Oxidation

The electrochemical behavior of L-tryptophan is studied at carbon paste electrode and electrodes modified with different macrocyclic compounds of which Dibenzo-18-crown-6 (DB18C6) showed better response for L-tryptophan at + 0.95 V vs. Ag/AgCl. Use of Ni2+ ions as electrocatalyst shows a further enhancement in peak current leading to a linear range of 1.96 × 10−6 − 1.01 × 10−3 M and a detection limit of 9.79 × 10−8 M by differential pulse voltammetry. Electrochemical impedance diagnosis reveals that L-tryptophan oxidation is kinetically facile on DB18C6 modified electrode. The modified electrode is used for L-tryptophan determination in real samples.