Sensitive Electrochemical Detection of L-Tryptophan Using a Glassy Carbon Electrode Modified with Pectin Extracted from Arthrocnemum Indicum Leaves

Pectin from Arthrocnemum indicum leaves (PAI) extracted from plants, harvested in the Tunisian Sahel, was used for the first time as a sensitive matrix for the design of an electrochemical sensor of L-tryptophan via differential pulse voltammetry (DPV). A glassy carbon electrode (GCE) was modified by a PAI layer through simple adsorption, leading to a DPV signal of L-tryptophan that was increased by a factor of 15. The PAI-modified electrode exhibited a good analytical performance towards the detection of L-tryptophan with a wide linear range between 9.10-5 mM to 2.10-2 mM, a detection limit of 0.09 mu M, and a sensitivity of 90.15 mu A. mM-1. Compared to other reported electrochemical sensors, PAI/GCE presents a lower detection limit, even without the use of nanomaterials. In addition, the PAI/GCE showed good reproducibility and good selectivity towards the determination of L-tryptophan versus other amino acids, uric acid, and ascorbic acid, making it suitable for the determination of L-tryptophan in biological fluids.