Work

Chiral Carbon Paste Electrode with (+)-TCA/Graphene for Voltammetric Discrimination of Tryptophan Isomers

Year: 2025

Type: article

Abstract: We report for the first time the application of intrinsic chirality of RRRR (+) - (18-Crown-6) − 2, 3, 11, 12- tetra carboxylic acid ((+) TCA) along with graphene nanosheets (GN) in a chiral carbon paste electrode (CCPE) system for the voltammetric discrimination of tryptophan (TRY) isomers. Embedding (+) TCA in GN enhances rigidity and forms tripodal hydrogen bonds with amine groups of L-TRY and D-TRY, providing the sensor high stereoselectivity. Experimental and quantum chemical computational studies confirmed the stronger affinity of (+) TCA for L-TRY over D-TRY using the differential pulse voltammetry (DPV) and the counterpoise method. The stability constants (1:1 complex) of L-TRY and D-TRY with (+) TCA were 1191 M−1 and 588 M−1, respectively. Additionally, the peak potential difference (ΔEp = EL—ED) between enantiomers on CCPE was 129 mV. The lowest energy conformation of (+) TCA-L-TRY has a Gibbs free energy higher than (+) TCA-D-TRY by 7.08 kcal mol−1 (B3LYP) or 9.10 kcal mol−1 (M06–2X), indicating a preference for the L enantiomer. The detection limits for L-TRY and D-TRY are 0.023 μM and 0.075 μM, respectively, with a linear range from 1 μM to 120 μM. The sensor quantified TRY in blood serum and urine samples.

Source: Journal of The Electrochemical Society

DOI: 10.1149/1945-7111/adcfcb

Authors: Sharad S. Upadhyay, Mushtaq A. Dar, Nayan S. Gadhari, Devaraj Manoj, Pramod K. Kalambate

Language: English

Topic: Electrochemical sensors and biosensors

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $1,950

Funder: King Saud University

Award: G6870754892