Facile one-step activated glassy carbon electrode for sensitive tryptophan sensing in yogurt

Authors

• SEVİLAY ERDOĞAN KABLAN, Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Ankara, TurkiyeFollow
• AHMET ÇETİNKAYA, Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Ankara, Turkiye; Department of Analytical Chemistry, Gülhane Faculty of Pharmacy, University of Health Sciences, Ankara, TurkiyeFollow
• SİBEL ÖZKAN, Department of Analytical Chemistry, Faculty of Pharmacy, Ankara University, Ankara, TurkiyeFollow
• EMİRHAN NEMUTLU, Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Ankara, TurkiyeFollow

Abstract

Activation of glassy carbon electrodes (GCEs) in tailored solution environments introduces oxygenated surface functionalities such as hydroxyl, carboxyl, and quinone groups. These modifications enhance electron‐transfer kinetics and strengthen interactions with target analytes, thereby improving electrochemical sensitivity. In this study, square-wave voltammetry was used, and the most suitable supporting electrolyte for tryptophan (TRP) analysis was a pH 3 Britton–Robinson buffer. The cyclic voltammetry potential range and number of cycles for the Act-GCE were obtained as 0–1.5 V and seven cycles, respectively. The activated electrode exhibited excellent analytical performance, with a linear response for TRP over 0.20–6.28 μM, a detection limit of 0.06 μM, and a quantification limit of 0.20 μM. Its practical applicability was confirmed by recovery tests of yogurt samples, demonstrating accurate and reliable real-sample analysis. Scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy were used for both electrochemical and morphological characterization. For TRP analysis of yogurt samples, the square wave voltammetry results obtained with the Act-GCE showed strong agreement with liquid chromatography-mass spectrometry data, and a statistical evaluation confirmed no significant difference between the two methods (p = 0.17). Moreover, the electrode material was used reliably to determine TRP in a yogurt sample with excellent recovery.

Author ORCID Identifier

SEVİLAY ERDOĞAN KABLAN: 0000-0002-6503-0142

AHMET ÇETİNKAYA: 0000-0001-5014-0907

SİBEL ÖZKAN: 0000-0001-7494-3077

EMİRHAN NEMUTLU: 0000-0002-7337-6215

DOI

10.55730/1300-0527.3913

Keywords

Tryptophan, square wave voltammetry, activated glassy carbon electrode, electrochemical determination, LC-MS/MS analysis, yogurt

First Page

481

Last Page

490

Publisher

The Scientific and Technological Research Council of Türkiye (TÜBİTAK)

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

ERDOĞAN KABLAN, S, ÇETİNKAYA, A, ÖZKAN, S, & NEMUTLU, E (2026). Facile one-step activated glassy carbon electrode for sensitive tryptophan sensing in yogurt. Turkish Journal of Chemistry 50 (5): 481-490. https://doi.org/10.55730/1300-0527.3913