Thymine-modified pencil graphite electrode for the sensitive determination of dopamine in rat brain samples: Voltammetric analysis validated by LC–MS/MS
Microchemical Journal, vol.227, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 227
- Publication Date: 2026
- Doi Number: 10.1016/j.microc.2026.118719
- Journal Name: Microchemical Journal
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Chemical Abstracts Core, Chimica, Index Islamicus, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Keywords: Dopamine, Liquid chromatography tandem mass spectrometry, Pencil graphite electrode, Rat brain sample, Sensor electrode, Square wave adsorptive stripping voltammetry
- Anadolu University Affiliated: Yes
Abstract
In this study, a thymine-modified pencil graphite electrode (THY/PGE) was used for the first time for the determination of dopamine (DA) by square wave adsorptive stripping voltammetry (SWAdSV), and the results were compared with those obtained by liquid chromatography tandem mass spectrometry (LC–MS/MS). THY/PGE modification was performed using cyclic voltammetry (CV) with 10 cycles at a scan rate of 0.1 V s−1 over the potential range from +0.4 to +1.5 V. The modification was characterized by CV, electrochemical impedance spectroscopy (EIS), and field–emission scanning electron microscopy (FE–SEM). pH optimization was performed using square wave voltammetry (SWV), and the optimal pH was determined to be 7.2 in phosphate buffer solution (PBS). Subsequently, SWV, SWAdSV, differential pulse voltammetry (DPV), and differential pulse adsorptive stripping voltammetry (DPAdSV) techniques were evaluated, and SWAdSV was selected as the most suitable, with optimal accumulation time of 60 s. SWAdSV showed a linear responses in the ranges of 0.001–0.1 mM and 0.025–0.75 μM, with LOD and LOQ values of 4.68 nM and 14.04 nM, respectively. In rat brain samples, recoveries at 5 μM and 10 μM were 101.60% and 98.20% for LC–MS/MS and 100.62% and 100.34% for SWAdSV, respectively. The quantitative results obtained by SWAdSV were consistent with those obtained by LC–MS/MS. The low-cost, easy-to-prepare, and disposable THY/PGE-based method provides a practical and straightforward alternative for the rapid and reliable determination of DA.