A Novel Poly(Bromophenol Blue)-Coated Glassy Carbon Electrode for Sensitive Electrochemical Sensing of Melatonin
CHEMISTRYSELECT, vol.11, no.21, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 11 Issue: 21
- Publication Date: 2026
- Doi Number: 10.1002/slct.202507159
- Journal Name: CHEMISTRYSELECT
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Academic Search Ultimate (EBSCO)
- Karadeniz Technical University Affiliated: Yes
Abstract
In this study, a bromophenol blue polymer film coated glassy carbon electrode was prepared and used for the sensitive voltammetric analysis of melatonin. After optimizing the conditions, bromophenol blue was electrochemically polymerized onto the glassy carbon electrode surface by cyclic voltammetry in a phosphate buffer at pH 5.9 containing 0.05 M NaNO3. Following characterization of the modified electrode using cyclic voltammetry and electrochemical impedance spectroscopy, voltammetric analysis of melatonin with the modified electrode was carried out in pH 8.0 Britton-Robinson buffer. A linear dependence between melatonin concentration and anodic peak current was obtained in the range of 0.06-10 & micro;M for differential pulse voltammetry and 0.1-40 & micro;M for square wave voltammetry, with detection limits of 17.0 and 29.9 nM, respectively. Interference studies revealed that common potential interfering substances had minimal effect on the electrochemical responses, supporting the selectivity of the sensor. The applicability of the voltammetric methods in the melatonin determination was evaluated in pharmaceutical oral dosage form, spiked human serum, and artificial urine samples, achieving recoveries between 99.84% and 100.83%. Additionally, the modified electrode demonstrated reliable reproducibility with an RSD of 0.54% (n = 5) and notable stability for up to 9 days when stored under laboratory conditions.