Akademik Veri Yönetim Sistemi
Synthetic Metals, cilt.319, 2026 (SCI-Expanded, Scopus)
In this study, a novel and efficient electrochemical sensing platform for the determination of niflumic acid (NFA) was developed based on a quaternary ammonium salt–assisted modification of a pencil graphite electrode (PGE) in a non-aqueous medium. The electrode surface was electrochemically polarized using tetrabutylammonium hexafluorophosphate (TBAPF₆) dissolved in dimethyl sulfoxide (DMSO), leading to the formation of a positively charged and ionically organized interface. Systematic optimization studies revealed that the optimal electrode fabrication conditions were obtained using 0.025 M TBAPF₆ in DMSO, two cyclic voltammetric cycles, and a synthesis potential window of −0.2 to −2.75 V. Electrochemical impedance spectroscopy (EIS) demonstrated a pronounced decrease in charge-transfer resistance from 128.54 Ω for the bare PGE to 82.08 Ω for the TBAPF₆/DMSO/PGE, confirming significantly enhanced interfacial electron-transfer kinetics. The modified electrode exhibited excellent electroanalytical performance toward niflumic acid in Britton–Robinson buffer (pH 5.0), providing a low detection limit of 1.61 × 10⁻⁷ M (161 nM), a quantification limit of 5.38 × 10⁻⁷ M, and good repeatability with an RSD of 3.49%. The sensor showed high selectivity in the presence of common interfering species and was successfully applied to real pharmaceutical samples, yielding recoveries between 100.59% and 104.75%. Furthermore, ferri/ferrocyanide probe studies confirmed that the enhanced electrochemical response originates from intrinsic improvements in interfacial conductivity rather than analyte-specific effects. Complementary spectroscopic and morphological characterizations (SEM, FT-IR, and XRD) further support the successful surface modification of the electrode. The proposed TBAPF₆/DMSO/PGE platform offers a simple, cost-effective, and reliable alternative for sensitive niflumic acid determination in pharmaceutical analysis.