فهرست نشریات علمی دسترسی آزاد ایران

This research investigated the electrochemical impedance spectroscopy (EIS) behavior of copper electrodes modified with electroencephalography gel (EEG gel) together with non-functionalized multi-walled carbon nanotubes (NF-MWCNT@IN), and carboxylic acid functionalized multi-walled carbon nanotubes (MWCNT-COOH@IN) both serving as phthalate impedimetric nanosensors. The Fe2+/Fe3+ redox couple was chosen as the electrochemical signal generator. Phthalic acid esters (PAEs) were applied to block the nanosensor surface and diminish the electrochemical signal of the Fe2+/Fe3+ couple. The outcomes revealed a significant blocking effect of PAEs at the molecular scale, substantiating their effectiveness in signal suppression. Additionally, a good linearity between the concentrations of PAEs blockers and signal diminishing was observed, confirming the quantitative capability of the nanosensor system for PAEs detection. The results for NF-MWCNT@IN demonstrated that larger phthalates induced a greater increase in charge transfer resistance, indicating more substantial blocking at the electrode interface. Conversely, in the case of MWCNT-COOH@IN, the charge transfer resistance increased with smaller phthalates. These constructed impedimetric nanosensors (IN) were successfully applied to quantify PAEs concentrations in real water samples. The relative recovery percentages ranged from 96% to 99% with relative standard deviations (RSDs %) between 0.34% and 1.87% for NF-MWCNT@IN, while MWCNT-COOH@IN exhibited recoveries between 92% and 99% with RSDs ranging from 0.44% to 3.05%. These results confirm the high sensitivity, accuracy, and reproducibility of the nanosensors for detecting PAEs in environmental samples by EIS, highlighting charge transfer resistance as a key metric for sensor performance and molecular interaction effects at the electrode surface.