Ionic liquid/multiwalled carbon nanotube composite as an electrochemical sensor for the determination of Schisandrol A

This work aimed to determine Schisandrol A in pharmaceutical and biological media using an ionic liquid/multiwalled carbon nanotube (IL/MWCNT) composite modified glassy carbon electrode as a sensitive electrochemical sensing platform. Microscopic and spectroscopic characterization confirmed uniform incorporation of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) within the functionalized multiwalled carbon nanotube (MWCNT) network. Relative to the bare electrode, the composite markedly enhanced interfacial charge transfer and electroactive area (peak-to-peak separation, ΔEp: 158 to 68 mV; charge-transfer resistance, Rct: 850 to 45 Ω; electroactive area: 0.071 to 0.340 cm²), enabling sensitive adsorptive stripping differential pulse voltammetry. The oxidation current exhibited linearity from 0.01 to 50 µM with a detection limit of 3.5 nM. The sensor showed good precision and stability and enabled accurate quantification in Schisandra capsules and spiked human serum with results consistent with high-performance liquid chromatography with ultraviolet detection (HPLC-UV). This work demonstrates that ionic liquid assisted dispersion and binding of MWCNTs provides a simple and low cost platform for rapid quality control and bioanalytical screening of Schisandrol A.