Molasses-Assisted Green Combustion Synthesis of LaFeO3 Perovskites: Structural and Interfacial Insights for the Simultaneous Electrochemical Determination of Acetaminophen and 4-Aminoantipyrine

Sugarcane molasses-assisted combustion was employed to synthesize two LaFeO3 perovskite formulations (ELF-4 and ELF-6). X-ray diffraction and Rietveld refinement supported the formation of the orthorhombic Pnma structure, while vibrational spectroscopy and electron microscopy revealed formulation-associated differences in surface-related features and aggregate morphology. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrated distinct interfacial responses without establishing a generalized enhancement in electron-transfer kinetics following LaFeO3 modification. At pH 3.5, ELF-4-modified screen-printed carbon electrodes (ELF-4/SPCE) exhibited distinguishable oxidation signals for acetaminophen (AC) and 4-aminoantipyrine (4-AAP). Differential pulse voltammetry of equimolar mixtures provided concentration-dependent responses over 20–180 µM, with sensitivities of 0.0969 µA µM−1 for AC (R2 = 0.997) and 0.0192 µA µM−1 for 4-AAP (R2 = 0.927). Cross-concentration experiments revealed asymmetric analyte interactions, indicating that peak discrimination does not necessarily ensure independent quantitative responses. Exploratory measurements in diluted and fortified campus garden fountain and tap water samples yielded distinguishable signals, although joint standard additions did not establish reliable individual quantification. These findings demonstrate the feasibility of molasses-derived LaFeO3 as an electrochemical sensing modifier while identifying limitations that must be addressed for accurate simultaneous analysis.