Determination of acetaminophen and theophylline in drug samples by electrochemical method using Fe/MCM-41 modified electrode

In this study, we developed an electrochemical sensor based on an Fe/MCM-41 modified electrode for the simultaneous analysis of acetaminophen (AT) and theophylline (TP). The Fe/MCM-41 material was produced from diatomite silica and ferric chloride salts via a hydrothermal method. The synthesized material was characterized by XRD, SEM, TEM, EDX mapping, and nitrogen adsorption-desorption isotherms. Results showed that the Fe/MCM-41 maintained its mesoporous structure, high surface area, and uniform dispersion of Fe ions. Electrochemical tests revealed that the Fe/MCM-41 electrode exhibits superior electrocatalytic activity and higher current responses for both analytes than the bare electrode. The two oxidation peaks of AT and TP were distinctly separated, enabling simultaneous quantification of drugs with high selectivity. The peak current increased linearly with AT and TP concentrations from 0.50 to 14.15 µM, with detection limits of 0.430 and 0.350 µM, respectively. Notably, the sensor was successfully used to analyze pharmaceutical formulations containing one or both active substances, with satisfactory recoveries. The results confirm that the Fe/MCM-41 electrode is a promising sensing platform for the simultaneous analysis of AT and TP, opening new possibilities for pharmaceutical testing.