Browsing by Author "Montilla Martinez, Sebastian"
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Item Determinación simultánea de acetaminofén y levofloxacina usando un electrodo modificado con carbón vegetal y nanopartículas ecológicas de óxido de hierro y lantano(Universidad Santiago de Cali, 2025) Montilla Martinez, Sebastian; Morales Morales, Jimmy Alexander (Director)In this study, an electrochemical sensor was designed and evaluated, modified with environmentally low-impact materials and aimed at the simultaneous detection of two highly relevant pharmaceutical contaminants: acetaminophen (AC) and levofloxacin (LE). For this purpose, a glassy carbon electrode (GCE) was doped with a combined suspension of lanthanum ferrite (LaFeO₃) nanoparticles and activated vegetal carbon, both synthesized through a green synthesis process using molasses as an organic fuel, promoting an eco-friendly and cost-effective production pathway. The modification was performed using the drop-casting technique, applying 8 µL of the activated suspension (1:1 ratio), previously dispersed via ultrasonication. The electroanalytical performance of the system was characterized using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The modified electrode exhibited a well-defined voltammetric response, with two distinct, non-overlapping anodic peaks, confirming the feasibility of simultaneous and selective detection of both analytes under optimal conditions at pH 5. A linear response was achieved in the 20–60 µM range (R² = 0.966), with limits of detection and quantification of 9.20 µM and 27.88 µM, respectively. The analysis of peak current (Ip) versus the square root of the scan rate (√v) revealed a diffusion-controlled mass transport mechanism. Furthermore, the system showed a significant reduction in charge transfer resistance (Rct ≈ 27.7 kΩ) and an improvement in interfacial capacitance, attributed to the electrocatalytic synergy between the metal oxide and the carbonaceous support. The sensor demonstrated good repeatability (RSD < 10%) and operational stability up to 12 hours, with a signal loss of less than 14%, establishing it as a technically robust, reproducible, and environmentally sustainable alternative. These findings highlight the feasibility of employing eco-friendly materials and accessible fabrication techniques for the development of electrochemical sensing platforms, with promising applications in environmental monitoring, pharmaceutical analysis, and contaminated effluent assessment.