Rare earth orthovanadate (REM-VO4; REM = Pr, Gd, and Sm)-based sensors for selective and simultaneous detection of furazolidone and metronidazole†

Abstract

Antibiotics are vital tools in the fight against bacterial infections, with furazolidone (FD) and metronidazole (MD) being widely used to target pathogens like G. lamblia and H. pylori. However, overuse of these antibiotics can lead to serious health complications, highlighting the urgent need for accurate, real-time detection of these drugs at precise levels. In this study, we explore the use of differential pulse voltammetry (DPV) for detecting FD and MD with high sensitivity, employing a dual detection method. To enhance detection, we developed a sensor using rare earth metal-based orthovanadates (REM-VO₄, where REM = Pr, Gd, and Sm) as electrode modifiers. These materials offer exceptional surface control, boosting the sensor's sensitivity and selectivity. Among the different configurations, the SmVO₄-modified glassy carbon electrode (SmV/GCE) stands out, demonstrating the lowest charge transfer resistance (R_ct = 56.82 Ω) and the largest electrochemical surface area (A = 0.11 cm²). SmVO₄'s unique nanostructure, with its high electrochemically active surface area and hollow structure, is key to its impressive performance. This sensor not only provides the lowest limits of detection (0.0009 μM for FD and 0.0036 μM for MD individually, and 0.0015 μM and 0.0049 μM for simultaneous detection) but also shows excellent anti-interference, repeatability, and reproducibility. Furthermore, SmV/GCE has been successfully applied for real-time analysis of biological and environmental samples, offering recoveries between 97.33 to 99.60%, demonstrating its practical potential for precise antibiotic monitoring.