A novel low –cost and sensitive sensor for the voltammetric nano detection of linezolid antibiotic in real samples using carbon paste electrode modified with calcium oxide nanoparticle combined with electropolymerized D-alanine

This study reports the development of a novel, low-cost, and highly sensitive sensor for the rapid and efficient electrochemical detection of trace amounts of the antibiotic Linezolid (LNZO) in both synthetic solutions and real samples. The proposed sensor is based on a carbon paste electrode (CPE) modified with calcium oxide nanoparticles (CaO-NPs) and further enhanced through electropolymerization of D-alanine (PoDA). Eggshell waste was recycled as a low-cost and eco-friendly source of calcium oxide nanoparticles (CaO-NPs). The synergistic effect of CaO-NPs and the electropolymerized D-alanine (PoDA) film enhanced the electrocatalytic activity of the carbon paste electrode (CPE) toward Linezolid (LNZO). The fabricated sensor was characterized using FTIR, XRD, and SEM techniques. It exhibited excellent electro-oxidation performance toward LNZO, demonstrating high sensitivity, a very low detection limit, good selectivity, and acceptable reproducibility. Differential pulse voltammetry provided a wide linear range (0.005-0.1 µM) with a detection limit of 1.27 nM. Importantly, the sensor successfully detected LNZO in real samples, achieving recovery rates between 95.70% and 100.20%, confirming its effectiveness for practical applications the developed sensor confirmed the ability to identify LNZO in real samples, yielding acceptable recovery percentages within the range of 95.70% to 100.20%, proving the method's effectiveness in practical applications.