Development of a New Generation MWCNT/TiO2/TiO2-Based Voltammetric Sensors for the Detection of Daptomycin in Soil and Different Water Samples

Daptomycin is a pioneer cyclic lipopeptide antibiotic introduced for clinical use. It is effective against gram-positive bacteria, but its widespread use raises the problem of pollution in environmental samples. For this purpose, rapid, sensitive, selective, and applicable analytical methods for daptomycin in these environmental matrices are needed. In this work, electrochemical method was advanced with a glassy carbon electrode (GCE) and newly developed multi-walled carbon nanotubes/titanium dioxide nanoparticles/titanium dioxide nanoparticles modified GCE (MWCNT/TiO₂/TiO₂/GCE) for the daptomycin detection using adsorptive stripping differential pulse voltammetry. The surface characterization of the supported sensor was researched. Under optimized conditions, the linear range for the unmodified electrode and MWCNT/TiO₂/TiO₂/GCE was 0.2–1.0 μM and 0.06–5.0 μM, with detection limits of 0.086 μM and 0.001 μM. The selectivity of the proposed sensor was investigated for organic and inorganic compounds that could affect the detection of daptomycin by interference studies. The accuracy of the methods proposed for determining daptomycin in different environmental (soil, natural spring, and tap water) samples was calculated as % recovery in recovery studies. A novel, fast, reliable, cost-effective, eco-friendly, sensitive, and highly selective sensor was developed for the first time to determine daptomycin in environmental samples, introducing a new analytical method to the literature.