Green and efficient: deep eutectic solvents as key enablers in electrochemical sensors for oxytetracycline

The widespread use of oxytetracycline (OTC) in medicine, livestock, and aquaculture has led to persistent environmental residues, underscoring the need for rapid, sensitive, and sustainable monitoring tools. This review critically evaluates the role of deep eutectic solvents (DES) as green and efficient components in the development and optimization of electrochemical sensors for the detection of OTC. Evidence from recent studies indicates that DES-based sensors exhibit strong analytical performance, including nanomolar detection limits (LOD ≈ 10⁻⁹ M), a wide linear range spanning three orders of magnitude, and excellent reproducibility (RSD < 5%). These improvements are examined in relation to key factors that underpin sensor enhancement, namely rational design and classification of DES, advanced material characterization techniques, and innovative electrochemical measurement strategies. Furthermore, the review critically addresses current challenges, such as batch-to-batch variability and matrix effects in complex samples. It highlights future directions focused on real-sample validation and integration of DES-based platforms with portable potentiostats for on-site analysis.