Sugarcane bagasse-derived silica/carbon composite electrode for tetracycline detection

Tetracycline (Tc), a widely employed antibiotic in medical treatments and animal husbandry, is frequently released into environmental matrices, posing significant concerns related to food safety, human health, and ecological stability. Consequently, detecting Tc at trace concentrations through methods that are cost-effective, rapid, and highly selective remains a critical and ongoing research challenge. Carbon paste sensors (CPS) are widely recognized as versatile tools for electrochemical sensing applications. A particularly promising approach for enhancing sensor performance involves incorporating cost-effective and eco-friendly agro-industrial residues, such as biosilica derived from sugarcane ash. This study proposes the modification of CPS with commercial silica gel (Si-CPS) and biosilica (BioSi-CPS) for the electrochemical detection of Tc. Experimental findings demonstrate that Tc efficiently accumulates on the surface of the modified sensors, significantly enhancing their oxidation current response. Differential pulse voltammetry (DPV) was employed to evaluate Tc detection, with BioSi-CPS exhibiting superior electrochemical performance. This enhancement is attributed to the increased electroactive surface area and improved electrochemical properties introduced by the biosilica modification. Using BioSi-CPS, Tc was reliably detected at low concentrations, exhibiting linear response ranges of 6–80 μmol L⁻¹ and 100–1000 μmol L⁻¹. The sensor demonstrated excellent stability and reproducibility, with no significant interference from common excipients such as glucose, ascorbic acid, citric acid, and mannose. The results highlight the potential of biosilica-modified CPS as an effective, sustainable, and cost-efficient, and highly selective platform for the detection of tetracycline in environmental monitoring applications.