Preventing On-Farm Antibiotic Toxicity: A Green Polyaniline Potentiometric Sensor for On-Farm Monitoring of Valnemulin

Abstract

Valnemulin hydrochloride (VML), a critical antibiotic used in swine medicine, poses significant toxicity risks—including hepatotoxicity and microbial resistance—when misdosed in livestock. To address this, a green, disposable polyaniline-based solid-contact ion-selective electrode (SC-ISE) was developed for rapid VML quantification in veterinary pharmaceuticals and farm samples. The sensor integrates calix[8]arene as a high-affinity ionophore, enabling detection at therapeutically relevant levels (1.0 × 10 −6 to 1.0 × 10 −2 mol l −1 ) with a Nernstian slope (57.27 ± 0.4 mV decade −1 ) and ultra-low detection limit (3.31 × 10 –7 mol l −1 ). The proposed sensor demonstrated a rapid response time of 20 ± 3 s and a long operational lifetime of up to one month. Crucially, the electrode selectively distinguishes VML from its degradation products and common interferents (e.g., feed additives, ions). Validation in swine serum and feed samples confirmed accuracy (98%–102% recovery), outperforming HPLC. Green metrics (Eco-Scale: 85, AGREE: 0.82) underscore its sustainability vs lab-based methods. By enabling on-farm toxicity prevention, this sensor offers a proactive solution to safeguard animal welfare and combat antibiotic resistance.