One-step synthesis of ultrafine silver-decorated polyaniline nanowire arrays for trace analysis of sulfamethoxazole

Sulfamethoxazole (SMX), a broad-spectrum antibiotic, has potential risk of ecological damage and human health, due to its over-dosage utilization and wanton discharge. It is desirable to develop a highly sensitive sensor for the rapid and accurate determination of SMX to evaluate the environmental risk of antibiotics. Herein, an ultrafine Ag nanoparticles-decorated polyaniline nanowire arrays (AgNPs-PANI-NAs) were successfully formed on the carbon nanofibers (AgNPs-PANI-NAs@CNF) by in-situ one-step redox reaction. The PANI wire length around CNFs and the AgNPs amount were conveniently tuned by adjusting Ag + concentration. The conductivity and electrochemical activity of the AgNPs-PANI-NAs@CNF were significantly improved. With AgNPs-PANI-NAs@CNF as sensing material, the resultant AgNPs-PANI-NAs@CNF modified glassy carbon electrode (AgNPs-PANI-NAs@CNF/GCE) presented a super-high electrochemical response to the oxidation of SMX by strong interaction of SMX with the sensing interface. A wide linear range (1 nM ∼ 10 μM) was achieved with an ultra-low detection limit (80 pM, S/N>3). The chronocoulometry measurement proved that the adsorption capacity of SMX at AgNPs-PANI-NAs@CNF/GCE was significantly enhanced, thus improving the sensitivity of SMX detection. The related reaction mechanism and strong interaction of SMX with AgNPs-PANI-NAs were demonstrated by X-ray photo spectroscopy and ultraviolet-visible spectroscopy characterization. This work provides a novel strategy of constructing high-performance sensing materials for pollutants analysis in environmental waters.