Efficient electrochemical sensor for trace detection of sulfamethazine in spring water: Use of novel nanocomposite material coated with Ag or Au nanoparticles

Sulfamethazine (SMZ), a persistent antibiotic, is often detected in water bodies including drinking water sources at low levels. Hence, it is a global interest to develop sensitive and selective sensors for its trace and on-site detection. The present study entails the novel synthesis of nanocomposites precursor to the bentonite and silane. The nanocomposites were coated with Ag and Au nanoparticles which were prepared by a greener route utilizing natural phytochemicals. The nanocomposite materials are systematically characterized by Fourier transform infra-red, scanning electron microscopy/energy dispersive X-ray analysis, transmission electron microscope (TEM) and atomic force microscope analyses. The TEM analysis showed that small-sized Ag and Au nanoparticles were spherical in shape and evenly distributed over the nanocomposite materials. Further, the nanocomposite materials were intended to be utilized indigenously in the fabrication of micro-electrodes for the detection of trace SMZ using the differential pulse anodic stripping voltammetry. The cyclic voltammetric studies indicated that SMZ would be oxidized at ca. 0.12 V (vs Ag/AgCl) and the process is found irreversible in nature since no reduction peak appeared in the reverse scan. The optimized conditions for determination of SMZ were found to be pH 4.0, deposition potential of −1.2 V (vs Ag/AgCl), and deposition time of 180 s. Further, the limit of detection of the method based on the nanocomposite solid was determined to be 0.097 µM. Lastly, the method was employed for quantifying SMZ in spring water; a reasonably high recovery could be achieved.