Hydrothermal synthesis of SnO2 nanoparticles for electrocatalytic detection of perfluorononanoic acid and perfluorooctanesulfonic acid in environmental samples using voltammetric techniques.

Perfluorochemicals are synthetic compounds used in many applications; however, their slow degradation classifies them as emerging micropollutants that persist in the environment. Long-term exposure to perfluorononanoic acid (PFNA) and perfluorooctanesulfonic acid (PFOS) via soil, water, and food can cause human health problems. In this research, SnO2 nanoparticles were synthesized hydrothermally to study the electrocatalytic detection of PFNA and PFOS. The tin oxide (SnO2) nanoparticles were characterized by scanning electron microscopy and X-ray diffraction, which showed a tetragonal rutile structure with an average crystallite size of 68.5 nm and particle sizes ranging from 53 to 225 nm. Electrochemical properties of SnO2-coated carbon paste electrodes (SnO2/CPE) were used in cyclic voltammetry and square wave voltammetry to investigate the sensing properties of the materials developed. Due to their higher electroactive surface area and faster charge transfer rates, SnO2/CPE exhibits higher sensitivity with detection limits of 15.9 nM (0.0159 μM; 7380 ppm) for PFNA and 30.7 nM (0.0307 μM; 15,350 ppt) for PFOS, respectively. The ECSA of SnO2/CPE was 0.068 cm2 vs 0.042 cm2 in the nascent CPE, representing a 1.6-fold increase in the active sites. The sensor demonstrated sensitivities of 58.11 μA μM-1·cm-2 (PFNA) and 25.03 μA μM-1·cm-2 (PFOS), respectively while the recoveries of PFAAs in spiked soil and water samples ranged between 87.0 and 95.46 %, and 87.5-94.7 %, respectively with RSD of 2.0-3.5 %. The study outlines the capabilities of SnO2 nanoparticles to produce low-cost, high-efficiency sensors to detect pollutants, suggesting the potential future environmental monitoring applications.