SYNTHESIS OF GOLD NANOPARTICLES AND COLORIMETRIC SENSING OF THE SULFATHIAZOLE: AN EXPERIMENTAL PRACTICE FOR INTERDISCIPLINARY CLASSES

Students undertaking courses in the field of sciences and engineering need to learn practical skills and conceptual knowledge, and the experimental classes are the best moment for this. In this paper, we propose a practical experiment to aid nanotechnology learning by synthesizing gold nanoparticles (AuNPs) and their application as a colorimetric sensor of sulfathiazole. AuNPs were prepared using sodium citrate as a reducing and capping agent. The existence of the synthesized AuNPs was detected using the Tyndall effect while their optical properties were investigated by molecular absorption spectrophotometry. The gold nanoparticles exhibit spherical-like shape morphology and an average size of 13.6 nm, determined by transmission electron microscopy. The AuNPs were applied as a colorimetric sensor for the detection of sulfathiazole in mixed water/ethanol solution by simple visual inspection and using molecular absorption spectrophotometry. Due to the simplicity of the experimental steps, this activity is well-suited for a hands-on introduction of nanoparticles synthesis and its application as a molecular sensor. In addition, the experiment encompasses knowledge from different fields being suitable for interdisciplinary classes.