A Colorimetric Sensing of Hg(II) Ions Using 3-Mercaptopropionic Acid Modified Au Nanoparticles for the Undergraduate Chemistry Laboratory Curriculum

We demonstrate a simple method for the synthesis of gold nanoparticles via a boiling and refluxing methodology, as well as for the modification of 3-mercaptopropionic acid on the gold nanoparticles surface via Au—S self-assembled bonding. The experiment possesses several attractive features: the synthesis method circumvents the use of a surfactant or template; the selectivity and sensitivity experiments use small amounts of reagents (less than 1.0 mL); and the whole experiment can be carried out within 3 hrs at room temperature. In addition, this current experiment also provides students with an introduction to major concepts of nanoscale science and engineering including (i) size and scale, (ii) structure of matter, (iii) forces and interactions, (iv) self-assembly, (v) tools and instrumentation, and (vi) science, technology, and society. Hence, this experiment is suitable for incorporation into the undergraduate general chemistry laboratory curriculum. Students performed this experiment and improved their recognition of the nanoscale science and engineering concepts.