A method for mercury (ΙΙ) ions detection was developed by using 2-mercaptobenzothiazole (MBT) with gold nanoparticles (MBT-AuNPs). The MBT-AuNPs can be induced to aggregate in the presence of Hg(ΙΙ) ions resulting in the change in solution color from pink to purple. The solution was then analyzed by UV-VIS spectrophotometer at 680 and 530 nm. Parameters that affected the Hg(II) determination including gold nanoparticles concentration, MBT concentration, particles sizes of gold nanoparticles, reaction time were optimized. The detection of Hg(II) could be performed by using 0.25 mM AuNPs solution modified with 5.0 µM MBT solution with the total analysis time of 3 min. The suitable pH for Hg(II) determination was pH 4-5. A good linearity (R² = 0.99) was obtained for the determination of Hg(II) in the concentration range of 20-100 μg/L with the detection limit of 5 μg/L. The detection can be performed spectrophotometrically and visually.

Thesis (M.Sc.)--Chulalongkorn University, 2012