Analytical Sciences

Colorimetric Detection of Mercury(II) Ion in Aqueous Solution Using Silver Nanoparticles

M. Lutfi FIRDAUS,*1 Ikka FITRIANI,*1 Santhy WYANTUTI,*2 Yeni W. HARTATI,*2 Renat KHAYDAROV,*3 Jason A. MCALISTER,*4 Hajime OBATA,*5 and Toshitaka GAMO*5

*1 Graduate School of Science Education, University of Bengkulu, Bengkulu 38371, Indonesia
*2 Department of Chemistry, University of Padjadjaran, Bandung 40132, Indonesia
*3 Institute of Nuclear Physics, Uzbek Academy of Sciences, Tashkent 100214, Uzbekistan
*4 Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, BC V6T 1Z4, Canada
*5 Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan

Novel green-chemistry synthesis of silver nanoparticles (AgNPs) is introduced as a low-cost, rapid and easy-to-use analytical method for mercury ion detection. Aqueous fruit extract of water apple (Syzygium aqueum) was used for the first time as bioreductant to synthesize stable AgNPs. The prepared AgNPs have a yellowish-brown color with a surface plasmon resonance peak at 420 nm. The addition of Hg(II) ions then changes the AgNPs color to colorless. The color change was in proportion to the concentration of Hg(II) ions. The presence of other metal ions in the system was also evaluated. The proposed method shows good selectivity and sensitivity towards Hg(II) ions. Using UV-visible spectrophotometry, the detection limit of the developed method was 8.5 × 10⁻⁷ M. The proposed method has been successfully applied for determination of Hg(II) ions in tap and lake water samples with precision better than 5%.

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