Highly Sensitive and Selective Colorimetric Sensing of Hg²⁺ Based on the Morphology Transition of Silver Nanoprisms

Abstract

A simple colorimetric approach for mercury ion (Hg 2+ ) sensing was developed that was based on the Hg 2+ -induced deprotection and morphology transition of 1-dodecanethiol (C 12 H 25 SH)-capped silver nanoprisms (Ag NPRs) upon the presence of iodides at room temperature. The abstraction of C 12 H 25 SH from the surface of Ag NPRs by Hg 2+ led to their deprotection of Ag NPRs and the formation of complexation between silver ions and excess iodide ions. Also, the silver atoms were consumed and moved from the surface of Ag NPRs, accompanying the changes in the particle morphology that resulted in a change of color and UV−vis absorption spectra of the colloidal solution. With increasing concentrations of Hg 2+ from 10 to 500 nM, the surface plasma resonance spectral band of Ag NPRs emerged as a blue shift and exhibited a good linear relationship, and the limit of detection was 3.3 nM. Furthermore, the developed method was applied for detecting Hg 2+ in different real water samples with satisfying recoveries over 92%.

Green Synthesis of Silver Nanoparticles Using Panax Ginseng Root Extract for the Detection of Hg2+

“…The reduced Hg 0 gets deposited onto the Ag surface forming an alloy of Hg-Ag, which is reported as lumps in earlier reports with the help of scanning electron microscopy observation. (43,45) The oxidation of AgNPs by Hg 2+ therefore decreases the concentration of AgNPs, and decolors the solution resulting in decreased absorption peak intensity.…”

“…In this redox reaction, such unexpected rapid redox reaction between the zero-valent Ag 0 and the divalent Hg 2+ occurs owing to the nanoscale nature of AgNPs, which heightens the effective variation between the Ag + /Ag nano and Hg 2+ /Hg redox potentials and would favor the reduction of Hg 2+ to Hg 0 with the partial oxidation of Ag 0 . (18,21,39,(43)(44)(45) Owing to the high affinity between Ag 0 and Hg 0 , the reduced Hg 0 gets deposited onto the Ag surface, resulting in the formation of the Hg-Ag alloy. (18,21,43,44) This further results in a decreased intensity and blue shift.…”

“…(18,21,39,(43)(44)(45) Owing to the high affinity between Ag 0 and Hg 0 , the reduced Hg 0 gets deposited onto the Ag surface, resulting in the formation of the Hg-Ag alloy. (18,21,43,44) This further results in a decreased intensity and blue shift. (18,21,43,44) To evaluate the degree of degradation of AgNPs due to Hg 2+ , a sensitivity factor (SF) has been decided and calculated and SF is calculated as…”

“…(18,21,43,44) This further results in a decreased intensity and blue shift. (18,21,43,44) To evaluate the degree of degradation of AgNPs due to Hg 2+ , a sensitivity factor (SF) has been decided and calculated and SF is calculated as…”

Colorimetric determination of copper ions based on the catalytic leaching of silver from the shell of silver-coated gold nanorods

“…Colorimetric methods based on nanomaterials are extremely attractive; in particular, for the sensing of ions and small organic molecules [11][12][13][14][15][16]. In comparison with other methods, they remained many advantages such as simplicity, reading out with the naked eyes, requiring no sophisticated starting materials and complex instruments.…”