A naked-eye colorimetric assay for detection of Hg2+ ions in real water samples based on gold nanoparticles-catalyzed clock reaction

Hamzeh Khani, Shahryar Abbasi*, Mohammad Tavakkoli Yaraki*, Yen Nee Tan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Designing a simple, inexpensive, and sensitive colorimetric sensor for the detection of toxic species in drinking water is of great importance. In this paper, we have demonstrated a simple and sensitive colorimetric assay for naked-eye detection of mercury ions (Hg2+) in water based on gold nanoparticles-catalyzed clock reaction. Citrate-capped Au nanoparticles (AuNPs) were used to catalyze the reduction of methylene blue (MB) to leucomethylene blue (LMB) by hydrazine. However, Hg2+ ions can reduce the catalytic activity of AuNPs in this clock reaction, resulting in the longer reaction time for color transformation of MB from blue to colorless LMB solution. Based on this principle, we have developed an ultrasensitive colorimetric assay that can selectively detect Hg2+ in the concentration range of 5 to 1000 nM with a limit of detection (LOD) of 4.3 nM, which is well below the maximum allowable concentration for Hg2+ in drinking water (10 nM) as defined by the United States Environmental Protection Agency. Owing to the rapidity and simplicity of the naked eye detection process, we expect that this AuNPs-catalyzed clock reaction could put forward an insight for the detection of toxic Hg2+ ions in real water samples, opening up new avenues for developing cost-effective and portable nanosensors for environmental applications.
Original languageEnglish
Article number118243
Pages (from-to)1-8
Number of pages8
JournalJournal of Molecular Liquids
Volume345
DOIs
Publication statusPublished - 1 Jan 2022
Externally publishedYes

Keywords

  • Colorimetric determination
  • Clock reaction
  • Methylene blue reduction
  • Au nanoparticle
  • Hg2+ determination
  • Hg determination

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