Colorimetric Sensing Techniques for Mercury Ion Detection

The detection of mercury ions in environmental and biological matrices is critical due to their high toxicity and persistence. Colourimetric sensing techniques harness visual changes in reagent colour upon interaction with Hg(II), enabling rapid, cost-effective detection without complex instrumentation. Common approaches employ metal nanoparticles—typically silver or gold—stabilised by organic capping agents that undergo aggregation or surface etching in the presence of mercury. This interaction alters localized surface plasmon resonance bands, producing visible shifts in solution colour. Advances in green synthesis have introduced biocompatible and sustainable nanomaterials, while portable platforms such as paper-based tests and smartphone integration have enhanced field applicability. Recent developments have also leveraged nanozyme activities to generate chromogenic responses. These methodologies combine selectivity for Hg(II) with sub-ppb sensitivity, offering practical solutions for monitoring drinking water, industrial effluents and ecological habitats.

Research from Nature Portfolio

Recent studies have demonstrated the potential of phytomediated silver nanoparticles to form amalgams with Hg(II), driving a distinct colour transition from brown to colourless via amalgam-induced etching of nanoparticle surfaces. This simple assay achieves detection limits in the low parts-per-billion range, with high accuracy and precision in aqueous samples. Complementary work on polyvinylpyrrolidone-stabilised silver nanoparticles has revealed peroxidase-like catalytic activity that, when inhibited by mercury ions, produces a quantifiable chromogenic change. This nanozyme-based approach delivers both colourimetric and fluorescence readouts, with limits of detection down to single-digit nanomolar concentrations, and has been validated for water sample analysis.

Colorimetric Sensing Techniques for Mercury Ion Detection publication trend

The graph below shows the total number of articles in colorimetric sensing techniques for mercury ion detection across all publications each year (not limited to Nature Index journals).

Technical terms

Colourimetric sensing: Analytical method where the concentration of an analyte is inferred from a change in colour intensity or hue.

Localized surface plasmon resonance (LSPR): Collective oscillation of conduction electrons in metal nanoparticles that produces a sharp absorption band sensitive to particle size, shape and surrounding environment.

Aggregation-induced colour change: Transition in solution colour resulting from nanoparticle clustering that alters plasmonic properties.

Amalgam formation: Chemical process where mercury atoms intercalate into or alloy with a metal substrate, modifying optical characteristics.

Limit of detection (LOD): The lowest concentration of an analyte that can be reliably distinguished from background signal.

References

1. Selective interaction between phytomediated anionic silver nanoparticles and mercury leading to amalgam formation enables highly sensitive, colorimetric and memristor-based detection of mercury. Scientific Reports (2020).
2. Utilization of the peroxidase-like activity of silver nanoparticles nanozyme on O-phenylenediamine/H2O2 system for fluorescence detection of mercury (II) ions. Scientific Reports (2022).
3. Visual and colorimetric determination of mercury (II) based on lignosulfonate-capped silver nanoparticles. Green Chemistry Letters and Reviews (2023).
4. Smartphone Coupled with a Paper-Based Colorimetric Device for Sensitive and Portable Mercury Ion Sensing. Chemosensors (2019).
5. Colorimetric Detection of Mercury Ions in Water with Capped Silver Nanoprisms. Materials (2019).