Colorimetric and Fluorescent Detection of Nickel Ions in Aqueous Systems

Nickel contamination in water sources poses significant environmental and health risks, driving the development of rapid, sensitive and affordable analytical methods. Colourimetric assays exploit visible changes in solution hue upon interaction with nickel ions, enabling naked‐eye detection or simple spectrophotometric quantification. Fluorescent approaches rely on molecular probes whose emission properties vary selectively in the presence of Ni2+, affording high sensitivity and the potential for real‐time monitoring in complex matrices. Recent advances have focused on organic chromophores and nanomaterials engineered for submicromolar detection limits, with emphasis on selectivity against competing metal ions, signal reversibility, pH tolerance and adaptability to field‐deployable formats. Integration into paper strips, dipsticks and microfluidic devices further enhances practical application. Computational studies and mechanistic investigations have elucidated ligand–metal interactions, guiding the rational design of next‐generation sensors that balance performance, cost and ease of use for environmental monitoring and biomedical diagnostics.

Research from Nature Portfolio

Highly selective 2,7‐naphthyridine‐based chemosensors have been developed as dual colourimetric and “turn‐off” fluorescent probes for Ni2+ in aqueous media. A family of receptors displays a reversible yellow‐to‐red colour change and substantial fluorescence quenching upon nickel binding, with detection limits down to 0.04–0.5 µM—below drinking‐water guidelines. Binding stoichiometries of 2 : 1 are confirmed by mass spectrometry and Job’s plot, while density functional theory supports ligand–metal charge‐transfer mechanisms. Crucially, these sensors maintain performance across a broad pH range and can be incorporated into dip‐stick test strips for in-field measurements, demonstrating combined sensitivity, selectivity and user-friendly operation for environmental assessment.

Colorimetric and Fluorescent Detection of Nickel Ions in Aqueous Systems publication trend

The graph below shows the total number of articles in colorimetric and fluorescent detection of nickel ions in aqueous systems across all publications each year (not limited to Nature Index journals).

Technical terms

Colorimetric detection: A method based on visible colour changes in solution upon interaction with target ions.

Fluorescent probe: A molecule that emits light on excitation, with emission intensity or wavelength altered by analyte binding.

Turn-off sensor: A fluorescent sensor whose emission decreases upon binding to the target ion.

Turn-on sensor: A fluorescent sensor whose emission increases upon interaction with the target ion.

Limit of detection: The lowest analyte concentration that yields a signal distinguishable from background noise.

Binding stoichiometry: The ratio of sensor molecules to metal ions in the formed complex.

References

1. A novel “off-on” fluorescent probe for the detection of nickel ions and its clinical application. Frontiers in Bioengineering and Biotechnology (2023).
2. Simple and rapid colorimetric sensing of Ni(II) ions in tap water based on aggregation of citrate-stabilized silver nanoparticles. Sustainable Environment Research (2019).
3. Naphthyridine derived colorimetric and fluorescent turn off sensors for Ni2+ in aqueous media. Scientific Reports (2021).
4. Chalcone-Based Colorimetric Chemosensor for Detecting Ni2+. Chemosensors (2022).