Ultrasensitive detection of Ag⁺and Ce³⁺ions using highly fluorescent carboxyl-functionalized carbon nitride nanoparticles

Narendra Chaulagain ¹, John C Garcia ¹, Aparna Manoj ²

⁰Department of Electrical and Computer Engineering, University of Alberta, 9211-116 St, Edmonton, AB T6G 1H9, Canada.

Nanotechnology +

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April 11, 2024

View abstract on PubMed

Summary

Carboxyl-rich graphitic carbon nitride (g-C3N4) nanoparticles exhibit selective fluorescence quenching for detecting Ag+ and Ce3+ ions. This offers a sensitive method for heavy metal ion detection with potential for on-site applications.

Area Of Science

Materials Science
Nanotechnology
Analytical Chemistry

Background

Graphitic carbon nitride (g-C3N4) nanoparticles are synthesized via solid-state thermal polycondensation.
These nanoparticles exhibit distinct green fluorescence, high water solubility, and an average size of 95 nm.
They possess absorption and emission maxima at 405 nm and 540 nm, respectively, leading to a large Stokes shift.

Purpose Of The Study

To develop a selective and sensitive fluorescence quenching-based sensor for heavy metal ions.
To investigate the interaction mechanism between g-C3N4 nanoparticles and specific metal ions.
To demonstrate the practical applicability of the sensor for on-site detection.

Main Methods

Synthesis of carboxyl-rich g-C3N4 nanoparticles using solid-state thermal polycondensation.
Characterization of nanoparticle size using dynamic light scattering.
Photoluminescence spectroscopy to determine absorption/emission maxima and study fluorescence quenching.
Analysis of metal ion sensing mechanism using modified Stern-Volmer kinetics.

Main Results

The g-C3N4 nanoparticles demonstrated selective fluorescence quenching for Ag+ and Ce3+ ions.
A low limit of detection of 30 pM was achieved for Ag+ ions.
The sensing mechanism followed modified Stern-Volmer kinetics with a high K_app value (8.9 × 10^4 M^-1) for mixed Ag+/Ce3+ ions.
Successful demonstration of on-site sensing using functionalized filter paper.

Conclusions

Carboxyl-rich g-C3N4 nanoparticles serve as effective fluorescent probes for selective detection of Ag+ and Ce3+.
The developed sensor offers high sensitivity and potential for practical, on-site heavy metal ion monitoring.
The strong interaction and efficient quenching mechanism highlight the utility of these nanoparticles in analytical applications.

Keywords:

2D materials environmental monitoring fluorescence quenching heavy metal ion sensing quenching kinetics