Portable Fluorescence Photonic Crystal (NCQD@ZIF-8) Sensor for Ferric and Ascorbic Acid Detection

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Accurate detection of ferric/ferrous ions is crucial for environmental monitoring and healthcare.
• Solid-state fluorescent sensors are preferred over liquid-based sensors due to stability against oxidation and precipitation.
• There is a need for novel solid-state fluorescent sensors for ion detection.

Purpose of the Study:

• To develop a portable, solid-state fluorescent sensor for the simultaneous detection of Fe³⁺ and ascorbic acid (AA).
• To utilize nitrogen-doped carbon quantum dots (NCQDs) encapsulated in ZIF-8 photonic crystals (PCs) for enhanced fluorescence.
• To enable rapid and selective iron speciation analysis in environmental samples.

Main Methods:

• Fabrication of NCQD@ZIF-8 photonic crystal (PC) sensor via rapid evaporation self-assembly.
• Utilizing the fluorescence quenching effect of Fe³⁺ on NCQDs.
• Employing the fluorescence recovery mechanism by AA reduction of Fe³⁺ to Fe²⁺ for iron speciation.

Main Results:

• The NCQD@ZIF-8 PC sensor exhibited enhanced fluorescence due to the slow light effect of ZIF-8.
• Selective detection of Fe³⁺ and AA achieved in the linear range of 0.1–10 mmol L⁻¹ with low detection limits.
• Successful iron speciation analysis (Fe³⁺/Fe²⁺) in simulated water samples with high precision and accuracy.

Conclusions:

• The developed NCQD@ZIF-8 PC sensor offers a rapid, portable, and selective method for Fe³⁺ and AA detection.
• The sensor facilitates accurate iron speciation analysis in environmental water samples.
• This work presents new possibilities for fabricating advanced solid-state fluorescent sensors.