A molecularly imprinted fluorescence nanosensor based on upconversion metal-organic frameworks for alpha-cypermethrin...

Area of Science:

• * Analytical Chemistry
• * Materials Science
• * Nanotechnology

Background:

• * Alpha-cypermethrin (α-CPM) is a widely used insecticide with potential environmental and health concerns.
• * Sensitive and selective detection methods are crucial for monitoring α-CPM residues.
• * Existing detection methods may lack sensitivity or require complex sample preparation.

Purpose of the Study:

• * To develop a novel, highly sensitive fluorescent nanosensor for the determination of trace α-CPM.
• * To utilize zeolitic imidazolate frameworks-8 (ZIF-8) and upconversion nanoparticles (UCNPs) for enhanced sensing performance.
• * To validate the sensor's efficacy in real sample analysis.

Main Methods:

• * Synthesis of UCNPs as the luminescent core.
• * Layer-by-layer self-assembly of UCNPs with ZIF-8 to form a protective and enhancing layer.
• * Fabrication of molecularly imprinted polymers (MIPs) on the UCNPs@ZIF-8 support using α-CPM as the template.
• * Fluorescence quenching assay for α-CPM detection.

Main Results:

• * The UCNPs@ZIF-8@MIP nanosensor exhibited sensitive fluorescence quenching in response to α-CPM.
• * A linear relationship was observed between fluorescence intensity and α-CPM concentration in the range of 0.10-12 mg L⁻¹.
• * A low detection limit of 0.03 mg L⁻¹ (S/N=3) was achieved.
• * The nanosensor demonstrated satisfactory performance in detecting α-CPM in real samples, with results consistent with GC-MS analysis.

Conclusions:

• * The developed UCNPs@ZIF-8@MIP nanosensor is a promising tool for sensitive and selective detection of trace α-CPM.
• * The combination of UCNPs and ZIF-8 enhances sensor performance through improved mass transfer and fluorescence.
• * This approach offers a viable alternative for α-CPM residue analysis in environmental and food safety applications.