Layer-by-layer self-assembly xylenol orange functionalized CdSe/CdS quantum dots as a turn-on fluorescence lead ion...

Area of Science:

• Nanomaterials Science
• Analytical Chemistry
• Environmental Science

Background:

• Quantum dots (QDs) offer unique optical properties for sensing applications.
• Lead (Pb2+) is a toxic heavy metal requiring sensitive detection methods.
• Developing selective and sensitive turn-on fluorescence sensors is crucial for environmental monitoring.

Purpose of the Study:

• To develop a turn-on fluorescence sensor for sensitive lead ion (Pb2+) determination.
• To utilize xylenol orange (XO) functionalized cadmium selenide/cadmium sulfide (CdSe/CdS) quantum dots (QDs).
• To investigate the sensing mechanism based on fluorescence recovery.

Main Methods:

• Layer-by-layer self-assembly of mercaptoacetic acid (MAA)-modified CdSe/CdS QDs with chitosan and XO.
• Fluorescence quenching of QDs by XO via electron transfer.
• Fluorescence recovery upon Pb2+ addition due to coordination with XO and disruption of electron transfer.
• Linear regression analysis to correlate fluorescence intensity with Pb2+ concentration.

Main Results:

• A turn-on fluorescence response was observed for Pb2+ detection.
• The fluorescence recovery showed a linear relationship with Pb2+ concentration in the range of 0.05–6 μmol L(-1).
• A low detection limit of 0.02 μmol L(-1) was achieved.
• The sensor demonstrated successful application in real sample analysis.

Conclusions:

• The developed XO-functionalized QD sensor provides a sensitive and selective method for Pb2+ determination.
• The turn-on fluorescence mechanism is effective for detecting lead ions.
• This sensor shows potential for environmental monitoring and analysis of lead in real samples.