Fluorescent Sodium Alginate Hydrogel-Carbon Dots Sensor for Detecting Perfluorooctanoic Acid in Potable Water

Area of Science:

• Environmental Chemistry
• Materials Science
• Analytical Chemistry

Background:

• Per- and polyfluoroalkyl substances (PFASs), particularly perfluorooctanoic acid (PFOA), pose significant environmental and health risks due to their persistence, resistance to degradation, and bioaccumulation.
• Accurate and sensitive detection methods are crucial for monitoring PFAS contamination in water systems.

Purpose of the Study:

• To develop a highly sensitive and selective fluorescence-based sensor for detecting PFOA in natural and engineered water.
• To utilize a composite material of sodium alginate (SA) hydrogel modified with nitrogen and fluorinated carbon dots (N,F-CDs) for enhanced PFOA detection.

Main Methods:

• Fabrication of a sodium alginate hydrogel modified with nitrogen and fluorinated carbon dots (SA hydrogel-N,F-CDs).
• Optimization of fluorescence properties for sensitive detection, with characterization using SEM, FT-IR, PXRD, XPS, and zeta potential spectroscopy.
• Validation of sensor performance through sensitivity, selectivity, and spiked recovery experiments in real water samples.

Main Results:

• The SA hydrogel-N,F-CD composite sensor achieved a low detection limit of 0.001 ppt for PFOA.
• A linear fluorescence response was observed for PFOA concentrations ranging from 1 to 66 ppq.
• The sensor demonstrated high selectivity for PFOA over other perfluorinated compounds and achieved 94%–106.6% recovery rates in tap water samples.

Conclusions:

• The developed SA hydrogel-N,F-CD sensor provides a reliable, efficient, and highly sensitive platform for PFOA detection.
• This sensor shows significant potential for practical, real-world applications in environmental PFAS monitoring.