An Advanced Hand-Held Microfiber-Based Sensor for Ultrasensitive Lead Ion Detection.

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Heavy metal ion contamination, particularly lead (Pb²⁺), poses significant risks to public health and ecosystems.
• Accurate and sensitive detection methods are essential for monitoring water quality and enforcing safety standards.
• Existing methods for heavy metal detection can be costly, time-consuming, and require laboratory settings.

Purpose of the Study:

• To develop a highly selective and sensitive sensor for detecting trace levels of heavy metal ions in aqueous solutions.
• To demonstrate the efficacy of a l-glutathione-modified nonadiabatic microfiber sensor for lead ion detection.
• To propose a compact, all-fiber-based interrogation scheme for portable, on-site heavy metal analysis.

Main Methods:

• Fabrication of a nonadiabatic microfiber sensor modified with l-glutathione.
• Testing the sensor's response to various heavy metal ions, focusing on selectivity towards Pb²⁺.
• Development and validation of a novel, compact all-fiber interrogation scheme using fiber Bragg gratings (FBGs) and photodetectors.

Main Results:

• The l-glutathione-modified microfiber sensor exhibited exclusive selectivity for Pb²⁺ ions over other tested metal ions.
• A low detection limit of 5 μg/L for Pb²⁺ was achieved, which is below the World Health Organization's maximum allowable limit for drinking water.
• The proposed interrogation scheme successfully operated using reflected optical power, eliminating the need for bulky laboratory equipment.

Conclusions:

• The developed sensor offers a promising solution for sensitive and selective detection of lead in water.
• The compact, all-fiber interrogation system paves the way for portable, hand-held devices for real-time, on-site water quality monitoring.
• This technology can contribute to improved public health by facilitating accessible and reliable heavy metal testing in drinking water.