Tapered Mach-Zehnder interferometer based on PbS quantum dots modified by polymers for copper ion sensing

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Accurate detection of copper ions (Cu2+) is crucial for environmental monitoring and biological studies.
• Existing methods for Cu2+ detection often face challenges with selectivity, sensitivity, or applicability in complex matrices.
• Optical fiber sensors offer advantages like remote sensing, immunity to electromagnetic interference, and miniaturization.

Purpose of the Study:

• To develop and characterize a novel optical fiber interferometer sensor for the detection of copper ions (Cu2+).
• To investigate the role of lead sulfide quantum dots (PbS QDs) and a multifunctional copolymer in enhancing sensor performance.
• To evaluate the sensor's selectivity, detection range, and limit of detection in aqueous and biological samples.

Main Methods:

• Fabrication of an optical fiber interferometer coated with PbS quantum dots (QDs).
• Modification of QDs with a multifunctional copolymer for improved surface ligation, dispersion, and Cu2+ coordination.
• Utilizing changes in the refractive index of the interferometer due to Cu2+ coordination for signal transduction.
• Testing sensor performance in terms of selectivity, linearity, and limit of detection.

Main Results:

• The developed sensor demonstrated high selectivity for copper ions (Cu2+).
• A linear detection range from 0 to 1000 µM was achieved for Cu2+.
• The sensor exhibited a low limit of detection of 2.20 µM.
• The sensor performed effectively in both aqueous and biological solutions.

Conclusions:

• The PbS QD-coated optical fiber interferometer is a promising platform for sensitive and selective Cu2+ detection.
• The multifunctional copolymer plays a key role in the sensor's functionality and performance.
• This sensor technology has potential applications in environmental and biomedical fields requiring Cu2+ monitoring.