Ion-Imprinted Chitosan-Based Localized Surface Plasmon Resonance Sensor for Ni²⁺ Detection

Area of Science:

• Environmental Science
• Materials Science
• Analytical Chemistry

Background:

• Heavy metals, such as nickel ions (Ni²⁺), pose significant environmental pollution risks.
• These pollutants can cause diseases in organisms across the food chain, necessitating accurate detection methods.

Purpose of the Study:

• To develop and demonstrate a localized surface plasmon resonance (LSPR) sensor for sensitive and selective detection of Ni²⁺.
• To utilize ion-imprinted chitosan as a recognition element for enhanced sensing performance.

Main Methods:

• Fabrication of an LSPR sensor by coating gold nanoparticles on a multimode fiber.
• Functionalization of the sensor surface with Ni²⁺-imprinted chitosan using dip coating.
• Utilizing ethylene diamine tetra-acetic acid (EDTA) for ion exchange and Ni²⁺ refilling to modulate refractive index and induce wavelength shifts.

Main Results:

• The developed sensor achieved a high sensitivity of 185 pm/μM for Ni²⁺ detection.
• The limit of detection (LOD) for Ni²⁺ was determined to be 0.512 μM.
• Comparative experiments demonstrated superior selectivity of ion-imprinted chitosan over pure chitosan.

Conclusions:

• The proposed LSPR sensor based on ion-imprinted chitosan is effective for Ni²⁺ detection.
• The sensor exhibits excellent sensitivity, a low limit of detection, and enhanced selectivity.
• This technology holds promise for environmental monitoring of heavy metal pollution.