Succinyl-κ-carrageenan Silver Nanotriangles Composite for Ammonium Localized Surface Plasmon Resonance Sensor

Area of Science:

• Biopolymer Chemistry
• Nanomaterial Science
• Sensor Technology

Background:

• Ammonium (NH4+) detection is crucial for environmental monitoring.
• Existing methods for NH4+ detection have limitations in sensitivity and selectivity.
• Biopolymers offer potential as novel sensing materials due to their unique properties.

Purpose of the Study:

• To synthesize and characterize succinyl-κ-carrageenan as a sensing material.
• To develop a localized surface plasmon resonance (LSPR) sensor using succinyl-κ-carrageenan composited with silver nanoparticles (AgNP) for NH4+ detection.
• To evaluate the sensing performance, including sensitivity, selectivity, and detection limits, of the developed sensor.

Main Methods:

• Succinyl-κ-carrageenan was synthesized by reacting κ-carrageenan with succinic anhydride.
• Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) were used for material characterization.
• The AgNP-Succinyl-κ-carrageenan composite was prepared and tested as an LSPR sensor for NH4+.
• Interaction mechanism studies were conducted using Freundlich and pseudo-second-order kinetic models.

Main Results:

• Succinyl-κ-carrageenan exhibited a smoother topology than pristine κ-carrageenan.
• The AgNP-Succinyl-κ-carrageenan composite showed increased surface roughness and electronegativity compared to the pristine form.
• The AgNP-Succinyl-κ-carrageenan LSPR sensor demonstrated higher sensitivity, selectivity, and a broader detection range for NH4+ compared to AgNP-κ-carrageenan.
• The limit of detection (LOD) and limit of quantification (LOQ) were 0.5964 and 2.7192 ppm, respectively.
• NH4+ adsorption followed a multilayer and chemisorption process.

Conclusions:

• Succinyl-κ-carrageenan is a promising biopolymer for developing high-performance NH4+ LSPR sensors.
• The modified carrageenan enhances the sensitivity and selectivity of AgNP-based LSPR sensors for NH4+ detection.
• The developed sensor offers a viable alternative to conventional NH4+ detection methods with improved performance.