Silver-nanoparticles-loaded chitosan foam as a flexible SERS substrate for active collecting analytes from both solid...

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Surface-enhanced Raman scattering (SERS) offers high sensitivity for chemical detection.
• Developing robust and adaptable SERS substrates is crucial for real-world applications.
• Chitosan is a biocompatible and versatile biopolymer for material fabrication.

Purpose of the Study:

• To create a dual-use SERS substrate for both solid and liquid sample analysis.
• To immobilize silver nanoparticles (Ag NPs) onto a flexible 3D chitosan foam structure.
• To evaluate the substrate's performance in analyte collection, pre-concentration, and detection sensitivity.

Main Methods:

• Fabrication of a 3D chitosan foam scaffold.
• Immobilization of silver nanoparticles (Ag NPs) onto the chitosan foam via amino groups.
• Utilizing the substrate for analyte collection through swabbing (solid) and adsorption (solution).
• Employing gentle pressing for solvent removal and analyte pre-concentration.
• SERS measurements of Raman probes and pesticide samples.

Main Results:

• The developed SERS substrate demonstrated dual-use capability for solid and solution sampling.
• The compressible chitosan foam facilitated rapid analyte pre-concentration.
• Acceptable reproducibility was achieved with a relative standard deviation of 16.4%.
• Detection limits were as low as 5 pg for Nile Blue A (solid) and 10 ppb for Rhodamine 6G (solution).
• Detection of three pesticides (triazophos, methidathion, isocarbophos) at the μg level was successful.

Conclusions:

• The flexible 3D chitosan-based SERS substrate offers a versatile platform for sensitive analyte detection.
• Its adaptable nature and efficient pre-concentration capabilities make it suitable for diverse environmental and chemical sensing applications.
• This SERS substrate shows significant potential for practical, on-site contaminant monitoring.