Amphiphilic Functionalized Acupuncture Needle as SERS Sensor for In Situ Multiphase Detection

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Surface-Enhanced Raman Spectroscopy (SERS) offers unique vibrational fingerprints for molecular detection.
• In situ multiphase detection presents challenges in guiding SERS sensors to target molecules with minimal disturbance.

Purpose of the Study:

• To develop a portable, ultrasensitive, and highly repeatable SERS sensor for in situ multiphase detection.
• To address the challenge of targeting molecules in complex heterogeneous samples.

Main Methods:

• Fabrication of a SERS sensor using a commercial silver acupuncture needle and polyvinylpyrrolidone-coated gold nanoparticles (PVP-Au NPs).
• Utilizing the amphiphilic nature of PVP to promote target molecule adsorption onto the Au-AgN system.
• Direct insertion of the Au-AgN sensor into multiphase systems for in situ laser detection.

Main Results:

• The Au-AgN system exhibits a significant SERS effect due to plasmonic coupling.
• The sensor demonstrated successful in situ detection of target molecules in both oil and water phases.
• Detection at different spots on the sensor provided Raman signals from molecules in distinct phases.

Conclusions:

• The developed Au-AgN sensor is effective for in situ multiphase detection with minimal sampling disturbance.
• The sensor's facile fabrication and amphiphilic functionalization make it a versatile platform for on-site testing.
• This generalized SERS detection platform is suitable for aqueous, organic, and heterogeneous multiphase samples.