Quantification of trace chemicals in unknown complex systems by SERS.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Trace chemical analysis demands sensitive, rapid, and cost-effective methods.
• Existing techniques often struggle to meet all these requirements simultaneously.
• Surface-enhanced Raman scattering (SERS) offers potential for high sensitivity.

Purpose of the Study:

• To investigate the use of a portable Raman system with SERS for facile and accurate quantitative analysis of chemicals in unknown samples.
• To develop a method for determining initial concentrations of target analytes without prior knowledge of the sample composition.
• To demonstrate the versatility of the SERS approach across different chemical analytes and matrices.

Main Methods:

• A three-step SERS-based quantitative analysis protocol was developed.
• Involves controlled addition of target chemicals to unknown solutions to generate calibration curves based on SERS peak intensity.
• Utilized a portable Raman system for spectral acquisition and analysis.

Main Results:

• The method accurately predicted concentrations of 2-Naphthalenethiol (2-NaT) and 4-Mercaptopyridine (4-MPY) in single and binary solutions.
• Successfully quantified malachite green (MG) in fish water and benzidine in groundwater samples.
• Demonstrated a strong correlation between SERS peak intensity increment and analyte concentration.

Conclusions:

• The developed SERS approach provides an accurate, facile, and rapid method for quantitative chemical analysis in complex, unknown systems.
• This technique effectively leverages the sensitivity of SERS for practical field applications.
• The portable system enhances the accessibility and applicability of SERS for on-site chemical detection.