A line-scan hyperspectral system for high-throughput Raman chemical imaging

Area of Science:

• Spectroscopy
• Chemical Imaging
• Analytical Chemistry

Background:

• Raman spectroscopy is a powerful technique for chemical analysis.
• Traditional Raman imaging can be time-consuming for large sample areas.

Purpose of the Study:

• To develop a line-scan hyperspectral system for efficient Raman chemical imaging of large samples.
• To demonstrate the system's capability in authenticating food products.

Main Methods:

• Utilized a custom 785 nm line laser and scanning mirror for excitation.
• Employed a dispersive imaging spectrograph and CCD camera for signal detection.
• Accumulated data line-by-line using a motorized stage for transverse sample movement.

Main Results:

• The system achieved a 23 cm wide imaging area with a Raman shift range of -648.7 to 2889.0 cm⁻¹.
• Acquired a 512 × 110 × 1024 hypercube (56,320 spectra) in 4 minutes from multiple powder samples.
• Successfully generated chemical images to detect melamine and dicyandiamide adulterants in milk powder.

Conclusions:

• The developed line-scan hyperspectral system significantly enhances the speed and area coverage for Raman chemical imaging.
• This system offers a robust solution for rapid authentication and quality control of powdered food products.