Attenuated total internal reflection infrared microspectroscopic imaging using a large-radius germanium internal...

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Fourier transform infrared (FT-IR) microspectroscopic imaging techniques and instruments have advanced rapidly.
• Attenuated total internal reflectance (ATR) FT-IR microspectroscopy offers reduced sample preparation and simplified analysis for difficult samples.

Purpose of the Study:

• To investigate the expansion of the field of view in ATR-FT-IR microspectroscopic imaging.
• To evaluate the impact of a larger internal reflection element on imaging parameters and performance.
• To demonstrate the applicability of the enhanced technique in pharmaceutical analysis.

Main Methods:

• Utilized a larger internal reflection element (12.5 mm radius) to increase the field of view in ATR-FT-IR microspectroscopic imaging.
• Evaluated parameters such as penetration depth, active area, magnification, and spatial resolution.
• Applied the technique to analyze polydimethylsiloxane foam, latent fingerprints, and a model inorganic mixture.

Main Results:

• The field of view was increased by 70x, from 300 x 300 microm to 2500 x 2500 microm.
• Analyzed changes in penetration depth, active area, magnification, and spatial resolution across the expanded imaging area.
• Successfully demonstrated the technique's utility for FT-IR imaging of various samples, including pharmaceutical applications.

Conclusions:

• Expanding the field of view in ATR-FT-IR microspectroscopic imaging enhances its analytical capabilities.
• The method is effective for analyzing diverse samples and shows promise for pharmaceutical applications.
• Considerations such as large file sizes need to be managed for practical implementation.