Diffuse reflection mid-infrared spectroscopy of neat powders by using a wire mesh "Button" sample holder

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Materials Science

Background:

• Traditional mid-infrared spectroscopy often requires diluting neat powders in a non-absorbing matrix.
• Sample preparation can be time-consuming and may introduce artifacts.
• Developing methods for direct analysis of solid samples is crucial for efficiency.

Purpose of the Study:

• To present a new approach for direct mid-infrared spectroscopy of neat powder samples.
• To demonstrate the effectiveness of stainless steel buttons with wire meshes for sample support.
• To achieve high sensitivity and artifact-free spectra without sample dilution.

Main Methods:

• Neat powder samples were prepared as thin layers supported by wire meshes on stainless steel buttons.
• Samples were analyzed using a praying mantis diffuse reflection optical system.
• Spectra were obtained by placing the sample-loaded buttons at the infrared beam focus.

Main Results:

• Artifact-free mid-infrared spectra were acquired for powder layers several microns thick.
• The method demonstrated nanogram detection limits for a benzoic acid coating.
• Stainless steel buttons proved durable, reusable, and easy to clean.

Conclusions:

• This method offers a robust and sensitive approach for direct mid-infrared spectroscopy of neat powders.
• The use of stainless steel buttons and wire meshes simplifies sample handling and preparation.
• The technique is suitable for a wide range of powder samples, enabling efficient analysis.