Fluorescence-detected Mid-infrared Photothermal Microscopy

Li, Minghe

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https://hdl.handle.net/2142/116675 Copy

Description

Title

Fluorescence-detected Mid-infrared Photothermal Microscopy

Author(s)

Li, Minghe

Contributor(s)

• Simpson, Garth
• Razumtcev, Aleksandr

Issue Date

2022-06-22

Keyword(s)

Mini-symposium: Benchmarking in Spectroscopy

Abstract

Fluorescence-detected photothermal mid-infrared (F-PTIR) spectroscopy is demonstrated and used to characterize chemical composition within phase-separated domains of pharmaceutical materials. Infrared and Raman spectroscopic imaging are powerful techniques for generating detailed chemical images based on a sample’s spectrum. Previous study on optically detected photothermal infrared (O-PTIR) improved the spatial resolution by probing the temperature-induced refractive index change but are potentially prone to the high background in scattering media. Fluorescence-detected photothermal mid-infrared (F-PTIR) spectroscopy (Fig. 1) is proposed, providing dual-level chemical discrimination based on both fluorescence and infrared absorption. F-PTIR relies on the intrinsic sensitivity of the fluorescence quantum efficiency to temperature. Therefore, fluorescence can serve as a sensitive probe (SNR over 100) for reporting on highly localized and selective infrared absorption. The theoretical spatial resolution of F-PTIR is ultimately limited by fluorescence microscopy and the thermal diffusivity of the sample instead of the infrared wavelength. Following proof-of-concept measurements with model systems of silica gel and polyethylene glycol particles, F-PTIR measurements were used to probe chemical composition within phase-separated domains of ritonavir within copovidone polymer matrices of relevance in the production of pharmaceutical final dosage forms.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Handle URL

https://hdl.handle.net/2142/116675

DOI

https://doi.org/10.15278/isms.2022.WI08

Copyright and License Information

Copyright 2022 held by the authors

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