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Mid-Infrared Photothermal Spectroscopy for the Detection of Caffeine in Beverages
Giovanna Ricchiuti1, Lisa Riedlsperger1, Alicja Dabrowska1
1Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9/164, 1060 Vienna, Austria.
Sensors (Basel, Switzerland)
|March 28, 2024
Summary
A new laser-based photothermal spectroscopy (PTS) method accurately measures caffeine in beverages. This fast, sensitive, and non-destructive technique offers a promising alternative for food and beverage analysis.
Area of Science:
- Analytical Chemistry
- Spectroscopy
- Biomedical Engineering
Background:
- Caffeine is a widely consumed stimulant with significant health implications.
- Accurate monitoring of caffeine levels in commercial products is crucial for regulatory compliance.
- Existing analytical methods may have limitations in speed, cost, or sample handling.
Purpose of the Study:
- To develop and evaluate a novel caffeine analysis technique using mid-infrared laser-based photothermal spectroscopy (PTS).
- To assess the sensitivity, accuracy, and applicability of PTS for caffeine detection in various beverages.
- To compare the performance of PTS with established methods like gas chromatography (GC) and Fourier-transform infrared (FTIR) spectroscopy.
Main Methods:
- Utilized a tunable quantum cascade laser (QCL) and a Mach-Zehnder interferometer for PTS.
- Developed a custom PTS spectrometer for enhanced mid-infrared measurements.
- Calibrated the instrument using caffeine standards and analyzed samples of coffee, black tea, and energy drinks.
Main Results:
- The PTS method demonstrated high sensitivity and accuracy in quantitative caffeine analysis.
- Results from PTS analysis showed strong agreement with gas chromatography (GC) measurements.
- The achieved limits of detection were comparable to those of a research-grade FTIR spectrometer.
Conclusions:
- Mid-infrared laser-based PTS is a viable and effective alternative for caffeine analysis.
- The developed PTS system offers a fast, sensitive, non-destructive, and consumable-free analytical platform.
- The technology shows high potential for miniaturization, enabling portable caffeine detection solutions.
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