Chemical sensing by differential thermal analysis with a digitally controlled fiber optic interferometer

Area of Science:

• Analytical Chemistry
• Optical Physics
• Instrumentation Engineering

Background:

• Differential Thermal Analysis (DTA) is crucial for identifying chemical species based on thermal properties.
• Optical fiber interferometry offers high sensitivity for precise measurements.
• Integrating these technologies can lead to novel analytical instrumentation.

Purpose of the Study:

• To implement and evaluate an optical fiber interferometric system for DTA.
• To compare the performance of standard hardware versus low-cost virtual instrumentation for DTA.
• To demonstrate the system's capability in identifying chemical species.

Main Methods:

• A white light Mach-Zehnder interferometer was configured.
• Two identical fiber Bragg gratings (FBGs) were interrogated in a differential scheme.
• Pseudo-heterodyne demodulation was employed for signal processing.
• System performance was assessed using both standard and virtual instrumentation.

Main Results:

• The virtual instrumentation system achieved a temperature resolution of ±0.023 °C.
• This resolution closely matched the performance of standard hardware.
• The system successfully discriminated between chemical species, identifying mixed samples of acetone and methanol.

Conclusions:

• The developed optical fiber interferometric system is suitable for high-precision DTA.
• Low-cost virtual instrumentation provides comparable performance to standard hardware.
• The system demonstrates potential for accurate chemical species identification in various applications.