Real-time isotopic methane detection using mid-infrared spectroscopy.

Area of Science:

• Analytical Chemistry
• Environmental Science
• Spectroscopy

Background:

• Isotopic analysis of methane (CH4) is vital for environmental monitoring and the petroleum industry.
• Accurate and real-time measurement of methane isotopes, specifically ¹²CH₄ and ¹³CH₄, is challenging with existing methods.
• Nondestructive techniques are preferred for in-situ monitoring applications.

Purpose of the Study:

• To develop and demonstrate a real-time, nondestructive mid-infrared (mid-IR) platform for isotopic methane detection.
• To establish a method for identifying the ¹²CH₄/¹³CH₄ isotope ratio using mid-IR spectroscopy.
• To enable in-situ monitoring of methane isotopes for industrial and environmental applications.

Main Methods:

• A measurement system comprising a tunable mid-IR laser, a miniaturized gas chamber, and a mid-IR signal receiver was designed.
• Mid-IR spectra were acquired in the wavelength range of 3.2–3.5 µm to identify the isotope ratio.
• Characteristic mid-IR absorption peaks at 3.328 µm for ¹²CH₄ and 3.340 µm for ¹³CH₄ were utilized for in-situ monitoring.

Main Results:

• The proposed platform enables real-time, nondestructive measurement of the ¹²CH₄/¹³CH₄ isotope ratio.
• The system successfully identified specific mid-IR absorption peaks corresponding to each methane isotope.
• In-situ monitoring of methane isotopes was achieved by tracing these characteristic absorption peaks.

Conclusions:

• The developed mid-IR platform offers a promising solution for real-time, nondestructive isotopic methane analysis.
• This technology has significant potential applications in environmental monitoring, such as tracking greenhouse gas sources.
• The petroleum industry can benefit from this method for exploration, production, and leak detection.