Laser-based analysis of carbon isotope ratios

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Isotope Analysis

Background:

• Isotope ratio mass spectrometry (IRMS) is a standard for precise isotopic analysis.
• Laser resonance spectroscopy offers high specificity but often lacks the sensitivity of IRMS.
• A need exists for techniques combining the strengths of both spectroscopy and mass spectrometry.

Purpose of the Study:

• To develop a novel laser-based technique for analyzing carbon-13:carbon-12 ratios.
• To achieve the specificity of laser spectroscopy with the sensitivity and accuracy of isotope ratio mass spectrometry.
• To provide a highly precise method for isotopic analysis of carbon dioxide.

Main Methods:

• Utilizing laser optogalvanic effect spectroscopy.
• Employing carbon dioxide molecular gas lasers for probing identical transitions.
• Detecting electrical signals in response to optical stimulation of resonance transitions in gas discharge species.

Main Results:

• The technique demonstrates high specificity and sensitivity for isotopic analysis.
• Measurements of carbon dioxide samples yielded carbon-13:carbon-12 ratios with precision better than 10 parts per million.
• A 100-second averaging time was sufficient to achieve this high precision.

Conclusions:

• Laser optogalvanic spectroscopy is a viable and precise method for carbon isotope ratio determination.
• This technique offers a powerful alternative to traditional isotope ratio mass spectrometry.
• The developed method provides accurate and sensitive analysis of carbon-13:carbon-12 ratios in CO2.