WHAT IT IS
Gas handling and preparation devices are peripheral units connected to isotope ratio mass spectrometers (IRMS) that prepare gaseous samples for isotopic analysis. They are designed to handle pure gases or convert specific compounds into simple molecules such as CO₂, N₂, or H₂, which can then be introduced into the IRMS. These devices are often used for carbonates, dissolved inorganic carbon, atmospheric gases, or headspace analyses. They serve as an interface between diverse sample types and the continuous-flow IRMS system.
HOW IT WORKS
Samples are introduced into the device either manually (via sealed vials or flasks) or automatically (via autosampler systems). Inside the unit, chemical or physical processes release or purify the target gases:
Carbonates are reacted with acids to produce CO₂ for δ¹³C and δ¹⁸O analysis.
Dissolved inorganic carbon can be liberated from water samples in sealed vials.
Air or gas mixtures are purified, removing contaminants such as water vapor or unwanted gases.
The prepared gases are carried by a continuous helium stream through chromatographic or flow control systems that separate the analytes in time. Well-defined gas pulses are then directed into the IRMS ion source. Software-controlled valves and flow regulators ensure accurate sample delivery and reproducibility.
ADVANTAGES
Flexible sample preparation – accommodates diverse sample types, including carbonates, gases, and dissolved inorganic carbon.
Automated workflows – when paired with autosamplers, dozens of samples can be processed in sequence with minimal manual input.
Accurate gas purification – removal of contaminants improves precision and reduces background interference.
Direct IRMS interface – optimized for stable, reproducible introduction of small gas volumes.
Expanded application range – extends IRMS use beyond solid or bulk analyzers to environmental, geological, and atmospheric studies.
CHALLENGES AND LIMITATIONS
Instrument complexity – precise valve systems, flow controls, and reactors require regular calibration and maintenance.
Consumable needs – acids, reagents, and drying agents must be replenished frequently.
Sample constraints – best suited for small, defined gas volumes; not applicable to bulk elemental analyses.
Risk of contamination – improper sealing or handling may introduce atmospheric gases, affecting isotopic results.
Higher costs – peripheral units add to the overall expense of IRMS setups and increase laboratory footprint.