WHAT IT IS
Peripheral devices in isotope ratio mass spectrometry (IRMS) are auxiliary instruments that prepare, convert, or deliver samples to the mass spectrometer. Because the IRMS can only analyze simple gases (such as CO₂, N₂, H₂, SO₂, CO), most solid, liquid, or complex samples must first be transformed. Peripheral units perform this role, extending IRMS applications to environmental, geological, biological, and atmospheric research.
HOW IT WORKS
Peripheral devices function as sample-to-gas converters and transfer systems. They take diverse materials, convert them chemically or physically into analyte gases, purify the gas stream, and regulate timing and flow into the IRMS. Operation is usually automated, with software-controlled valves, autosamplers, and flow regulation to ensure reproducibility and efficient throughput.
TYPES OF PERIPHERAL DEVICES
Elemental Analyzers (EA,TC/EA) – combust or pyrolyze bulk solids and liquids to generate CO₂, N₂, H₂, or SO₂ for isotope ratio analysis of C, N, S, H, and O.
Carbonate and Silicon Devices – specialized reactors for geological materials. Carbonate devices react carbonates with acids to release CO₂ for δ¹³C and δ¹⁸O analysis, while silicon devices use high-temperature conversion of silicates and oxides to CO for δ¹⁸O and δ³⁰Si measurements.
Gas Handling and Preparation Devices – prepare discrete gas samples such as dissolved inorganic carbon or atmospheric gases, purifying and delivering them into the IRMS.
Gas Pre-Concentrators – trap and enrich trace gases (e.g., CO₂, CH₄, N₂O, noble gases) from air, water, or ice cores, then release them as concentrated pulses for sensitive isotopic analysis.
GC-IRMS Interfaces – link gas chromatography with IRMS, enabling compound-specific isotope analysis of volatile and thermally stable compounds.
LC-IRMS Interfaces – couple liquid chromatography to IRMS, designed for polar, non-volatile, and thermally labile compounds such as sugars, amino acids, and nucleotides.
Dual-Inlet Systems – alternate between sample and reference gases, achieving the highest precision in isotope ratio measurements.
CHALLENGES AND LIMITATIONS
Instrumental complexity: each peripheral adds reactors, valves, and columns that require careful setup and maintenance.
Consumables: acids, reagents, oxidation columns, and cryogenic traps must be replaced regularly.
Calibration: each device requires reference materials and dedicated normalization protocols.
Throughput: some peripherals, such as carbonate/silicon devices or pre-concentrators, are slower than continuous-flow elemental analyzers.
Cost and footprint: additional peripherals increase laboratory expenses and space requirements.
See the complete list of devices for IRMS (current & discontinued)