Developing an Automatic Preparation System for Dual Clumped Isotope Measurements in Carbonates

Current challenges in carbonate dual clumped isotope ( Δ 47 – Δ 48 ) analyses include the high cost of commercial systems and the low throughput associated with manual preparation across different laboratories. To address these limitations, we developed a fully automatic preparation system for carbonate samples, coupled to a ThermoFisher Scientific 253 Plus isotope ratio mass spectrometer. The system integrates a programmable logic controller with units for acid digestion, cryogenic purification, and temperature control, enabling continuous operation with minimal supervision. The flexible and low‐cost design achieved through open‐source hardware allows customisation for various research needs and can potentially be adapted for other isotope systems. The system was tested using a series of carbonate reference materials, including in‐house barium carbonates (BSD‐1, BSD‐2), ETH‐1/2/3/4, C1, C2, GU1, and ISTB‐1. The results demonstrate high data repeatability (expressed as 1 standard deviation, 1 s ), with Δ 47 ranging from 0.003‰ to 0.023‰ and Δ 48 from 0.029‰ to 0.078‰. The system's stability was validated over several months, showing no significant drift in normalised values between sessions. We also compared the Δ 47 and Δ 48 values with previously published results, suggesting the potential of carbonate‐based normalisation for achieving consistent Δ 47 – Δ 48 data across different laboratories. Future efforts should include a comprehensive inter‐laboratory comparison using equilibrated gases as primary anchors alongside a wider range of carbonate reference materials to rigorously establish measurement reproducibility across laboratories.