D4Xgui: A tool for baseline correction and standardization of carbonate clumped isotope raw data

Accurate and precise mass spectrometric determination of ppm-ppb quantities of mass 47–49 clumped isotopologues of carbonate-derived CO 2 , expressed as Δ 47 – Δ 49 values, requires advanced processing schemes. Here, we introduce D4Xgui, a user-friendly processing tool that allows correction of mass-spectrometric raw intensities for a pressure baseline artifact, before standardization is carried out using D47crunch. D4Xgui enables rapid processing of multi-session data under consideration of full error-propagation, interactive visualization of results including tools for data quality assurance, calculation of carbonate crystallization temperature from finally processed data, and rapid re-evaluation of datasets with revised processing parameters. Though the primary focus of D4Xgui is on carbonates it can also be applied to the correction of mass spectrometric raw data obtained on CO 2 from other sources.