D4Xgui 1.0.3

Processing app for mass-spectrometric CO₂ clumped isotope (∆₄₇, ∆₄₈, ∆₄₉) data

Welcome to D4Xgui v1.0.3!

D4Xgui is developed to enable easy access to state-of-the-art CO₂ clumped isotope (∆₄₇, ∆₄₈ and ∆₄₉) data processing. A recently developed optimizer algorithm allows pre-processing of mass spectrometric raw intensities utilizing a m/z47.5 half-mass Faraday cup correction to account for the effect of a negative pressure baseline, which is essential for accurate and highest precision clumped isotope analysis of CO₂ (Bernecker et al., 2023). It is backed with the recently published processing tool D47crunch (v.2.4.3) (following the methodology outlined in Daeron, 2021), which allows standardization under consideration of full error propagation and has been used for the InterCarb community effort (Bernasconi et al., 2021). This web-app allows users to discover replicate- or sample-based processing results in interactive spreadsheets and plots.

Example data is accessible from the Data-IO page, or can be downloaded from GitHub. Please check INSTALLATION.md to find help setting up D4Xgui.

In order to process post-background corrected data (Data-IO page, Upload δ⁴⁵-δ⁴⁹ replicates tab), the following columns need to be provided (.xlsx, .csv):

UID	Sample	Session	Timetag	d45	d46	d47	d48	d49

$~$

Baseline correction can be performed using a m/z47.5 half-mass cup. For this purpose either a set of equilibrated gases (via heated-gas-line), or carbonate standards (via target values) is used to determine m/z47, m/z48 and m/z49-specific scaling factors. Please upload a cycle-based spreadsheet (.xlsx, .csv) including the following columns (Data-IO page, Upload m/z44-m/z49 intensities tab):

UID	Sample	Session	Timetag	Replicate

raw_r44	raw_r45	raw_r46	raw_r47	raw_r48	raw_r49	raw_r47.5

raw_s44	raw_s45	raw_s46	raw_s47	raw_s48	raw_s49	raw_s47.5

Please find the code documentation here.