10.1594/PANGAEA.990363Saville, JackJackSaville0000-0003-0492-0720Witwicky, JulienJulienWitwickyGautier, ElsaElsaGautier0000-0003-3053-8349Savarino, JoëlJoëlSavarino0000-0002-6708-9623PANGAEA2026clumped isotopeIce coreisotopemass spectrometrynitrateOrbitrapIce corerDataset10.1021/acs.analchem.6c001833.1 GBytesapplication/zipCreative Commons Attribution 4.0 InternationalThese ESI-Orbitrap MS nitrate isotopologue data quantify d15N-NO3, d18O-NO3, D17O-NO3, D15N18O-NO3 and D18O18O-NO3 in selected samples from the Col du Dome (Mont-Blanc; 45°50'N, 6°51'E, 4236 m a.s.l.) ice core drilled in 2016. This 126 m long core archives ice from approximately the years 1800 - 2016. The nitrate isotopologue data were acquired and processed following the ESI-Orbitrap protocol for natural samples detailed by Saville et al. (in prep), using the Orbitrap Exploris 240 mass spectrometer (Thermo Fisher). The four datasets, obtained in four experiments conducted in 2024-2025 on different batches of ice core samples, were acquired for comparison with traditional IRMS nitrate isotope meausrements previously made on the same samples (Lamothe, 2024), to test the performance of ESI-Orbitrap for NO3 isotopic analysis.File descriptions:
Level 1 data raw files:
Series of .RAW files are high-resolution mass spectra obtained by ESI-Orbitrap during an acquisition sequence, in M0 or no-M0 mode.
Series of .isox files with the same file names as the .RAW files are csv-format tables containing isotopologue data extracted from .RAW files using IsoX software (Version 2022, Thermo Fisher)
Metadata file sequence.csv lists the identity of each .RAW file, in addition to acquisition parameters, in a sequence.

Level 4 treated data files:
results_YYYY-MM-DD.xlsx for each M0 or no-M0 sequence, contains sheets tabulating injection average isotopologue ratios and metadata, bracketed isotopologue delta values for each sample injection and a summary of bracketed internal delta values where replicate analyses are averaged
CdD16-xxxx-NO3_calibrated_M0+noM0_YYYY-MM-DD.xlsx, for each combination of M0 and noM0 results on the same sample batch, contains sheets tabulating uncalibrated delta values, calibrated delta values, and derived capital Delta values, as well as calibration metadata
CdD16-xxxx-NO3_calibrated_M0-only_YYYY-MM-DD.xlsx, as above but for cases where only M0 data was available6.8545.8333Mont Blanc massifEuropean Research Councilhttps://doi.org/10.13039/501100000781101054558Deciphering the Oxidizing Capacity of the PAST atmosphere