High-Resolution Mass Spectrometry for Nitrate Aerosol Isotopologue Quantification: Method Development, Calibration, and Application to Atmospheric Samples
Abstract
Variations in the stable isotope ratios of nitrate (NO 3 – ) provide powerful constraints on atmospheric oxidation chemistry and source apportionment; however, traditional isotope ratio mass spectrometry (IRMS) methods require large sample sizes (≥50 nmol) and specialized setups and cannot access multiply substituted (“clumped”) isotopologues. We present a new high-resolution electrospray ionization Orbitrap mass spectrometry (ESI-Orbitrap) approach for direct quantification of NO 3 – isotopologues paired with an optimized preparation workflow to minimize matrix- and concentration-dependent biases. Accurate isotopic measurement was highly sensitive to sample concentration and coextracted solutes, with deviations up to 3–5‰ in δ 18 O and δ 17 O for unpurified or dilute (
Fields of Study & Subjects
Atmospheric chemistry and aerosols
Groundwater and Isotope Geochemistry
Atmospheric Ozone and Climate
Publication details
- Journal / source
- Analytical Chemistry
- Publisher
- American Chemical Society (ACS)
- Volume
- 98
- Issue
- 2
- Pages
- 1699–1709
- Publication date
- 8 January 2026
- Language
- EN