Simple software solution for N₂ diversion when measuring δ¹⁸O values of nitrogen-rich samples materials using a...

This method is a simple, cost-free, and reliable approach for the removal of N₂ interference on a CO analyte when analysing nitrogen-rich (>0.5% w/w) samples by Elemental Analysis Isotope Ratio Mass Spectrometry. Specifically, the isobaric interference on m/z 30 is eliminated using only the open split of the Thermo Scientific ConFlo IV Universal Interface Device, improving the analytical workflow when using a static temperature Gas Chromatography (GC) column. It simplifies the N₂ diversion methods described in recent decades. When applied, the method described here:•Provides sufficient baseline resolution between the N₂ and CO analytes, to permit quantitative N₂ diversion, using an extended length packed GC column;•Quantitatively eliminates all N₂ analyte from the analytical gas stream ensuring that no N₂ enters the ion source and therefore no isobaric interference is produced on m/z 30 ion trace of the CO analyte;•Allows reproducible measurement of δ¹⁸O values from nitrogen-rich sample materials without a N₂ isobaric interference, where the CO analyte is measured on the analytical baseline that it was produced on in the reactor (i.e., no addition make-up helium or new baseline of pure helium for the CO analyte).