Interfacing an automatic elemental analyser with an isotope ratio mass spectrometer: The potential for fully automated total nitrogen and nitrogen-15 analysis

An interface between an automatic nitrogen analyser and an isotope mass spectrometer is described. The interface enables total nitrogen analyses and nitrogen isotope ratio measurements to be made semi-automatically, at the rate of 12 h^-1. The precision of the measurements was at the detection limit of the mass spectrometer (0.00026 atom-% ¹⁵N; ±0.7‰). No significant cross-contamination between samples was observed (<0.02% carry over). The potential for full automation and extension of the interface for other stable isotope measurements is discussed.