GasBench II, which is universal on-line gas preparation and introduction system. The combination of GasBench interface and Isotope Ratio Mass Spectrometry is a promising method for the δ15N analysis of samples containing trace amounts of nitrogen. Some time ago we solved problem with high background of nitrogen in the atmosphere and RSD of obtained analysis! Tests were prepared in a special glovebox designed by Dr Marta Borecka and made by Mr. Zbigniew Ciećwierz. Now we will try to figure out troubles with background of mass 30N2. Establishment of the methodology on GasBench/isotope ratio mass spectrometry (GasBench/IRMS) system will allow us to determine anammox and denitrification processes occurring in the marine environment. Fot. Magdalena Diak