Abstract The global helium shortage is a very serious issue that is affecting a variety of scientific research organizations that utilize this gas for their work. In particular, gas chromatography-mass spectrometry (GC-MS) is a widely used analytical technique that traditionally uses helium as the GC carrier gas. Consequently, it has become critical to identify other carrier gases for GC-MS in order to minimize the effects of the helium shortage. Previously, we changed the GC-MS carrier gas from helium (He) to nitrogen (N2) to determine how this affects sensitivity when using the dedicated EI ion source. The results showed that the detection sensitivity for N2 as the GC carrier gas was 1/18 of the level when compared to He. In this work, we compare sensitivity levels when using the combination EI/FI and EI/PI ion sources when He and N2 are used as the GC carrier gas. Please click below to read more.