The Pfeiffer Omnistar GSD 320 mass spectrometer (MS) is a bench-top instrument for detecting atomic mass units (amu) between 1 and 200. It uses a W filament, a QMA 200 quadrupole mass analyzer and a QMG 220 continuous secondary electron multiplier(C-SEM) detector, or alternatively a Faraday cup. It is attachable to our TA Instruments Discovery TG via a capillary and heated adapter. The gas inlet capillary can be heated up to 200 °C.