A glow discharge mass spectrometry device and method, the device including a glow discharge lamp (1), gas flow-injection elements, the glow discharge lamp being suitable for forming an ablation plasma in the presence of a plasma gas, and a mass spectrometer. The device further includes heating elements (30, 31) suitable for heating a gas flow (38) upstream of a cell (2), the gas flow-injection elements being suitable for injecting into the glow discharge cell a gas flow (38) heated to a temperature T for a duration D, and pumping elements (7, 27) being designed to pump a flow of gaseous species (17, 37) out of the cell for the duration D, so as to decontaminate the surface of the sample (4) and/or the inner walls of the glow discharge cell (2) before an ablation plasma (5) is ignited.