The process of removing dissolved gas from the mobile phase before or during use. Dissolved gas may come out of solution in the detector cell and cause baseline spikes and noise. Dissolved air can affect electrochemical detectors (by reaction) or fluorescence detectors (by quenching). Degassing is carried out by heating the solvent or by vacuum (in a vacuum flask), or on-line using evacuation of a tube made from a gas-permeable substance such as PTFE, or by helium sparging.