 DESI and DART are considered as pioneer techniques in the field of ambient ionization, since they operate in the open laboratory environment and do not require sample pretreatment.In contrast to the liquid spray used by DESI, the ionizing gas from the DART ion source contains a dry stream containing excited state species.As the gas (M) enters the ion source, an electric potential in the range of +1 to +5 kV is applied to generate a glow discharge.